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SUMMARY: The R-spondin protein family is a group of proteins that enhance Wnt/b-catenin signaling and have pleiotropic functions in stem cell growth and development. In the literature reviews, there is no histomorphological study showing the localization and distribution of R-spondins in different hypothalamic nuclei. For this reason, the purpose of this study was to determine the localization, distribution characteristics, and densities in the hypothalamic nuclei of neurons expressing Rspo1 and Rspo3 proteins. The free-floating brain sections of the male rats who were not exposed to any treatment were stained with the indirect immunoperoxidase method using the relevant antibodies. As a result of the immunohistochemical studies, it was determined that neurons expressing the Rspo1 protein were found in large numbers in the supraoptic nucleus (SON), the suprachiasmatic nucleus (SCh), anterior paraventricular nucleus, periventricular hypothalamic nucleus (PeV), anterior hypothalamic area, magnocellular preoptic nucleus (MCPO) and the lateral hypothalamic area (LH) from the hypothalamic nuclei, while they were localized in fewer numbers in the arcuate nucleus (ARC). Rspo3 protein expression was found in neurons localized in the hypothalamic nuclei SON, paraventricular nucleus (PVN), PeV, ARC, ventromedial nucleus (VMH), LH, anterior parvicellular nucleus, and zona inserta (ZI). In addition, neurons synthesizing both peptides were found in the cortex and hippocampus regions (H). Rspo1 and 3 proteins are expressed in hypothalamic energy homeostatic areas, thus these proteins may be involved in the regulation of food intake.

La familia de proteínas R-espondina es un grupo de proteínas que mejoran la señalización de Wnt/b-catenina y tienen funciones pleiotrópicas en el crecimiento y desarrollo de las células madre. En las revisiones de la literatura no existen estudios histomorfológicos que muestren la localización y distribución de las R-espondinas en diferentes núcleos hipotalámicos. Por esta razón, el propósito de este estudio fue determinar la localización, características de distribución y densidades en los núcleos hipotalámicos de neuronas que expresan las proteínas Rspo1 y Rspo3. Secciones de cerebro flotantes de ratas macho que no fueron expuestas a ningún tratamiento se tiñeron con el método de inmunoperoxidasa indirecta utilizando los anticuerpos pertinentes. Como resultado de los estudios inmunohistoquímicos, se determinó que las neuronas que expresan la proteína Rspo1 se encontraron en gran número en el núcleo supraóptico (SON), el núcleo supraquiasmático (SCh), el núcleo paraventricular anterior, el núcleo hipotalámico periventricular (PeV), el núcleo hipotalámico anterior área, núcleo preóptico magnocelular (MCPO) y el área hipotalámica lateral (LH) de los núcleos hipotalámicos, mientras que se localizaron en menor número en el núcleo arqueado (ARC). La expresión de la proteína Rspo3 se encontró en neuronas localizadas en los núcleos hipotalámicos SON, núcleo paraventricular (PVN), PeV, ARC, núcleo ventromedial (VMH), LH, núcleo parvicelular anterior y zona inserta (ZI). Además, se encontraron neuronas que sintetizan ambos péptidos en las regiones de la corteza y el hipocampo (H). Las proteínas Rspo1 y 3 se expresan en áreas homeostáticas de energía hipotalámicas, por lo que estas proteínas pueden estar involucradas en la regulación de la ingesta de alimentos.

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Osteoporosis is a metabolic condition distinguished by the degradation of bone microstructure and mechanical characteristics. Traditional Chinese medicine (TCM) has been employed in China for the treatment of various illnesses. Naringin, an ingredient found in Drynariae TCM, is known to have a significant impact on bone metabolism. For this research, we studied the precise potential effect of Drynaria Naringin on protecting against bone loss caused by stress deficiency. In this study, a tail-suspension (TS) test was performed to establish a mouse model with hind leg bone loss. Some mice received subcutaneous injections of Drynaria Naringin for 30 d. Trabecular bone microarchitecture was evaluated using micro-computed tomography analysis and bone histological analysis. Bone formation and resorption markers were quantified in blood samples from mice or in the supernatant of MC3T3-E1 cells by ELISA analysis, Western blotting, and PCR. Immunofluorescence was utilized to visualize the location of ß-catenin. Additionally, siRNA was employed to knockdown-specific genes in the cells. Our findings highlight the efficacy of Drynaria Naringin in protecting against the deterioration of bone loss and promoting bone formation and Rspo1 expression in a mouse model following the TS test. Specifically, in vitro experiments also indicated that Drynaria Naringin may promote osteogenesis through the Wnt/ß-catenin signalling pathway. Moreover, our results suggest that Drynaria Naringin upregulates the expression of Rspo1/Lgr4, leading to the promotion of osteogenesis via the Wnt/ß-catenin signalling pathway. Therefore, Drynaria Naringin holds potential as a therapeutic medication for osteoporosis. Drynaria Naringin alleviates bone loss deterioration caused by mechanical stress deficiency through the Rspo1/Lgr4-mediated Wnt/ß-catenin signalling pathway.

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Alveolar macrophages (AMs) are self-maintained immune cells that play vital roles in lung homeostasis and immunity. Although reporter mice and culture systems have been established for studying macrophages, an accurate and specific reporter line for alveolar macrophage study is still not available. Here we reported a novel Rspo1-tdTomato gene reporter mouse line that could specifically label mouse AMs in a cell-intrinsic manner. Using this reporter system, we visualized the dynamics of alveolar macrophages intravitally under steady state and characterized the alveolar macrophage differentiation under in vitro condition. By performing ATAC-seq, we found that insertion of the tdTomato cassette in the Rspo1 locus increased the accessibility of a PPARE motif within the Rspo1 locus and revealed a potential regulation by key transcription factor PPAR-γ for alveolar macrophage differentiation in vitro and in vivo. Consistently, perturbation of PPAR-γ by its agonist rosiglitazone or inhibitor GW9662 resulted in corresponding alteration of tdTomato expression in alveolar macrophages together with the transcription of PPAR-γ downstream target genes. Furthermore, global transcriptomic analyses of AMs from the wild type mice and the Rspo1-tdTomato mice showed comparable gene expression profiles, especially those AM-specific genes, confirming that the insertion of the tdTomato cassette in the Rspo1 locus does not impact the cell identity and biological function of AMs under normal condition. Taken together, our study provides an alternative tool for in vivo and in vitro labeling of alveolar macrophages with high specificity which could also be utilized as an indicator of PPAR-γ activity for future development of PPAR-γ specific targeting drugs.

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BACKGROUND: The pathogenesis of Legg-Calve-Perthes disease (LCPD), a juvenile form of avascular necrosis of the femoral head (ANFH), is not fully understood. OBJECTIVES: The purpose of this work was to study the regulatory effect of R-spondin 1 (Rspo1) on osteoblastic apoptosis and evaluate the pre-clinical efficacy of recombinant human protein Rspo1 (rhRspo1) in treatment of LCPD. MATERIAL AND METHODS: This is an experimental study. In vivo rabbit ANFH model was established. Human osteoblast cell line hFOB1.19 (hFOB) was used to overexpress and silence Rspo1 in vitro. Additionally, hFOB cells were induced with glucocorticoid (GC) and methylprednisolone (MP), and treated with rhRspo1. The expressions of Rspo1, ß-catenin, Dkk-1, Bcl-2, and caspase-3, and the apoptosis rate of hFOB cells were examined. RESULTS: The expressions of Rspo1 and ß-catenin were lower in ANFH rabbits. The expression of Rspo1 was decreased in GC-induced hFOB cells. Compared to the control group, after 1 µM MP induction for 72 h, the expressions of ß-catenin and Bcl-2 were higher, while Dkk-1, caspase-3 and cleaved caspase-3 expressions were lower in Rspo1 overexpression and rhRspo1-treated groups. The apoptosis rate of GC-induced hFOB cells was decreased in Rspo1 overexpression and rhRspo1-treated groups compared to the control group. CONCLUSIONS: R-spondin 1 inhibited GC-induced osteoblast apoptosis via Wnt/ß-catenin pathway, which might be associated with the development of ANFH. Moreover, rhRspo1 had a potential pre-clinical therapeutic effect on LCPD.

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R-spondin 1 (RSPO1) is a ligand for the intestinal stem cell (ISC) marker Lgr5 in the crypt, which functions to amplify canonical Wnt signaling to stimulate the division of ISCs. Despite the crucial role of recombinant human RSPO1 (rhRSPO1) in homeostasis and regeneration, little is known about RSPO1 among different species. Here, we cloned the porcine RSPO1 (pRSPO1) gene and obtained rpRSPO1 protein through the expression system of the recombinant Escherichia coli Rosetta (DE3) chemical competent cells. Using the in vitro IPEC-J2 model that combines cell proliferation evaluation approaches, we identified the rpRSPO1 activity in stimulating jejunal epithelial cells. And upon deoxynivalenol challenge in mice, we found that rpRSPO1 ameliorated their growth retardation and jejunal epithelial integrity. Importantly, the ISCs in the jejunum had greater proliferation and differentiation potential that was accompanied by Wnt/ß-catenin pathway activation after rpRSPO1 modulation. Subsequently, the jejunal organoids expanded from these ISCs ex vivo presented robust growth advantages. And the rpRSPO1 was able to guide Wnt/ß-catenin activity to increase ISC activity. Our work systematically demonstrates that rpRSPO1 facilitates ISC expansion by potentiating Wnt/ß-catenin signaling during homeostasis and responding to deoxynivalenol perturbations.

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OBJECTIVE: Hair loss and greying affect men and women of all ages, often causing psychosocial difficulties. Dickkopf-1 (DKK1), a major hair loss factor secreted from dermal papilla (DP) cells in response to the secretion of dihydrotestosterone (DHT), has been reported to induce and accelerate androgenetic alopecia (AGA). In addition, DKK1 acts as a potent suppressor of melanogenesis and is closely related to hair colour. R-spondin 1 (RSPO1) is a secretory agonist of Wnt signalling known to antagonize the effects of DKK1, including DKK1-mediated hair follicle suppression. In this study, we investigated the effect of watercress extract (WCE) on the secretion of RSPO1 and DKK1 from DP cells as well as its anti-hair loss effect in human hair follicles and patients. METHODS: The in vitro secretion of RSPO1 and DKK1 was measured by ELISA. Human hair follicles were collected from the scalp of a female donor and used for ex vivo organ culture to investigate the effects of WCE on human hair loss. Finally, a 6-month human clinical trial was conducted to examine the effect of WCE-containing lotion on hair growth in a male panel. RESULTS: WCE significantly upregulated RSPO1 secretion and suppressed DKK1 secretion in a dose-dependent manner, even in the presence of DHT. WCE-treated hair follicles elongated 1.6-fold compared with the control, and the level of RSPO1 production in DP as well as RSPO1 bound to the outer root sheath (ORS) increased. In the clinical trial, the hair lotion containing 2% WCE increased hair thickness and density to improve against hair loss symptoms. CONCLUSION: WCE exhibited a strong anti-androgenic effect through its ability to suppress DKK1 secretion and antagonize DKK1 via RSPO1. These findings highlighted the potential use of WCE for the treatment of hair loss.

OBJECTIF: La perte de cheveux et le grisonnement touchent des hommes et des femmes de tous âges, ce qui entraîne souvent des difficultés psychosociales. Selon des rapports, Dickkopf-1 (DKK1), un facteur de perte de cheveux majeur sécrété par les cellules de la papille dermique (PD) en réponse à la sécrétion de dihydrotestostérone (DHT), induit et accélère l'alopécie androgénétique (AAG). En outre, DKK1 agit comme un puissant suppresseur de la mélanogenèse et est étroitement lié à la couleur des cheveux. La protéine R-spondin 1 (RSPO1) est un agoniste sécrétoire de la voie de signalisation Wnt connue pour antagoniser les effets de DKK1, notamment la suppression des follicules pileux médiée par DKK1. Dans cette étude, nous avons étudié l'effet de l'extrait de cresson sur la sécrétion de RSPO1 et de DKK1 à partir des cellules de la PD, ainsi que son effet anti-perte de cheveux sur les follicules pileux humains et chez les patients. MÉTHODES: La sécrétion in vitro de RSPO1 et de DKK1 a été mesurée à l'aide de la méthode ELISA. Des follicules pileux humains ont été prélevés sur le cuir chevelu d'une femme et utilisés pour une culture d'organes ex vivo afin d'étudier les effets de l'extrait de cresson sur la perte de cheveux humains. Enfin, un essai clinique de 6 mois chez l'être humain a été mené pour examiner l'effet d'une lotion contenant de l'extrait de cresson sur la croissance des cheveux au sein d'un panel d'hommes. RÉSULTATS: L'extrait de cresson a significativement régulé à la hausse la sécrétion de RSPO1 et a supprimé la sécrétion de DKK1 de manière dose-dépendante, même en présence de DHT. Les follicules pileux traités avec de l'extrait de cresson ont été multipliés par 1,6 par rapport au groupe témoin, et le niveau de production de RSPO1 dans la PD ainsi que le taux de RSPO1 lié à la gaine externe de la racine ont augmenté. Dans l'essai clinique, la lotion pour cheveux contenant 2 % d'extrait de cresson a augmenté l'épaisseur et la densité des cheveux, améliorant ainsi les symptômes de perte de cheveux. CONCLUSION: La capacité de l'extrait de cresson à supprimer la sécrétion de DKK1 et à antagoniser DKK1 via la protéine RSPO1 lui a conféré un effet anti-androgénique puissant. Ces résultats ont mis en évidence le potentiel de l'extrait de cresson pour le traitement de la perte de cheveux.

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Palmoplantar keratodermas (PPK) comprise a heterogenous group of acquired and hereditary disorders marked by excessive thickening of the epidermis of palms and soles. Hereditary PPKs can be classified into 3 groups: 1) isolated non-syndromic PPKs; 2) complex non-syndromic PPKs associated with other ectodermal defects; and 3) syndromic PPKs associated with extracutaneous manifestations. All types of inheritance have been observed: autosomal dominant, autosomal recessive, X-linked recessive, and mitochondrial. Some of these disorders are restricted to geographic isolates. This review describes the different genetic causes of hereditary syndromic and complex PPKs for which the genes have been identified. The identification of pathogenic variants has consequences in terms of genetic counseling, appropriate medical care and follow-up, especially for PPKs predisposing to hearing loss, cardiomyopathies, benign tumors or carcinomas. In addition, the development of targeted therapies based on pathophysiology of disorders should allow a more effective treatment of these conditions in the near future.

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Aim: To delineate the association of end-stage renal disease (ESRD) and Wnt-proteins including the agonist R-spondin-1, the transducer ß-catenin and the antagonists DKK1 and sclerostin. Materials & methods: Serum Wnt-pathway proteins levels were measured by ELISA in 60 ESRD patients and 30 normal controls. Results: DKK1 and sclerostin were significantly higher in ESRD than in controls, and ß-catenin and the catenin + R-spondin-1/DKK1 + sclerostin ratio, reflecting the ratio of agonist and transducer on antagonists (AT/ANTA), were significantly lower in ESRD. Estimated glomerular filtration rate was significantly associated with DKK1 and sclerostin (inversely), ß-catenin (positively) and the AT/ANTA ratio (r = 0.468, p < 0.001). Conclusion: Wnt/ß-catenin pathway proteins show significant alterations in ESRD, indicating significantly increased levels of antagonists.

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BACKGROUND: R-spondin 1 (Rspol) and Slit2 have been found to play a vital role in cancer development, and have the potential to act as therapeutic adjuvants to increase tolerance to aggressive chemotherapy and/or radiotherapy. This "proof of concept" study evaluates the role of Rspo1 and Slit2 expression in the clinical outcome of cervical cancer patients. METHODS: Using enzyme linked immunosorbent assays (ELISA), we analyzed Rspo1 and Slit2 levels from patients diagnosed with the International Federation of Gynecology and Obstetrics (FIGO) stage IB1-IIA2 cervical cancer (n=34) who received chemotherapy (CT) and/or radiotherapy (RT) and correlated the data with the acute radiation morbidity scoring criteria. RESULTS: Cervical cancer patients who underwent CT and/or RT showed that neither the level of Rspo1 nor the level of Slit2 changed significantly after the first round of CT (CT1), RT, or the second CT (CT2). However, neurological sensory scores and influence of infection scores were elevated following increasing rounds of therapies. Rspo1 levels correlated negatively with the morbidity score of neutrophils, hemoglobin, platelet, infection score, neurological sensory score, and performance status after CT1, RT, or CT2. We also found that Slit2 levels were negatively correlated with genitourinary, heart, and neurological sensory scores at RT and CT2. CONCLUSIONS: The levels of Rspo1 and Slit2 correlate positively to the tolerance of the patients. In contrast, the levels of Rspo1 and Slit2 showed a negative correlation to the morbidity score of the patients undergoing CT and/or RT. Thus, Rspo1 and Slit2 may be potential predictive biomarkers for patients with cervical cancer receiving CT or RT postoperatively, which supports the current pursuit of the clinical significance of Rspo1 and Slit2.

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Purpose: Our purpose was to investigate the effect of lncRNA MEF2C antisense RNA 1 (MEF2C-AS1) on cervical cancer and further explore its underlying molecular mechanisms. Methods: The proliferation, migration and invasion of CC cells were determined by counting Kit-8 (CCK-8), colony formation assay, and transwell assays, respectively. qRT-PCR and western blot were conducted to quantitatively detect the expression of lncRNA MEF2C-AS1, miR-592 and R-spondin1 (RSPO1). Kaplan-Meier survival curve from the Cancer Genome Atlas (TCGA) database and the Gene Expression Profiling Interactive Analysis (GEPIA) website was used to describe the overall survival. Bioinformatics analysis was performed to search the downstream target of lncRNA MEF2C-AS1 and miR-592. Luciferase reporter assay was conducted to detect the interaction between lncRNA MEF2C-AS1 and miR-592 or miR-592 and RSPO1. Results: The data from GEPIA website showed that lncRNA MEF2C-AS1 expression was down-regulated in CC tissues and also associated with survival rate of CC patients. Moreover, the results of qRT-PCR also showed lncRNA MEF2C-AS1 was lowly expressed in CC cells. Subsequently, we confirmed that overexpression of lncRNA MEF2C-AS1 inhibited the proliferation, migration and invasion of CC cells. Further research illustrated that lncRNA MEF2C-AS1 was the target of miR-592, and RSPO1 was the downstream target gene of miR-592. Importantly, functional research findings indicated that lncRNA MEF2C-AS1 inhibited CC via suppressing miR-592 by targeting RSPO1. Conclusion: In our study, we demonstrated the functional role of the lncRNA MEF2C-AS1-miR-592-RSPO1 axis in the progression of CC, which provides a latent target for CC treatment.

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Ovarian paracrine mediation by components of the wingless-type mouse mammary tumor virus integration site ligands (WNT1 to 11) and their receptors, frizzled family members (FZD1 to 10), has been proposed. Secreted truncated forms of FZD proteins (e.g., secreted frizzled-related protein 4 [SFRP4]) block the action of WNT ligands. Dickkopf-1 (DKK1) is another WNT antagonist, and R-spondin-1 (RSPO1) is one of a group of four secreted proteins that enhance WNT/ß-catenin signaling. Our hypothesis was that granulosa cells signal theca cells (TCs) via SFRP4, DKK1, RSPO1, and WNT secretion to regulate TC differentiation and proliferation. Therefore, in vitro experiments were conducted to study the effects of WNT family member 3A (WNT3A), WNT5A, RSPO1, DKK1, insulin-like growth factor 1 (IGF1), bone morphogenetic protein 7 (BMP7), Indian hedgehog (IHH), and fibroblast growth factor 9 (FGF9) on bovine TC proliferation and steroidogenesis. TCs of large (8 to 20 mm) and small (3 to 6 mm) follicles were collected from bovine ovaries; TC monolayers were established in vitro and treated with various doses of recombinant human WNT3A, WNT5A, RSPO1, DKK1, IGF1, FGF9, BMP7, IHH, and/or ovine luteinizing hormone (LH) in serum-free medium for 48 h. In experiment 1, using LH-treated TC, IGF1, IHH, and WNT3A increased (P < 0.05) cell numbers and androstenedione production, whereas WNT3A and BMP7 inhibited (P < 0.05) progesterone production. In experiment 2, FGF9 blocked (P < 0.05) the WNT3A-induced increase in androstenedione production in LH plus IGF1-treated TC. In experiment 3, RSPO1 further increased (P < 0.05) LH plus IGF1-induced progesterone and androstenedione production. In experiment 4, SFRP4 and DKK1 alone had no significant effect on TC proliferation or progesterone production of large-follicle TC but both blocked the inhibitory effect of WNT5A on androstenedione production. In contrast, DKK1 alone inhibited (P < 0.05) small-follicle TC androstenedione production whereas SFRP4 was without effect. We conclude that the ovarian TC WNT system is functional in cattle, with WNT3A increasing proliferation and androstenedione production of TC.

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Chinese soft-shelled turtle Pelodiscus sinensis is an important aquaculture species in China, the male individual being more valuable in aquaculture because of its larger body size, higher growth rate and less fat compared with females. Understanding the mechanism of ovarian differentiation and development is crucial for the production of mono-sex male offspring. However, little is known about the molecular mechanism underlying turtle ovarian differentiation. Here, we characterized the Rspo1 gene, an upstream regulator of vertebrate female sexual differentiation, in P. sinensis. The messenger RNA of Rspo1 was initially expressed at stage 14, preceding gonadal sex differentiation, and exhibited a sexually dimorphic expression pattern throughout the sex determination and gonadal differentiation periods. Rspo1 was rapidly downregulated during aromatase inhibitor-induced female-to-male sex reversal, which occurred prior to gonadal differentiation. Rspo1 loss of function by RNA interference led to partial female-to-male sex reversal, with masculinized changes in the phenotype of gonads, the distribution of germ cells and the expression of testicular regulators. Collectively, these findings suggest that Rspo1 is necessary for primary female sexual differentiation in P. sinensis. This study demonstrates for the first time the functional role of Rspo1 in reptilian sex determination, and is of fundamental significance for the production of fertile pseudo-female parents and mono-sex male offspring of P.sinensis.

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With a well-understood function in mammals, R-spondin1 (Rspo1) is an important regulator of ovarian development via the Wnt/ß-catenin pathway. Rspo1 deficiency causes retardation of ovarian development in XX fish, and increases Rspo1 function induces femininity and sex reversal in XY fish. In this study, Rspo1 was successfully cloned from loach (Misgurnus anguillicaudatus), and its expression profile was analyzed. The full-length cDNA of Misgurnus anguillicaudatus Rspo1 (MaRspo1) comprised 1322 bp and included an open reading frame (ORF) of 795 bp, which encoded a predicted polypeptide measuring 264 amino acids in length. Phylogenetic and gene structure analyses showed a highly conserved sequence of MaRspo1 (identical to the Rspo1 genes of other species), consisting of an N-terminal signal peptide (SP), two furin-like cysteine-rich domains (FU1 and FU2), a thrombospondin type 1 repeat (TSP1) and a C-terminal region. Real-time PCR revealed the female-biased expression profile of MaRspo1, with the highest expression level among tested tissues detected in ovary. Investigation of MaRspo1 expression levels throughout the early development stage (10-60 days post hatching) under three temperature treatments (25 °C, 28 °C, and 31 °C) revealed significantly differential expression of MaRspo1 among the three temperature groups, with decreased MaRspo1 expression in the high-temperature (31 °C) group. The results of DNA methylation analysis indicated that exposure to high temperature during early development can increase the average promoter methylation level of MaRspo1 in both females and males. Taken together, the results of this study provide the basis for the further investigation of the molecular mechanism of Rspo1 in response to temperature.

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BACKGROUND: R-spondins, including R-spondin 1 (RSPO1), are a family of Wnt ligands that help to activate the canonical Wnt/ß-catenin pathway, which is critical for intestinal epithelial cell proliferation and maintenance of intestinal stem cells. This proliferation underpins the epithelial expansion, or intestinal adaptation (IA), that occurs following massive bowel resection and short bowel syndrome (SBS). The purpose of this study was to identify if recombinant human RSPO1 (rhRSPO1) could be serially administered to SBS zebrafish to enhance cellular proliferation and IA. METHODS: Adult male zebrafish were assigned to four groups: sham + PBS, SBS + PBS, sham + rhRSPO1, and SBS + rhRSPO1. Sham fish had a laparotomy alone. SBS fish had a laparotomy with distal intestinal ligation and creation of a proximal stoma. Fish were weighed at initial surgery and then weekly. rhRSPO1 was administered post-operatively following either a one- or two-week dosing schedule with either 3 or 5 intraperitoneal injections, respectively. Fish were harvested at 7 or 14 days with intestinal segments collected for analysis. RESULTS: Repeated intraperitoneal injection of rhRSPO1 was feasible and well tolerated. At 7 days, intestinal epithelial proliferation was increased by rhRSPO1. At 14 days, SBS + rhRSPO1 fish lost significantly less weight than SBS + PBS fish. Measurements of intestinal surface area were not increased by rhRSPO1 administration but immunofluorescent staining for ß-catenin and gene expression for cyclin D1 was increased. CONCLUSIONS: Intraperitoneal injection of rhRSPO1 decreased weight loss in SBS zebrafish with increased ß-catenin + cells and cyclin D1 expression at 14 days, indicating improved weight maintenance might result from increased activation of the canonical Wnt pathway.

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BACKGROUND/AIM: R-spondins control WNT signaling and RSPO1 and LGR6, two of its receptors, are uniquely expressed at high levels in high-grade serous ovarian cancer (HGSOC). The aim of this study was to assess the interrelations between the expression of the RSPOs and LGRs in HGSOC and in the ovarian surface (OSE) and fallopian tube surface epithelium (FTSE) from which HGSOC arises. MATERIALS AND METHODS: Analysis of TCGA (HGSOC), CCLE (ovary), and other publicly accessed RNA-Seq data using UC San Diego Computational Cancer Analysis Library (CCAL) to perform differential expression analysis, association studies, and gene set inspection using the single-sample GSEA method. Additionally, we employed multiple publicly available databases including StringDB, Human Protein Atlas, and cBioPortal to aid the investigation. RESULTS: Among normal tissues, expression of RSPO1, LGR5 and LGR6 was highest in the fallopian tube. The relative levels of expression of the RSPOs and LGRs in the OSE and FTSE matched those in HGSOC. RSPO1 and LGR6 were highly co-expressed in all three tissues. Gene set enrichment analysis (GSEA) showed that expression of RSPO1 was strongly linked to the enrichment of three separate WNT-driven GO pathways. Analysis of genes that impacted overall survival identified two other immediately adjacent genes that control WNT signaling, KREMEN1 and ZNRF3 whose expression and copy number were coordinately linked. CONCLUSION: RSPO1 and LGR6 are coordinately expressed in HGSOC and the two normal tissues from which this tumor arises, and their expression is linked to WNT signaling pathways known the control cell fate and proliferation.

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Introduction: Cell therapy and tissue engineering has recently emerged as a new option for short bowel syndrome (SBS) treatment, generating tissue engineered small intestine (TESI) from organoid units (OU) and biodegradable scaffolds. The recombinant human R-Spondin 1 (rhRSPO1) protein may be a key player in this process due to its mitogenic activity in intestinal stem cells. Objective: Aiming at optimizing the TESI formation process and advancing this technology closer to the clinic, we evaluated the effects of rhRSPO1 protein on OU culture and TESI formation. Methods: Intestinal OU were isolated from C57BL/6 mice and cultured in Matrigel in the presence or absence of recombinant human rhRSPO1. Throughout the culture, OU growth and survival rates were evaluated, and cells were harvested on day 3. OU were seeded onto biodegradable scaffolds, in the presence or absence of 5 µg of rhRSPO1 and implanted into the omentum of NOD/SCID mice in order to generate TESI. The explants were harvested after 30 days, weighed, fixed in formalin and embedded in paraffin for histological analysis and immunofluorescence for different cell markers. Results: After 3 days, rhRSPO1-treated OU attained a larger size, when compared to the control group, becoming 5.7 times larger on day 6. Increased survival was observed from the second day in culture, with a 2-fold increase in OU survival between days 3 and 6. A 4.8-fold increase of non-phosphorylated ß-catenin and increased relative expression of Lgr5 mRNA in the rhRSPO1-treated group confirms activation of the canonical Wnt pathway and suggests maintenance of the OU stem cell niche and associated stemness. After 30 days of in vivo maturation, rhRSPO1-treated TESI presented a larger mass than constructs treated with saline, developing a more mature intestinal epithelium with well-formed villi and crypts. In addition, the efficiency of OU-loaded rhRSPO1-treated scaffolds significantly increased, forming TESI in 100% of the samples (N = 8), of which 40% presented maximum degree of development, as compared to 66.6% in the control group (N = 9). Conclusion: rhRSPO1 treatment improves the culture of mouse intestinal OU, increasing its size and survival in vitro, and TESI formation in vivo, increasing its mass, degree of development and engraftment.

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BACKGROUND: The R-Spondin proteins comprise a family of secreted proteins, known for their important roles in cell proliferation, differentiation and death, by inducing the Wnt pathway. Several studies have demonstrated the importance of RSPOs in regulation of a number of tissue-specific processes, namely: bone formation, skeletal muscle tissue development, proliferation of pancreatic ß-cells and intestinal stem cells and even cancer. RSPO1 stands out among RSPOs molecules with respect to its potential therapeutic use, especially in the Regenerative Medicine field, due to its mitogenic activity in stem cells. Here, we generated a recombinant human RSPO1 (rhRSPO1) using the HEK293 cell line, obtaining a purified, characterized and biologically active protein product to be used in Cell Therapy. The hRSPO1 coding sequence was synthesized and subcloned into a mammalian cell expression vector. HEK293 cells were stably co-transfected with the recombinant expression vector containing the hRSPO1 coding sequence and a hygromycin resistance plasmid, selected for hygror and subjected to cell clones isolation. RESULTS: rhRSPO1 was obtained, in the absence of serum, from culture supernatants of transfected HEK293 cells and purified using a novel purification strategy, involving two sequential chromatographic steps, namely: heparin affinity chromatography, followed by a molecular exclusion chromatography, designed to yield a high purity product. The purified protein was characterized by Western blotting, mass spectrometry and in vitro (C2C12 cells) and in vivo (BALB/c mice) biological activity assays, confirming the structural integrity and biological efficacy of this human cell expression system. Furthermore, rhRSPO1 glycosylation analysis allowed us to describe, for the first time, the glycan composition of this oligosaccharide chain, confirming the presence of an N-glycosylation in residue Asn137 of the polypeptide chain, as previously described. In addition, this analysis revealing the presence of glycan structures such as terminal sialic acid, N-acetylglucosamine and/or galactose. CONCLUSION: Therefore, a stable platform for the production and purification of recombinant hRSPO1 from HEK293 cells was generated, leading to the production of a purified, fully characterized and biologically active protein product to be applied in Tissue Engineering.

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Leucine-rich repeat-containing G-protein coupled receptor 4 (LGR4) suppresses food intake after its activation by binding of its ligands, R-spondins. We investigated the mechanism of food intake suppression by R-spondin1 in a region-specific Lgr4 gene knockout (LGR4 cKO) mouse model, generated by deletion of the Lgr4 gene in arcuate nucleus (ARC) using Lgr4fx/fx mice combined with infection of an AAV-Cre vector. After R-spondin1 administration, LGR4 cKO mice didn't exhibit a suppressed appetite, compared to that in control mice, which received a vehicle. In ARC of LGR4 cKO mice, Pomc mRNA expression was reduced, leading to suppressed food intake. On the other hand, neurons-specific LGR4 KO mice exhibited no differences in Pomc expression, and no structural differences were observed in the ARC of mutant mice. These results suggest that LGR4 is an essential part of the mechanism, inducing Pomc gene expression with R-spondin1 in ARC neurons in mice, thereby regulating feeding behavior. Abbreviations: LGR4: Leucine-rich repeat-containing G-protein coupled receptor 4; RSPOs: roof plate-specific spondins; ARC: arcuate nucleus; AAV: adeno associated virus; POMC: pro-opiomelanocortin; CART: cocaine and amphetamine-regulated transcript; NPY: neuropeptide Y; AgRP: agouti-related peptide; Axin2: axis inhibition protein 2; Lef1: lymphoid enhancer binding factor 1; ccnd1: cyclin D1.

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Stem cell aging underlies aging-associated disorders, such as steeply increased incidences of tumors and impaired regeneration capacity upon stress. However, whether and how the intestinal stem cells age remains largely unknown. Here we show that intestinal stem cells derived from 24-month-old mice hardly form typical organoids with crypt-villus structures, but rather mainly form big, rounded cysts devoid of differentiated cell types, which mimics the culturing of heterozygous APC-deficient cells from the APCmin mouse line. Further analysis showed that cultured crypts derived from aged mice exhibited reduced expression levels of differentiation genes and higher expression of Wnt target genes. Lowering the concentration of R-spondin-1 in the culture system significantly reduced formation of rounded cysts, accompanied by an increased formation of organoids from crypts derived from old mice. We are the first to uncover that intestinal stem cells derived from old mice harbor significant deficiency in differentiation that can be partially rescued through a reduction in R-spondin-1 exposure. This could be highly relevant to intestinal tumor development and the reduced regeneration potential observed in the aged population. Our study provides the first experimental evidence that an over-responsiveness to Wnt/beta-catenin signaling of aged intestinal stem cells mediates the aging-induced deficiency in differentiation, and could serve as a potential target to ameliorate aging-associated intestinal pathologies.

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Hyperphagia is common in diabetes and may worsen hyperglycemia and diabetic complications. The responsible mechanisms are not well understood. The hypothalamus is a key center for the control of appetite and energy homeostasis. The ventromedial nucleus (VMH) and arcuate nucleus (ARC) are two critical nuclei involved in these processes. We have reported that R-spondin 1 (Rspo1) and its receptor leucin-rich repeat and G protein-coupled receptor 4 (LGR4) in the VMH and ARC suppressed appetite, but the downstream neuronal pathways are unclear. Here we show that neurons containing cocaine and amphetamine-regulated transcript (CART) in ARC express both LGR4 and insulin receptor; intracerebroventricular injection of Rspo1 induced c-Fos expression in CART neurons of ARC; and silencing CART in ARC attenuated the anorexigenic actions of Rspo1. In diabetic and obese fa/fa rats, Rspo1 mRNA in VMH and CART mRNA in ARC were reduced; this was accompanied by increased food consumption. Insulin treatment restored Rspo1 and CART gene expressions and normalized eating behavior. Chronic intracerebroventricular injection of Rspo1 inhibited food intake and normalized diabetic hyperphagia; intracerebroventricular injection of Rspo1 or insulin increased CART mRNA in ARC. In the CART neuron cell line, Rspo1 and insulin potentiated each other on pERK and ß-catenin, and in rats, they acted synergistically to inhibit food intake. Silencing Rspo1 in VMH reduced CART expression in ARC and attenuated the inhibitory effect of insulin on food intake. In conclusion, our data indicated that CART works downstream of Rspo1 and Rspo1 mediated the action of insulin centrally. The altered Rspo1/CART neurocircuit in the hypothalamus contributes to hyperphagia in diabetes. NEW & NOTEWORTHY This study reports that cocaine and amphetamine-regulated transcript (CART) neurons in the arcuate nucleus (ARC) of hypothalamus acted downstream of R-spondin 1 (Rspo1) to inhibit food intake. The Rspo1 mRNA level in ventromedial nucleus (VMH) and CART mRNA level in ARC were reduced in type 1 diabetic rat and obese fa/fa rat. Rspo1 and insulin acted synergistically on phospho-ERK and ß-catenin signal pathways and in suppressing food intake. The current results proposed that altered Rspo1/CART neurocircuit in the hypothalamus contributes to hyperphagia in diabetes.

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