RESUMEN

Background: Endogenous insulin supplementation is essential for individuals with type 1 diabetes (T1D). However, current treatments, including pancreas transplantation, insulin injections, and oral medications, have significant limitations. The development of engineered cells that can secrete endogenous insulin offers a promising new therapeutic strategy for type 1 diabetes (T1D). This approach could potentially circumvent autoimmune responses associated with the transplantation of differentiated ß-cells or systemic delivery of viral vectors. Methods: We utilized CRISPR/Cas9 gene editing coupled with homology-directed repair (HDR) to precisely integrate a promoter-free EMCVIRES-insulin cassette into the 3' untranslated region (UTR) of the GAPDH gene in human HEK-293T cells. Subsequently quantified insulin expression levels in these engineered cells, the viability and functionality of the engineered cells when seeded on different cell vectors (GelMA and Cytopore I) were also assessed. Finally, we investigated the therapeutic potential of EMCVIRES-based insulin secretion circuits in reversing Hyperglycaemia in T1D mice. Result: Our results demonstrate that HDR-mediated gene editing successfully integrated the IRES-insulin loop into the genome of HEK-293T cells, a non-endocrine cell line, enabling the expression of human-derived insulin. Furthermore, Cytopore I microcarriers facilitated cell attachment and proliferation during in vitro culture and enhanced cell survival post-transplantation. Transplantation of these cell-laden microcarriers into mice led to the development of a stable, fat-encapsulated structure. This structure exhibited the expression of the platelet-endothelial cell adhesion molecule CD31, and no significant immune rejection was observed throughout the experiment. Diabetic mice that received the cell carriers reversed hyperglycemia, and blood glucose fluctuations under simulated feeding stimuli were very similar to those of healthy mice. Conclusion: In summary, our study demonstrates that Cytopore I microcarriers are biocompatible and promote long-term cell survival in vivo. The promoter-free EMCVIRES-insulin loop enables non-endocrine cells to secrete mature insulin, leading to a rapid reduction in glucose levels. We have presented a novel promoter-free genetic engineering strategy for insulin secretion and proposed an efficient cell transplantation method. Our findings suggest the potential to expand the range of cell sources available for the treatment of diabetes, offering new avenues for therapeutic interventions.

Asunto(s)

Diabetes Mellitus Tipo 1 , Edición Génica , Hiperglucemia , Células Secretoras de Insulina , Insulina , Humanos , Animales , Hiperglucemia/terapia , Hiperglucemia/metabolismo , Ratones , Células Secretoras de Insulina/metabolismo , Insulina/metabolismo , Insulina/genética , Células HEK293 , Diabetes Mellitus Tipo 1/terapia , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 1/genética , Edición Génica/métodos , Diabetes Mellitus Experimental/terapia , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/genética , Sitios Internos de Entrada al Ribosoma/genética , Regiones Promotoras Genéticas , Sistemas CRISPR-Cas

RESUMEN

The insulin-linked polymorphic region is a variable number of tandem repeats region of DNA in the promoter of the insulin gene that regulates transcription of insulin. This region is known to form the alternative DNA structures, i-motifs and G-quadruplexes. Individuals have different sequence variants of tandem repeats and although previous work investigated the effects of some variants on G-quadruplex formation, there is not a clear picture of the relationship between the sequence diversity, the DNA structures formed, and the functional effects on insulin gene expression. Here we show that different sequence variants of the insulin linked polymorphic region form different DNA structures in vitro. Additionally, reporter genes in cellulo indicate that insulin expression may change depending on which DNA structures form. We report the crystal structure and dynamics of an intramolecular i-motif, which reveal sequences within the loop regions forming additional stabilising interactions that are critical to formation of stable i-motif structures. The outcomes of this work reveal the detail in formation of stable i-motif DNA structures, with potential for rational based drug design for compounds to target i-motif DNA.

Asunto(s)

ADN , G-Cuádruplex , Insulina , Regiones Promotoras Genéticas , Insulina/química , Insulina/genética , ADN/química , ADN/genética , Humanos , Conformación de Ácido Nucleico , Motivos de Nucleótidos , Cristalografía por Rayos X , Polimorfismo Genético , Secuencias Repetidas en Tándem/genética , Secuencia de Bases , Modelos Moleculares , Animales , Genes Reporteros

RESUMEN

BACKGROUND/AIM: Although studies on senescence-related genes using human islets of Langerhans have been performed, the expression of senescence-related genes and their association with functional genes in islets remain insufficiently investigated. We aimed to determine whether and what types of senescent-related genes are expressed in islets and identify their correlations with pancreatic function-related genes by using islets isolated for transplantation from individuals of various ages. MATERIALS AND METHODS: Islets from deceased donors of both sexes and different ages were used for analysis. The expression status of senescence-related genes (glutaminase 1, interleukin 6, interleukin 8, cyclin-dependent kinase inhibitor 2A, cyclin-dependent kinase inhibitor 1A, and senescence-associated beta-galactosidase) and pancreatic function-related genes (glucagon and insulin) was examined by reverse transcription-quantitative polymerase chain reaction, and their relationships with age were investigated. RESULTS: We obtained isolated human islets from 18 deceased multiorgan donors. There was no correlation between donor age and expression of any of the senescence-related genes. Regarding correlations between donor age and pancreatic function-related genes, age was positively correlated only with INS (r=0.49, p=0.03). INS expression was not correlated with that of GLS1 (r=0.23, p=0.34), IL6 (r=-0.06, p=0.79), or IL8 (r=-0.1, p=0.12), but positively related with p16 (r=0.89, p<0.0001), p21 (r=0.51, p=0.02), and SA-ß-gal (r=0.52, p=0.02). CONCLUSION: We showed the functional potential even of aged islets, which were originally thought to be functionally impaired. We were unable to identify any senescence-related genes expressed in islets from donors of different ages. Therefore, a new index is needed to evaluate not only actual chronological age but also organ- and cell-specific age.

Asunto(s)

Senescencia Celular , Islotes Pancreáticos , Donantes de Tejidos , Humanos , Islotes Pancreáticos/metabolismo , Femenino , Masculino , Adulto , Persona de Mediana Edad , Senescencia Celular/genética , Anciano , Envejecimiento/genética , Adulto Joven , Regulación de la Expresión Génica , Factores de Edad , Insulina/metabolismo , Insulina/genética

RESUMEN

PF11_0189 is a putative insulin degrading enzyme present in Plasmodium falciparum genome. The catalytic domain of PF11_0189 is about 27 kDa. Substrate specificity study shows PF11_0189 acts upon different types of proteins. The substrate specificity is found to be highest when insulin is used as a substrate. Metal dependency study shows highest dependency of PF11_0189 towards zinc metal for its proteolytic activity. Chelation of zinc metal with EDTA shows complete absence of PF11_0189 activity. Peptide inhibitors, P-70 and P-121 from combinatorial peptide library prepared against PF11_0189 show inhibition with an IC50 value of 4.8 µM and 7.5 µM respectively. A proven natural anti-malarial peptide cyclosporin A shows complete inhibition against PF11_0189 with an IC50 value of 0.75 µM suggesting PF11_0189 as a potential target for peptide inhibitors. The study implicates that PF11_0189 is a zinc metalloprotease involved in catalysis of insulin. The study gives a preliminary insight into the mechanism of complications arising from glucose abnormalities during severe malaria.

Asunto(s)

Insulisina , Plasmodium falciparum , Proteínas Protozoarias , Plasmodium falciparum/enzimología , Plasmodium falciparum/genética , Insulisina/genética , Insulisina/química , Insulisina/metabolismo , Proteínas Protozoarias/genética , Proteínas Protozoarias/química , Proteínas Protozoarias/metabolismo , Especificidad por Sustrato , Insulina/química , Insulina/metabolismo , Insulina/genética , Zinc/química , Zinc/metabolismo , Genoma de Protozoos , Proteínas Recombinantes/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/aislamiento & purificación , Expresión Génica , Clonación Molecular , Antimaláricos/química , Antimaláricos/farmacología , Ciclosporina/química , Ciclosporina/farmacología

RESUMEN

The increased prevalence of diabetes and the growing popularity of non-invasive methods of recombinant human insulin uptake, such as oral insulin, have increased insulin demand, further limiting the affordability of insulin. Over 40 years have passed since the development of engineered microorganisms that replaced the animal pancreas as the primary source of insulin. To stay ahead of the need for insulin in the present and the future, a few drawbacks with the existing expression systems need to be alleviated, including the inclusion body formation, the use of toxic inducers, and high process costs. To address these bottlenecks and improve insulin production, a variety of techniques are being used in bacteria, yeasts, transgenic plants and animals, mammalian cell lines, and cell-free expression systems. Different approaches for the production of insulin, including two-chain, proinsulin or mini-proinsulin, preproinsulin coupled with fusion protein, chaperone, signal peptide, and purification tags, are explored in upstream, whereas downstream processing takes into account the recovery of intact protein in its bioactive form and purity. This article focuses on the strategies used in the upstream and downstream phases of the bioprocess to produce recombinant human insulin. This review also covers a range of analytical methods and tools employed in investigating the genuity of recombinant human insulin.

Asunto(s)

Insulina , Proteínas Recombinantes , Humanos , Insulina/genética , Insulina/metabolismo , Insulina/biosíntesis , Proteínas Recombinantes/genética , Proteínas Recombinantes/biosíntesis , Animales

RESUMEN

Amyloid polymorphism is a hallmark of almost all amyloid species, yet the mechanisms underlying the formation of amyloid polymorphs and their complex architectures remain elusive. Commonly, two main mesoscopic topologies are found in amyloid polymorphs characterized by non-zero Gaussian and mean curvatures: twisted ribbons and helical fibrils, respectively. Here, a rich heterogeneity of configurations is demonstrated on insulin amyloid fibrils, where protofilament packing can occur, besides the common polymorphs, also in a combined mode forming mixed-curvature polymorphs. Through AFM statistical analysis, an extended array of heterogeneous architectures that are rationalized by mesoscopic theoretical arguments are identified. Notably, an unusual fibrillization pathway is also unraveled toward mixed-curvature polymorphs via the widespread recruitment and intertwining of protofilaments and protofibrils. The results present an original view of amyloid polymorphism and advance the fundamental understanding of the fibrillization mechanism from single protofilaments into mature amyloid fibrils.

Asunto(s)

Amiloide , Amiloide/química , Amiloide/metabolismo , Microscopía de Fuerza Atómica/métodos , Insulina/química , Insulina/metabolismo , Insulina/genética

RESUMEN

Parent-of-origin-specific expression of imprinted genes is critical for successful mammalian growth and development. Insulin, coded by the INS gene, is an important growth factor expressed from the paternal allele in the yolk sac placenta of therian mammals. The tyrosine hydroxylase gene TH encodes an enzyme involved in dopamine synthesis. TH and INS are closely associated in most vertebrates, but the mouse orthologues, Th and Ins2, are separated by repeated DNA. In mice, Th is expressed from the maternal allele, but the parental origin of expression is not known for any other mammal so it is unclear whether the maternal expression observed in the mouse represents an evolutionary divergence or an ancestral condition. We compared the length of the DNA segment between TH and INS across species and show that separation of these genes occurred in the rodent lineage with an accumulation of repeated DNA. We found that the region containing TH and INS in the tammar wallaby produces at least five distinct RNA transcripts: TH, TH-INS1, TH-INS2, lncINS and INS. Using allele-specific expression analysis, we show that the TH/INS locus is expressed from the paternal allele in pre- and postnatal tammar wallaby tissues. Determining the imprinting pattern of TH/INS in other mammals might clarify if paternal expression is the ancestral condition which has been flipped to maternal expression in rodents by the accumulation of repeat sequences.

Asunto(s)

Alelos , Impresión Genómica , Insulina , Mamíferos , Tirosina 3-Monooxigenasa , Animales , Mamíferos/genética , Tirosina 3-Monooxigenasa/genética , Ratones/genética , Insulina/genética , Insulina/metabolismo , Macropodidae/genética , Femenino , Masculino

RESUMEN

Receptor tyrosine kinases (RTKs) mediate the actions of growth factors in metazoans. In decapod crustaceans, RTKs are implicated in various physiological processes, such molting and growth, limb regeneration, reproduction and sexual differentiation, and innate immunity. RTKs are organized into two main types: insulin receptors (InsRs) and growth factor receptors, which include epidermal growth factor receptor (EGFR), fibroblast growth factor receptor (FGFR), vascular endothelial growth factor receptor (VEGFR), and platelet-derived growth factor receptor (PDGFR). The identities of crustacean RTK genes are incomplete. A phylogenetic analysis of the CrusTome transcriptome database, which included all major crustacean taxa, showed that RTK sequences segregated into receptor clades representing InsR (72 sequences), EGFR (228 sequences), FGFR (129 sequences), and PDGFR/VEGFR (PVR; 235 sequences). These four receptor families were distinguished by the domain organization of the extracellular N-terminal region and motif sequences in the protein kinase catalytic domain in the C-terminus or the ligand-binding domain in the N-terminus. EGFR1 formed a single monophyletic group, while the other RTK sequences were divided into subclades, designated InsR1-3, FGFR1-3, and PVR1-2. In decapods, isoforms within the RTK subclades were common. InsRs were characterized by leucine-rich repeat, furin-like cysteine-rich, and fibronectin type 3 domains in the N-terminus. EGFRs had leucine-rich repeat, furin-like cysteine-rich, and growth factor IV domains. N-terminal regions of FGFR1 had one to three immunoglobulin-like domains, whereas FGFR2 had a cadherin tandem repeat domain. PVRs had between two and five immunoglobulin-like domains. A classification nomenclature of the four RTK classes, based on phylogenetic analysis and multiple sequence alignments, is proposed.

Asunto(s)

Furina , Insulina , Furina/genética , Filogenia , Insulina/genética , Transcriptoma , Cisteína , Leucina/genética , Factor A de Crecimiento Endotelial Vascular/genética , Proteínas Tirosina Quinasas Receptoras/genética , Proteínas Tirosina Quinasas Receptoras/metabolismo , Receptores ErbB/metabolismo , Receptores de Factores de Crecimiento de Fibroblastos/genética , Receptores de Factores de Crecimiento de Fibroblastos/metabolismo , Perfilación de la Expresión Génica , Tirosina

RESUMEN

Monogenic diabetes caused by changes in the gene that encodes insulin (INS) is a very rare form of monogenic diabetes (<1%). The aim of this work is to describe the clinical and glycaemic control characteristics over time from four members of a family diagnosed with monogenic diabetes with the novel mutation: c.206del,p.(Gly69Aalfs*62) located in exon 3 of the gene INS. 75% are females, with debut in adolescence and negative autoimmunity. In all cases, C-peptide is detectable decades after diagnosis (>0.6ng/ml). Currently, patients are being treated either with insulin in a bolus-basal regimen, oral antidiabetics or hybrid closed loop system. Monogenic diabetes due to mutation in the INS is an entity with heterogeneous presentation, whose diagnosis requires high suspicion and presents an important clinical impact. Given the lack of standards in this regard, therapy must be individualized, although insulin therapy could help preserve beta cell functionality in these subjects.

Asunto(s)

Diabetes Mellitus , Adolescente , Femenino , Humanos , Masculino , Autoinmunidad , Diabetes Mellitus/diagnóstico , Hipoglucemiantes/uso terapéutico , Insulina/genética , Mutación

RESUMEN

Many insulin gene variants alter the protein sequence and result in monogenic diabetes due to insulin insufficiency. However, the molecular mechanisms of various disease-causing mutations are unknown. Insulin is synthesized as preproinsulin containing a signal peptide (SP). SPs of secreted proteins are recognized by the signal recognition particle (SRP) or by another factor in a SRP-independent pathway. If preproinsulin uses SRP-dependent or independent pathways is still debatable. We demonstrate by the use of site-specific photocrosslinking that the SRP subunit, SRP54, interacts with the preproinsulin SP. Moreover, SRP54 depletion leads to the decrease of insulin mRNA and protein expression, supporting the involvement of the RAPP protein quality control in insulin biogenesis. RAPP regulates the quality of secretory proteins through degradation of their mRNA. We tested five disease-causing mutations in the preproinsulin SP on recognition by SRP and on their effects on mRNA and protein levels. We demonstrate that the effects of mutations are associated with their position in the SP and their severity. The data support diverse molecular mechanisms involved in the pathogenesis of these mutations. We show for the first time the involvement of the RAPP protein quality control pathway in insulin biogenesis that is implicated in the development of neonatal diabetes caused by the Leu13Arg mutation.

Asunto(s)

Insulina , Precursores de Proteínas , Estabilidad del ARN , Partícula de Reconocimiento de Señal , Humanos , Recién Nacido , Diabetes Mellitus , Insulina/genética , Insulina/metabolismo , Precursores de Proteínas/metabolismo , Señales de Clasificación de Proteína/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Partícula de Reconocimiento de Señal/metabolismo

RESUMEN

Diabetes mellitus is a chronic metabolic disorder marked by hyperglycemia and systemic complications, including hepatic dysfunction, significantly contributing to disease progression and morbidity. This article reviews recent advances in gene-based therapeutic strategies targeting hepatic complications in diabetes, offering a promising approach for precision medicine by addressing underlying molecular mechanisms. Traditional treatments for hepatic complications in diabetes often manage symptoms rather than molecular causes, showing limited efficacy. Gene-based therapies are poised to correct dysfunctional pathways and restore hepatic function. Fundamental gene therapy approaches include gene silencing via small interfering RNAs (siRNAs) to target hepatic glucose production, lipid metabolism, and inflammation. Viral vectors can restore insulin sensitivity and reduce oxidative stress in diabetic livers. Genome editing, especially CRISPR-Cas9, allows the precise modification of disease-associated genes, offering immense potential for hepatic complication treatment. Strategies using CRISPR-Cas9 to enhance insulin receptor expression and modulate aberrant lipid regulatory genes are explored. Safety challenges in gene-based therapies, such as off-target effects and immune responses, are discussed. Advances in nanoparticle-based delivery systems and targeted gene editing techniques offer solutions to enhance specificity and minimize adverse effects. In conclusion, gene-based therapeutic approaches are a transformative direction in managing hepatic complications in diabetes. Further research is needed to optimize efficacy, safety, and long-term outcomes. Nevertheless, these innovative strategies promise to improve the lives of individuals with diabetes by addressing hepatic dysfunction's genetic root causes.

Asunto(s)

Sistemas CRISPR-Cas , Diabetes Mellitus , Humanos , Edición Génica/métodos , Diabetes Mellitus/genética , Insulina/genética

RESUMEN

OBJECTIVE: Heterozygous coding sequence mutations of the INS gene are a cause of permanent neonatal diabetes (PNDM), requiring insulin therapy similar to T1D. While the negative effects on insulin processing and secretion are known, how dominant insulin mutations result in a continued decline of beta cell function after birth is not well understood. METHODS: We explored the causes of beta cell failure in two PNDM patients with two distinct INS mutations using patient-derived iPSCs and mutated hESCs. RESULTS: we detected accumulation of misfolded proinsulin and impaired proinsulin processing in vitro, and a dominant-negative effect of these mutations on beta-cell mass and function after transplantation into mice. In addition to anticipated ER stress, we found evidence of beta-cell dedifferentiation, characterized by an increase of cells expressing both Nkx6.1 and ALDH1A3, but negative for insulin and glucagon. CONCLUSIONS: These results highlight a novel mechanism, the loss of beta cell identity, contributing to the loss and functional failure of human beta cells with specific insulin gene mutations.

Asunto(s)

Diabetes Mellitus , Insulina , Humanos , Animales , Ratones , Insulina/genética , Proinsulina/genética , Diabetes Mellitus/genética , Mutación/genética , Insulina Regular Humana/genética

RESUMEN

AIM: To assess the sex- and time-specific causal effects of obesity-related anthropometric traits on glycaemic traits. MATERIALS AND METHODS: We used univariate and multivariate Mendelian randomization to assess the causal associations of anthropometric traits (gestational variables, birth weight, childhood body mass index [BMI], BMI, waist-to-hip ratio [WHR], BMI-adjusted WHR [WHRadj BMI]) with fasting glucose and insulin in Europeans from the Early Growth Genetics Consortium (n ≤ 298 142), the UK Biobank, the Genetic Investigation of Anthropometric Traits Consortium (n ≤ 697 734; females: n ≤ 434 794; males: n ≤ 374 754) and the Meta-Analyses of Glucose and Insulin-related traits Consortium (n ≤ 151 188; females: n ≤ 73 089; males: n ≤ 67 506), adjusting for maternal genetic effects, smoking, alcohol consumption, and age at menarche. RESULTS: We observed a null association for gestational variables, a negative association for birth weight, and positive associations for childhood BMI and adult traits (BMI, WHR, and WHRadj BMI). In female participants, increased birth weight causally decreased fasting insulin (betaIVW , -0.07, 95% confidence interval [CI] -0.11 to -0.03; p = 1.92 × 10-3 ), but not glucose levels, which was annulled by adjusting for age at menarche. In male participants, increased birth weight causally decreased fasting glucose (betainverse-variance-weighted (IVW) , -0.07, 95% CI -0.11 to -0.03; p = 3.22 × 10-4 ), but not insulin levels. In time-specific analyses, independent effects of birth weight were absent in female participants, and were more pronounced in male participants. Independent effects of childhood BMI were attenuated in both sexes; independent effects of adult traits differed by sex. CONCLUSIONS: Our findings provide evidence for causal and independent effects of sex- and time-specific anthropometric traits on glycaemic variables, and highlight the importance of considering multiple obesity exposures at different time points in the life course.

Asunto(s)

Análisis de la Aleatorización Mendeliana , Obesidad , Adulto , Humanos , Masculino , Femenino , Peso al Nacer/genética , Obesidad/epidemiología , Obesidad/genética , Obesidad/complicaciones , Índice de Masa Corporal , Insulina/genética , Glucosa , Estudio de Asociación del Genoma Completo , Polimorfismo de Nucleótido Simple

RESUMEN

Cone snails possess a diverse array of novel peptide toxins, which selectively target ion channels and receptors in the nervous and cardiovascular systems. These numerous novel peptide toxins are a valuable resource for future marine drug development. In this review, we compared and analyzed the sequence diversity, three-dimensional structural variations, and evolutionary aspects of venom insulin derived from different cone snail species. The comparative analysis reveals that there are significant variations in the sequences and three-dimensional structures of venom insulins from cone snails with different feeding habits. Notably, the venom insulin of some piscivorous cone snails exhibits a greater similarity to humans and zebrafish insulins. It is important to emphasize that these venom insulins play a crucial role in the predatory strategies of these cone snails. Furthermore, a phylogenetic tree was constructed to trace the lineage of venom insulin sequences, shedding light on the evolutionary interconnections among cone snails with diverse diets.

Asunto(s)

Insulina , Ponzoñas , Humanos , Animales , Insulina/genética , Filogenia , Pez Cebra , Evolución Biológica

RESUMEN

Obesity and diabetes are a problem of modern medicine. Although the environmental factors contributing to the development of these diseases are widely known, research into genetic factors is still ongoing. At the same time, the role of inflammation in the pathophysiology of obesity and diabetes is increasingly emphasized. Therefore, the purpose of this study was to investigate the influence of two selected polymorphisms (rs1800795 and rs3842729) on the development of obesity and type 2 diabetes. In this study, 118 participants were examined, including a control group (nonobese and nondiabetic group), an obese group, and a diabetic group. Genotype analysis was performed using the PCR-RFLP method. It has been shown that in patients with the G/G genotype within the rs1800795 polymorphism (IL6), the chance of developing type 2 diabetes is several times lower compared to patients with the G/C and C/C genotypes. However, the rs3842729 polymorphism (INS) does not directly affect the risk of obesity or type 2 diabetes (T2D), although elevated insulin concentrations have been observed in obese and diabetic patients. These results confirm the impact of the rs1800795 polymorphism on the development of diabetes; however, this relationship is more complex and requires further research on other factors.

Asunto(s)

Diabetes Mellitus Tipo 2 , Insulina , Interleucina-6 , Obesidad , Humanos , Diabetes Mellitus Tipo 2/genética , Glucagón , Insulina/genética , Interleucina-6/genética , Obesidad/genética , Polimorfismo de Nucleótido Simple

RESUMEN

Since the first administration of insulin to a person with diabetes in 1922, scientific contributions from academia and industry have improved insulin therapy and access. The pharmaceutical need for insulin is now more than 40 tons annually, half of which is produced by recombinant secretory expression in Saccharomyces cerevisiae. We discuss how, in this yeast species, adaptation of insulin precursors by removable structural elements is pivotal for efficient secretory expression. The technologies reviewed have been implemented at industrial scale and are seminal for the supply of human insulin and insulin analogues to people with diabetes now and in the future. Engineering of a target protein with removable structural elements may provide a general approach to yield optimisation.

Asunto(s)

Diabetes Mellitus , Saccharomyces cerevisiae , Humanos , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Insulina/genética , Proteínas Recombinantes/metabolismo

RESUMEN

During the pathogenesis of type 1 diabetes (T1D) and type 2 diabetes (T2D), pancreatic islets, especially the ß cells, face significant challenges. These insulin-producing cells adopt a regeneration strategy to compensate for the shortage of insulin, but the exact mechanism needs to be defined. High-fat diet (HFD) and streptozotocin (STZ) treatment are well-established models to study islet damage in T2D and T1D respectively. Therefore, we applied these two diabetic mouse models, triggered at different ages, to pursue the cell fate transition of islet ß cells. Cre-LoxP systems were used to generate islet cell type-specific (α, ß, or δ) green fluorescent protein (GFP)-labeled mice for genetic lineage tracing, thereinto ß-cell GFP-labeled mice were tamoxifen induced. Single-cell RNA sequencing (scRNA-seq) was used to investigate the evolutionary trajectories and molecular mechanisms of the GFP-labeled ß cells in STZ-treated mice. STZ-induced diabetes caused extensive dedifferentiation of ß cells and some of which transdifferentiated into a or δ cells in both youth- and adulthood-initiated mice while this phenomenon was barely observed in HFD models. ß cells in HFD mice were expanded via self-replication rather than via transdifferentiation from α or δ cells, in contrast, α or δ cells were induced to transdifferentiate into ß cells in STZ-treated mice (both youth- and adulthood-initiated). In addition to the re-dedifferentiation of ß cells, it is also highly likely that these "α or δ" cells transdifferentiated from pre-existing ß cells could also re-trans-differentiate into insulin-producing ß cells and be beneficial to islet recovery. The analysis of ScRNA-seq revealed that several pathways including mitochondrial function, chromatin modification, and remodeling are crucial in the dynamic transition of ß cells. Our findings shed light on how islet ß cells overcome the deficit of insulin and the molecular mechanism of islet recovery in T1D and T2D pathogenesis.

Asunto(s)

Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 1 , Diabetes Mellitus Tipo 2 , Células Secretoras de Insulina , Islotes Pancreáticos , Ratones , Animales , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 1/genética , Islotes Pancreáticos/metabolismo , Células Secretoras de Insulina/metabolismo , Insulina/genética , Modelos Animales de Enfermedad , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patología

RESUMEN

AIM: To investigate the sex-specific causality of body compositions in type 2 diabetes and related glycaemic traits using Mendelian randomization (MR). MATERIALS AND METHODS: We leveraged sex-specific summary-level statistics from genome-wide association studies for three adipose deposits adjusted for body mass index and height, including abdominal subcutaneous adipose tissue, visceral adipose tissue (VATadj) and gluteofemoral adipose tissue (GFATadj), measured by MRI (20 038 women; 19 038 men), and fat mass-adjusted appendicular lean mass (ALMadj) (244 730 women; 205 513 men) in the UK Biobank. Sex-specific statistics of type 2 diabetes were from the Diabetes Genetics Replication and Meta-analysis Consortium and those for fasting glucose and insulin were from the Meta-analyses of Glucose and Insulin-related Traits Consortium. Univariable and multivariable MR (MVMR) were performed. We also performed MR analyses of anthropometric traits and genetic association analyses using individual-level data of body composition as validation. RESULTS: Univariable MR analysis showed that, in women, higher GFATadj and ALMadj exerted a causally protective effect on type 2 diabetes (GFATadj: odds ratio [OR] 0.59, 95% confidence interval [CI; 0.50, 0.69]; ALMadj: OR 0.84, 95% CI [0.77, 0.91]) and VATadj to be riskier in glycaemic traits. MVMR showed that GFATadj retained a robust effect on type 2 diabetes (OR 0.57, 95% CI [0.42, 0.77]; P = 2.6 × 10-4 ) in women, while it was nominally significant in men (OR 0.58, 95% CI [0.35, 0.96]; P = 3.3 × 10-2 ), after adjustment for ASATadj and VATadj. MR analyses of anthropometric measures and genetic association analyses of glycaemic traits confirmed the results. CONCLUSIONS: Body composition has a sex-specific effect on type 2 diabetes, and higher GFATadj has an independent protective effect on type 2 diabetes in both sexes.

Asunto(s)

Diabetes Mellitus Tipo 2 , Masculino , Humanos , Femenino , Diabetes Mellitus Tipo 2/epidemiología , Diabetes Mellitus Tipo 2/genética , Análisis de la Aleatorización Mendeliana , Estudio de Asociación del Genoma Completo , Índice de Masa Corporal , Adiposidad/genética , Insulina/genética , Imagen por Resonancia Magnética , Glucosa , Polimorfismo de Nucleótido Simple , Estudios Observacionales como Asunto

RESUMEN

BACKGROUND: In vitro and in vivo studies have shown that certain cytokines and hormones may play a role in the development and progression of type 2 diabetes (T2D). However, studies on their role in T2D in humans are scarce. We evaluated associations between 11 circulating cytokines and hormones with T2D among a population of sub-Saharan Africans and tested for causal relationships using Mendelian randomization (MR) analyses. METHODS: We used logistic regression analysis adjusted for age, sex, body mass index, and recruitment country to regress levels of 11 cytokines and hormones (adipsin, leptin, visfatin, PAI-1, GIP, GLP-1, ghrelin, resistin, IL-6, IL-10, IL-1RA) on T2D among Ghanaians, Nigerians, and Kenyans from the Africa America Diabetes Mellitus study including 2276 individuals with T2D and 2790 non-T2D individuals. Similar linear regression models were fitted with homeostatic modelling assessments of insulin sensitivity (HOMA-S) and ß-cell function (HOMA-B) as dependent variables among non-T2D individuals (n = 2790). We used 35 genetic variants previously associated with at least one of these 11 cytokines and hormones among non-T2D individuals as instrumental variables in univariable and multivariable MR analyses. Statistical significance was set at 0.0045 (0.05/11 cytokines and hormones). RESULTS: Circulating GIP and IL-1RA levels were associated with T2D. Nine of the 11 cytokines and hormones (exceptions GLP-1 and IL-6) were associated with HOMA-S, HOMA-B, or both among non-T2D individuals. Two-stage least squares MR analysis provided evidence for a causal effect of GIP and IL-RA on HOMA-S and HOMA-B in multivariable analyses (GIP ~ HOMA-S ß = - 0.67, P-value = 1.88 × 10-6 and HOMA-B ß = 0.59, P-value = 1.88 × 10-5; IL-1RA ~ HOMA-S ß = - 0.51, P-value = 8.49 × 10-5 and HOMA-B ß = 0.48, P-value = 5.71 × 10-4). IL-RA was partly mediated via BMI (30-34%), but GIP was not. Inverse variance weighted MR analysis provided evidence for a causal effect of adipsin on T2D (multivariable OR = 1.83, P-value = 9.79 × 10-6), though these associations were not consistent in all sensitivity analyses. CONCLUSIONS: The findings of this comprehensive MR analysis indicate that circulating GIP and IL-1RA levels are causal for reduced insulin sensitivity and increased ß-cell function. GIP's effect being independent of BMI suggests that circulating levels of GIP could be a promising early biomarker for T2D risk. Our MR analyses do not provide conclusive evidence for a causal role of other circulating cytokines in T2D among sub-Saharan Africans.

Asunto(s)

Diabetes Mellitus Tipo 2 , Polipéptido Inhibidor Gástrico , Resistencia a la Insulina , Proteína Antagonista del Receptor de Interleucina 1 , Humanos , Pueblo Africano , Glucemia , Factor D del Complemento/genética , Diabetes Mellitus Tipo 2/complicaciones , Estudio de Asociación del Genoma Completo , Ghana , Péptido 1 Similar al Glucagón , Insulina/genética , Resistencia a la Insulina/genética , Proteína Antagonista del Receptor de Interleucina 1/genética , Interleucina-6/genética , Kenia , Análisis de la Aleatorización Mendeliana , Factores de Riesgo , Nigeria , Polipéptido Inhibidor Gástrico/genética

RESUMEN

Type 1 diabetes mellitus (T1D) is an autoimmune disease caused by the destruction of insulin-producing ß-cells in the pancreas by cytotoxic T-cells. To date, there are no drugs that can prevent the development of T1D. Insulin replacement therapy is the standard care for patients with T1D. This treatment is life-saving, but is expensive, can lead to acute and long-term complications, and results in reduced overall life expectancy. This has stimulated the research and development of alternative treatments for T1D. In this review, we consider potential therapies for T1D using cellular regenerative medicine approaches with a focus on CRISPR/Cas-engineered cellular products. However, CRISPR/Cas as a genome editing tool has several drawbacks that should be considered for safe and efficient cell engineering. In addition, cellular engineering approaches themselves pose a hidden threat. The purpose of this review is to critically discuss novel strategies for the treatment of T1D using genome editing technology. A well-designed approach to ß-cell derivation using CRISPR/Cas-based genome editing technology will significantly reduce the risk of incorrectly engineered cell products that could behave as a "Trojan horse".

Asunto(s)

Diabetes Mellitus Tipo 1 , Humanos , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/terapia , Sistemas CRISPR-Cas/genética , Edición Génica/métodos , Insulina/genética , Tratamiento Basado en Trasplante de Células y Tejidos