RESUMEN

This case report details the identification of a novel likely pathogenic splicing variant in the TTN gene, associated with dilated cardiomyopathy (DCM), in a 42-year-old male patient presenting with early-onset heart failure and reduced ejection fraction. DCM is a nonischemic heart condition characterized by left biventricular dilation and systolic dysfunction, with approximately one-third of cases being familial and often linked to genetic mutations. The TTN gene, encoding the largest human protein essential for muscle contraction and sarcomere structure, is implicated in about 25% of DCM cases through mutations, especially truncating variants. Our investigation revealed a previously unreported G > C mutation at the splice acceptor site in intron 356 of TTN, confirmed by Sanger sequencing and not found in population databases, suggesting a novel contribution to the understanding of DCM etiology. The case emphasizes the critical role of the TTN gene in cardiac function and the genetic complexity underlying DCM. A comprehensive literature review highlighted the prevalence and significance of splice variants in the TTN gene, particularly those affecting the titin A-band, which is known for its role in muscle contraction and stability. This variant's identification underscores the importance of genetic screening in patients with DCM, offering insights into the disease's familial transmission and potential therapeutic targets. Our findings contribute to the expanding knowledge of genetic factors in DCM, demonstrating the necessity of integrating genetic diagnostics in cardiovascular medicine. This case supports the growing evidence linking splicing mutations in specific regions of the TTN gene to DCM development and underscores the importance of genetic counseling and testing in managing heart disease.

RESUMEN

One of the hallmarks of cancer is the expansion and accumulation of highly immunosuppressive myeloid cells known as myeloid-derived suppressor cells (MDSCs). To study MDSCs biology, differentiation from hematopoietic progenitor cells (HPC) is an useful tool to elucidate the biological and biochemical mechanisms associated with acquisition of immune suppressive activity and expansion in cancer. Although this is one of the protocols performed to study immune suppressive myeloid cells, differentiation of MDSCs from HPC is a method that allows to modify conditions of the supernatants used. In this protocol, we outline the process of differentiating HPCs into MDSCs in vitro using tumor explant supernatants to recapitulate the tumor microenvironment.

Asunto(s)

Células Supresoras de Origen Mieloide , Neoplasias , Animales , Ratones , Células Madre Hematopoyéticas , Diferenciación Celular , Microambiente Tumoral

RESUMEN

Pathologically activated neutrophils (PMN) with immunosuppressive activity, which are termed myeloid-derived suppressor cells (PMN-MDSC), play a critical role in regulating tumor progression. These cells have been implicated in promoting tumor metastases by contributing to premetastatic niche formation. This effect was facilitated by enhanced spontaneous migration of PMN from bone marrow to the premetastatic niches during the early-stage of cancer development. The molecular mechanisms underpinning this phenomenon remained unclear. In this study, we found that syntaphilin (SNPH), a cytoskeletal protein previously known for anchoring mitochondria to the microtubule in neurons and tumor cells, could regulate migration of PMN. Expression of SNPH was decreased in PMN from tumor-bearing mice and patients with cancer as compared with PMN from tumor-free mice and healthy donors, respectively. In Snph-knockout (SNPH-KO) mice, spontaneous migration of PMN was increased and the mice showed increased metastasis. Mechanistically, in SNPH-KO mice, the speed and distance travelled by mitochondria in PMN was increased, rates of oxidative phosphorylation and glycolysis were elevated, and generation of adenosine was increased. Thus, our study reveals a molecular mechanism regulating increased migratory activity of PMN during cancer progression and suggests a novel therapeutic targeting opportunity.

Asunto(s)

Proteínas de la Membrana , Células Supresoras de Origen Mieloide , Neoplasias , Proteínas del Tejido Nervioso , Animales , Ratones , Movimiento Celular , Proteínas de la Membrana/metabolismo , Células Supresoras de Origen Mieloide/metabolismo , Neoplasias/patología , Neutrófilos/metabolismo

RESUMEN

Transitory appearance of immune suppressive polymorphonuclear neutrophils (PMNs) defined as myeloid-derived suppressor cells (PMNs-MDSCs) in newborns is important for their protection from inflammation associated with newly established gut microbiota. Here, we report that inhibition of the type I IFN (IFN1) pathway played a major role in regulation of PMNs-MDSCs-suppressive activity during first weeks of life. Expression of the IFN1 receptor IFNAR1 was markedly lower in PMNs-MDSCs. However, in newborn mice, down-regulation of IFNAR1 was not sufficient to render PMNs immune suppressive. That also required the presence of a positive signal from lactoferrin via its receptor low-density lipoprotein receptor-related protein 2. The latter effect was mediated via NF-κB activation, which was tempered by IFN1 in a manner that involved suppressor of cytokine signaling 3. Thus, we discovered a mechanism of tight regulation of immune suppressive PMNs-MDSCs in newborns, which may be used in the development of therapies of neonatal pathologies.

Asunto(s)

Células Supresoras de Origen Mieloide , Ratones , Animales , Neutrófilos , Lactoferrina/metabolismo , FN-kappa B/metabolismo , Citocinas/metabolismo , Lipoproteínas LDL/metabolismo

RESUMEN

Myeloid-derived suppressor cells (MDSC) are pathologically activated neutrophils and monocytes with potent immune suppressive activity. These cells play an important role in accelerating tumor progression and undermining the efficacy of anti-cancer therapies. The natural mechanisms limiting MDSC activity are not well understood. Here, we present evidence that type I interferons (IFN1) receptor signaling serves as a universal mechanism that restricts acquisition of suppressive activity by these cells. Downregulation of the IFNAR1 chain of this receptor is found in MDSC from cancer patients and mouse tumor models. The decrease in IFNAR1 depends on the activation of the p38 protein kinase and is required for activation of the immune suppressive phenotype. Whereas deletion of IFNAR1 is not sufficient to convert neutrophils and monocytes to MDSC, genetic stabilization of IFNAR1 in tumor bearing mice undermines suppressive activity of MDSC and has potent antitumor effect. Stabilizing IFNAR1 using inhibitor of p38 combined with the interferon induction therapy elicits a robust anti-tumor effect. Thus, negative regulatory mechanisms of MDSC function can be exploited therapeutically.

Asunto(s)

Interferón Tipo I/metabolismo , Células Supresoras de Origen Mieloide/inmunología , Neoplasias/metabolismo , Receptor de Interferón alfa y beta/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Animales , Antineoplásicos/farmacología , Médula Ósea , Línea Celular Tumoral , Modelos Animales de Enfermedad , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Persona de Mediana Edad , Monocitos/inmunología , Neutrófilos/inmunología , Receptor de Interferón alfa y beta/genética , Proteínas Quinasas p38 Activadas por Mitógenos/efectos de los fármacos , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo

RESUMEN

RESUMEN Con el objetivo de medir la frecuencia de las infecciones nosocomiales en las unidades de observación de medicina interna de los servicios de emergencia en dos hospitales de nivel III de Lima, se realizó un estudio de prevalencia de periodo durante cinco días en pacientes admitidos después de las 72 horas de observación y con descarte de infección comunitaria, utilizando datos obtenidos de las historias clínicas. Adicionalmente, se evaluó el hacinamiento y la ventilación de las salas de hospitalización. La frecuencia de las infecciones nosocomiales en los servicios de emergencia fue 8,1%, cuatro veces lo reportado como prevalencia de periodo en el Perú. Los factores de riesgo asociados fueron el tiempo prolongado de estancia y la carencia de ventilación apropiada del ambiente hospitalario. La ventilación inapropiada triplica el riesgo de aparición de infecciones nosocomiales.

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ABSTRACT The aim of this study was to measure the frequency of nosocomial infections in the internal medicine observation units of the emergency services in two level III hospitals in Lima. A 5-day prevalence study was carried out on patients admitted after a 72 hours observation period, in whom community-based infections were ruled out. Data was obtained from clinical records. Additionally, overcrowding and ventilation in the hospitalization rooms were evaluated. The frequency of nosocomial infections in the emergency services was found to be 8.1%, four times what was reported as period prevalence in Peru. The associated risk factors were prolonged length of stay and lack of proper ventilation in the hospital environment. Inadequate ventilation triples the risk of nosocomial infections.

Asunto(s)

Ventilación , Infección Hospitalaria , Eliminación de Residuos Sanitarios , Neumonía Asociada a la Atención Médica , Perú , Desinfección de las Manos , Registros Médicos , Unidades de Observación Clínica

RESUMEN

The aim of this study was to measure the frequency of nosocomial infections in the internal medicine observation units of the emergency services in two level III hospitals in Lima. A 5-day prevalence study was carried out on patients admitted after a 72 hours observation period, in whom community-based infections were ruled out. Data was obtained from clinical records. Additionally, overcrowding and ventilation in the hospitalization rooms were evaluated. The frequency of nosocomial infections in the emergency services was found to be 8.1%, four times what was reported as period prevalence in Peru. The associated risk factors were prolonged length of stay and lack of proper ventilation in the hospital environment. Inadequate ventilation triples the risk of nosocomial infections.

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Con el objetivo de medir la frecuencia de las infecciones nosocomiales en las unidades de observación de medicina interna de los servicios de emergencia en dos hospitales de nivel III de Lima, se realizó un estudio de prevalencia de periodo durante cinco días en pacientes admitidos después de las 72 horas de observación y con descarte de infección comunitaria, utilizando datos obtenidos de las historias clínicas. Adicionalmente, se evaluó el hacinamiento y la ventilación de las salas de hospitalización. La frecuencia de las infecciones nosocomiales en los servicios de emergencia fue 8,1%, cuatro veces lo reportado como prevalencia de periodo en el Perú. Los factores de riesgo asociados fueron el tiempo prolongado de estancia y la carencia de ventilación apropiada del ambiente hospitalario. La ventilación inapropiada triplica el riesgo de aparición de infecciones nosocomiales.

Asunto(s)

Unidades de Observación Clínica , Infección Hospitalaria , Servicio de Urgencia en Hospital , Infección Hospitalaria/epidemiología , Aglomeración , Humanos , Perú/epidemiología , Factores de Riesgo , Ventilación

RESUMEN

Primary tumor-derived factors (TDFs) act upon normal cells to generate a pre-metastatic niche, which promotes colonization of target organs by disseminated malignant cells. Here we report that TDFs-induced activation of the p38α kinase in lung fibroblasts plays a critical role in the formation of a pre-metastatic niche in the lungs and subsequent pulmonary metastases. Activation of p38α led to inactivation of type I interferon signaling and stimulation of expression of fibroblast activation protein (FAP). FAP played a key role in remodeling of the extracellular matrix as well as inducing the expression of chemokines that enable lung infiltration by neutrophils. Increased activity of p38 in normal cells was associated with metastatic disease and poor prognosis in human melanoma patients whereas inactivation of p38 suppressed lung metastases. We discuss the p38α-driven mechanisms stimulating the metastatic processes and potential use of p38 inhibitors in adjuvant therapy of metastatic cancers.

Asunto(s)

Neoplasias Pulmonares , Transducción de Señal , Fibroblastos/patología , Humanos , Pulmón/patología , Neoplasias Pulmonares/patología , Proteínas Quinasas

RESUMEN

Triple-negative breast cancer (TNBC) is particularly aggressive, with enhanced incidence of tumor relapse, resistance to chemotherapy, and metastases. As the mechanistic basis for this aggressive phenotype is unclear, treatment options are limited. Here, we showed an increased population of myeloid-derived immunosuppressor cells (MDSCs) in TNBC patients compared with non-TNBC patients. We found that high levels of the transcription factor ΔNp63 correlate with an increased number of MDSCs in basal TNBC patients, and that ΔNp63 promotes tumor growth, progression, and metastasis in human and mouse TNBC cells. Furthermore, we showed that MDSC recruitment to the primary tumor and metastatic sites occurs via direct ΔNp63-dependent activation of the chemokines CXCL2 and CCL22. CXCR2/CCR4 inhibitors reduced MDSC recruitment, angiogenesis, and metastasis, highlighting a novel treatment option for this subset of TNBC patients. Finally, we found that MDSCs secrete prometastatic factors such as MMP9 and chitinase 3-like 1 to promote TNBC cancer stem cell function, thereby identifying a nonimmunologic role for MDSCs in promoting TNBC progression. These findings identify a unique crosstalk between ΔNp63+ TNBC cells and MDSCs that promotes tumor progression and metastasis, which could be exploited in future combined immunotherapy/chemotherapy strategies for TNBC patients.

Asunto(s)

Células Supresoras de Origen Mieloide/inmunología , Células Madre Neoplásicas/inmunología , Factores de Transcripción/inmunología , Neoplasias de la Mama Triple Negativas/inmunología , Proteínas Supresoras de Tumor/inmunología , Animales , Quimiocina CCL22/genética , Quimiocina CCL22/inmunología , Quimiocina CXCL2/genética , Quimiocina CXCL2/inmunología , Proteína 1 Similar a Quitinasa-3/genética , Proteína 1 Similar a Quitinasa-3/inmunología , Femenino , Humanos , Células MCF-7 , Metaloproteinasa 9 de la Matriz/genética , Metaloproteinasa 9 de la Matriz/inmunología , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Células Supresoras de Origen Mieloide/patología , Metástasis de la Neoplasia , Células Madre Neoplásicas/patología , Receptores CCR4/genética , Receptores CCR4/inmunología , Receptores CXCR4/genética , Receptores CXCR4/inmunología , Factores de Transcripción/genética , Neoplasias de la Mama Triple Negativas/genética , Neoplasias de la Mama Triple Negativas/patología , Neoplasias de la Mama Triple Negativas/terapia , Proteínas Supresoras de Tumor/genética

RESUMEN

Although neutrophils have been linked to the formation of the pre-metastatic niche, the mechanism of their migration to distant, uninvolved tissues has remained elusive. We report that bone marrow neutrophils from mice with early-stage cancer exhibited much more spontaneous migration than that of control neutrophils from tumor-free mice. These cells lacked immunosuppressive activity but had elevated rates of oxidative phosphorylation and glycolysis, and increased production of ATP, relative to that of control neutrophils. Their enhanced spontaneous migration was mediated by autocrine ATP signaling through purinergic receptors. In ectopic tumor models and late stages of cancer, bone marrow neutrophils demonstrated potent immunosuppressive activity. However, these cells had metabolic and migratory activity indistinguishable from that of control neutrophils. A similar pattern of migration was observed for neutrophils and polymorphonuclear myeloid-derived suppressor cells from patients with cancer. These results elucidate the dynamic changes that neutrophils undergo in cancer and demonstrate the mechanism of neutrophils' contribution to early tumor dissemination.

Asunto(s)

Quimiotaxis de Leucocito/inmunología , Neoplasias/inmunología , Neoplasias/patología , Infiltración Neutrófila/inmunología , Neutrófilos/inmunología , Anciano , Animales , Progresión de la Enfermedad , Femenino , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Persona de Mediana Edad

RESUMEN

Cross-presentation is a critical function of dendritic cells (DCs) required for induction of antitumor immune responses and success of cancer immunotherapy. It is established that tumor-associated DCs are defective in their ability to cross-present antigens. However, the mechanisms driving these defects are still unknown. We find that impaired cross-presentation in DCs is largely associated with defect in trafficking of peptide-MHC class I (pMHC) complexes to the cell surface. DCs in tumor-bearing hosts accumulate lipid bodies (LB) containing electrophilic oxidatively truncated (ox-tr) lipids. These ox-tr-LB, but not LB present in control DCs, covalently bind to chaperone heat shock protein 70. This interaction prevents the translocation of pMHC to cell surface by causing the accumulation of pMHC inside late endosomes/lysosomes. As a result, tumor-associated DCs are no longer able to stimulate adequate CD8 T cells responses. In conclusion, this study demonstrates a mechanism regulating cross-presentation in cancer and suggests potential therapeutic avenues.

Asunto(s)

Antígenos/inmunología , Reactividad Cruzada/inmunología , Células Dendríticas/inmunología , Gotas Lipídicas/inmunología , Lípidos/inmunología , Neoplasias/inmunología , Animales , Presentación de Antígeno/inmunología , Línea Celular Tumoral , Células Dendríticas/metabolismo , Endosomas/inmunología , Endosomas/metabolismo , Femenino , Proteínas HSP70 de Choque Térmico/inmunología , Proteínas HSP70 de Choque Térmico/metabolismo , Antígenos de Histocompatibilidad Clase I/inmunología , Antígenos de Histocompatibilidad Clase I/metabolismo , Gotas Lipídicas/metabolismo , Lisosomas/inmunología , Lisosomas/metabolismo , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Transgénicos , Neoplasias/metabolismo , Neoplasias/patología , Unión Proteica

RESUMEN

Polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) are important regulators of immune responses in cancer and have been directly implicated in promotion of tumor progression. However, the heterogeneity of these cells and lack of distinct markers hampers the progress in understanding of the biology and clinical importance of these cells. Using partial enrichment of PMN-MDSC with gradient centrifugation we determined that low density PMN-MDSC and high density neutrophils from the same cancer patients had a distinct gene profile. Most prominent changes were observed in the expression of genes associated with endoplasmic reticulum (ER) stress. Surprisingly, low-density lipoprotein (LDL) was one of the most increased regulators and its receptor oxidized LDL receptor 1 OLR1 was one of the most overexpressed genes in PMN-MDSC. Lectin-type oxidized LDL receptor 1 (LOX-1) encoded by OLR1 was practically undetectable in neutrophils in peripheral blood of healthy donors, whereas 5-15% of total neutrophils in cancer patients and 15-50% of neutrophils in tumor tissues were LOX-1+. In contrast to their LOX-1- counterparts, LOX-1+ neutrophils had gene signature, potent immune suppressive activity, up-regulation of ER stress, and other biochemical characteristics of PMN-MDSC. Moreover, induction of ER stress in neutrophils from healthy donors up-regulated LOX-1 expression and converted these cells to suppressive PMN-MDSC. Thus, we identified a specific marker of human PMN-MDSC associated with ER stress and lipid metabolism, which provides new insight to the biology and potential therapeutic targeting of these cells.