RESUMO
The host's intestinal microbiota contributes to endocrine and metabolic responses, but a dysbiosis in this environment can lead to obesity and insulin resistance. Recent work has demonstrated a role for microbial metabolites in the regulation of gut hormones, including the metabolic hormone, glucagon-like peptide-1 (GLP-1). Muramyl dipeptide (MDP) is a bacterial cell wall component which has been shown to improve insulin sensitivity and glucose tolerance in diet-induced obese mice by acting through the nucleotide oligomerization domain 2 (NOD2) receptor. The purpose of this study was to understand the effects of MDP on GLP-1 secretion and glucose regulation. We hypothesized that MDP enhances glucose tolerance by inducing intestinal GLP-1 secretion through NOD2 activation. First, we observed a significant increase in GLP-1 secretion when murine and human L-cells were treated with a fatty acid MDP derivative (L18-MDP). Importantly, we demonstrated the expression of the NOD2 receptor in mouse intestine and in L-cells. In mice, two intraperitoneal injections of MDP (5 mg/kg body weight) caused a significant increase in fasting total GLP-1 in chow-fed mice, however this did not lead to an improvement in oral glucose tolerance. When mice were exposed to a high-fat diet, they eventually lost this MDP-induced GLP-1 release. Finally, we demonstrated in L-cells that hyperglycemic conditions reduce the mRNA expression of NOD2 and GLP-1. Together these findings suggest MDP may play a role in enhancing GLP-1 during normal glycemic conditions but loses its ability to do so in hyperglycemia.
Assuntos
Acetilmuramil-Alanil-Isoglutamina/farmacologia , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Hiperglicemia/metabolismo , Obesidade/metabolismo , Animais , Gorduras na Dieta/efeitos adversos , Gorduras na Dieta/farmacologia , Feminino , Humanos , Hiperglicemia/induzido quimicamente , Hiperglicemia/patologia , Masculino , Camundongos , Proteína Adaptadora de Sinalização NOD2/metabolismo , Obesidade/induzido quimicamente , Obesidade/patologiaRESUMO
Introduction: Epithelial ovarian cancer (OC) stands as one of the deadliest gynecologic malignancies, urgently necessitating novel therapeutic strategies. Approximately 60% of ovarian tumors exhibit reduced expression of major histocompatibility complex class I (MHC I), intensifying immune evasion mechanisms and rendering immunotherapies ineffective. NOD-like receptor CARD domain containing 5 (NLRC5) transcriptionally regulates MHC I genes and many antigen presentation machinery components. We therefore explored the therapeutic potential of NLRC5 in OC. Methods: We generated OC cells overexpressing NLRC5 to rescue MHC I expression and antigen presentation and then assessed their capability to respond to PD-L1 blockade and an infected cell vaccine. Results: Analysis of microarray datasets revealed a correlation between elevated NLRC5 expression and extended survival in OC patients; however, NLRC5 was scarcely detected in the OC tumor microenvironment. OC cells overexpressing NLRC5 exhibited slower tumor growth and resulted in higher recruitment of leukocytes in the TME with lower CD4/CD8 T-cell ratios and increased activation of T cells. Immune cells from peripheral blood, spleen, and ascites from these mice displayed heightened activation and interferon-gamma production when exposed to autologous tumor-associated antigens. Finally, as a proof of concept, NLRC5 overexpression within an infected cell vaccine platform enhanced responses and prolonged survival in comparison with control groups when challenged with parental tumors. Discussion: These findings provide a compelling rationale for utilizing NLRC5 overexpression in "cold" tumor models to enhance tumor susceptibility to T-cell recognition and elimination by boosting the presentation of endogenous tumor antigens. This approach holds promise for improving antitumoral immune responses in OC.
Assuntos
Neoplasias Ovarianas , Vacinas , Humanos , Feminino , Animais , Camundongos , Proteínas NLR , Domínio de Ativação e Recrutamento de Caspases , Microambiente Tumoral , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Antígenos de Histocompatibilidade Classe I , Neoplasias Ovarianas/genética , Antígenos de NeoplasiasRESUMO
Ovarian cancers exhibit high rates of recurrence and poor treatment response. Preclinical models that recapitulate human disease are critical to develop new therapeutic approaches. Syngeneic mouse models allow for the generation of tumours comprising the full repertoire of non-malignant cell types but have expanded in number, varying in the cell type of origin, method for transformation, and ultimately, the properties of the tumours they produce. Here we have performed a comparative analysis of high-grade serous ovarian cancer models based on transcriptomic profiling of 22 cell line models, and intrabursal and intraperitoneal tumours from 12. Among cell lines, we identify distinct signalling activity, such as elevated inflammatory signalling in STOSE and OVE16 models, and MAPK/ERK signalling in ID8 and OVE4 models; metabolic differences, such as reduced glycolysis-associated expression in several engineered ID8 subclones; and relevant functional properties, including differences in EMT activation, PD-L1 and MHC class I expression, and predicted chemosensitivity. Among tumour samples, we observe increased variability and stromal content among intrabursal tumours. Finally, we predict differences in the microenvironment of ID8 models engineered with clinically relevant mutations. We anticipate that this work will serve as a valuable resource, providing new insight to help select models for specific experimental objectives.
Assuntos
Neoplasias Ovarianas , Animais , Camundongos , Humanos , Feminino , Neoplasias Ovarianas/patologia , Perfilação da Expressão Gênica , Transdução de Sinais , Microambiente Tumoral/genéticaRESUMO
BACKGROUND: First Nations children in Canada experience health inequities. We aimed to determine whether a self-report health app identified children's needs for support earlier in their illness than would typically occur. METHODS: Children (aged 8 to 18 yr) were recruited from a rural First Nation community. Children completed the Aaniish Naa Gegii: the Children's Health and Well-being Measure (ACHWM) and then met with a local mental health worker who determined their risk status. ACHWM Emotional Quadrant Scores (EQS) were compared between 3 groups of children: healthy peers (HP) who were not at risk, those with newly identified needs (NIN) who were at risk and not previously identified, and a typical treatment (TT) group who were at risk and already receiving support. RESULTS: We included 227 children (57.1% girls), and the mean age was 12.9 (standard deviation [SD] 2.9) years. The 134 children in the HP group had a mean EQS of 80.1 (SD 11.25), the 35 children in the NIN group had a mean EQS of 67.2 (SD 13.27) and the 58 children in the TT group had a mean EQS of 66.2 (SD 16.30). The HP group had significantly better EQS than the NIN and TT groups (p < 0.001). The EQS did not differ between the NIN and TT groups (p = 0.8). INTERPRETATION: The ACHWM screening process identified needs for support among 35 children, and the associated triage process connected them to local services; the similarity of EQS in the NIN and TT groups highlights the value of community screening to optimize access to services. Future research will examine the impact of this process over the subsequent year in these groups.