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Cannabinoid-2 receptor depletion promotes non-alcoholic fatty liver disease in mice via disturbing gut microbiota and tryptophan metabolism
Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome. NAFLD encompasses a spectrum of liver damage starting with liver steatosis and lipid disorders presented as the hallmark. Cannabinoid-2 receptor (CB2R) is the receptor of endocannabinoids mainly expressed in immune cells. Our preliminary study revealed the preventative role of CB2R in liver injury related to lipid metabolism. In this study, we aimed to explore the role of CB2R in NAFLD and the underlying mechanism related to microbial community. High-fat diet-induced NAFLD model was established in mice. We found that hepatic CB2R expression was significantly reduced in NAFLD mice and CB2R–/– mice fed with normal chow. Interestingly, cohousing with or transplanted with microbiota from WT mice, or treatment with an antibiotic cocktail ameliorated the NAFLD phenotype of CB2R–/– mice. The gut dysbiosis in CB2R–/– mice including increased Actinobacteriota and decreased Bacteroidota was similar to that of NAFLD patients and NAFLD mice. Microbial functional analysis and metabolomics profiling revealed obviously disturbed tryptophan metabolism in NAFLD patients and NAFLD mice, which were also seen in CB2R–/– mice. Correlation network showed that the disordered tryptophan metabolites such as indolelactic acid (ILA) and xanthurenic acid in CB2R-/- mice were mediated by gut dysbiosis and related to NAFLD severity indicators. In vitro and in vivo validation experiments showed that the enriched tryptophan metabolites ILA aggravated NAFLD phenotypes. These results demonstrate the involvement of CB2R in NAFLD, which is related to gut microbiota-mediated tryptophan metabolites. Our findings highlight CB2R and the associated microbes and tryptophan metabolites as promising targets for the treatment of NAFLD.
Exploring metabolic reprogramming in esophageal cancer: the role of key enzymes in glucose, amino acid, and nucleotide pathways and targeted therapies
Esophageal cancer (EC) is one of the most common malignancies worldwide with the character of poor prognosis and high mortality. Despite significant advancements have been achieved in elucidating the molecular mechanisms of EC, for example, in the discovery of new biomarkers and metabolic pathways, effective treatment options for patients with advanced EC are still limited. Metabolic heterogeneity in EC is a critical factor contributing to poor clinical outcomes. This heterogeneity arises from the complex interplay between the tumor microenvironment and genetic factors of tumor cells, which drives significant metabolic alterations in EC, a process known as metabolic reprogramming. Understanding the mechanisms of metabolic reprogramming is essential for developing new antitumor therapies and improving treatment outcomes. Targeting the distinct metabolic alterations in EC could enable more precise and effective therapies. In this review, we explore the complex metabolic changes in glucose, amino acid, and nucleotide metabolism during the progression of EC, and how these changes drive unique nutritional demands in cancer cells. We also evaluate potential therapies targeting key metabolic enzymes and their clinical applicability. Our work will contribute to enhancing knowledge of metabolic reprogramming in EC and provide new insights and approaches for the clinical treatment of EC.
Type 2 immunity in allergic diseases
Significant advancements have been made in understanding the cellular and molecular mechanisms of type 2 immunity in allergic diseases such as asthma, allergic rhinitis, chronic rhinosinusitis, eosinophilic esophagitis (EoE), food and drug allergies, and atopic dermatitis (AD). Type 2 immunity has evolved to protect against parasitic diseases and toxins, plays a role in the expulsion of parasites and larvae from inner tissues to the lumen and outside the body, maintains microbe-rich skin and mucosal epithelial barriers and counterbalances the type 1 immune response and its destructive effects. During the development of a type 2 immune response, an innate immune response initiates starting from epithelial cells and innate lymphoid cells (ILCs), including dendritic cells and macrophages, and translates to adaptive T and B-cell immunity, particularly IgE antibody production. Eosinophils, mast cells and basophils have effects on effector functions. Cytokines from ILC2s and CD4+ helper type 2 (Th2) cells, CD8 + T cells, and NK-T cells, along with myeloid cells, including IL-4, IL-5, IL-9, and IL-13, initiate and sustain allergic inflammation via T cell cells, eosinophils, and ILC2s; promote IgE class switching; and open the epithelial barrier. Epithelial cell activation, alarmin release and barrier dysfunction are key in the development of not only allergic diseases but also many other systemic diseases. Recent biologics targeting the pathways and effector functions of IL4/IL13, IL-5, and IgE have shown promising results for almost all ages, although some patients with severe allergic diseases do not respond to these therapies, highlighting the unmet need for a more detailed and personalized approach.
PIK3CA mutation fortifies molecular determinants for immune signaling in vascular cancers
Angiosarcomas are a group of vascular cancers that form malignant blood vessels. These malignancies are seemingly inflamed primarily due to their pathognomonic nature, which consists of irregular endothelium and tortuous blood channels. PIK3CA mutations are oncogenic and disrupt the PI3K pathway. In this study, we aimed to define the molecular and functional consequences of oncogenic PIK3CA mutations in angiosarcoma. We first generated two isogenic hemangiosarcoma cell lines harboring the H1047R hotspot mutations in PIK3CA gene using CRISPR/Cas9. We found PIK3CA-mutant cells established distinct molecular signatures in global gene expression and chromatin accessibility, which were associated with enrichment of immune cytokine signaling, including IL-6, IL-8, and MCP-1. These molecular processes were disrupted by the PI3K-α specific inhibitor, alpelisib. We also observed that the molecular distinctions in PIK3CA-mutant cells were linked to metabolic reprogramming in glycolytic activity and mitochondrial respiration. Our multi-omics analysis revealed that activating PIK3CA mutations regulate molecular machinery that contributes to phenotypic alterations and resistance to alpelisib. Furthermore, we identified potential therapeutic vulnerabilities of PIK3CA mutations in response to PI3K-α inhibition mediated by MAPK signaling. In summary, we demonstrate that PIK3CA mutations perpetuate PI3K activation and reinforce immune enrichment to promote drug resistance in vascular cancers.
Targeting of TAMs: can we be more clever than cancer cells?
With increasing incidence and geography, cancer is one of the leading causes of death, reduced quality of life and disability worldwide. Principal progress in the development of new anticancer therapies, in improving the efficiency of immunotherapeutic tools, and in the personification of conventional therapies needs to consider cancer-specific and patient-specific programming of innate immunity. Intratumoral TAMs and their precursors, resident macrophages and monocytes, are principal regulators of tumor progression and therapy resistance. Our review summarizes the accumulated evidence for the subpopulations of TAMs and their increasing number of biomarkers, indicating their predictive value for the clinical parameters of carcinogenesis and therapy resistance, with a focus on solid cancers of non-infectious etiology. We present the state-of-the-art knowledge about the tumor-supporting functions of TAMs at all stages of tumor progression and highlight biomarkers, recently identified by single-cell and spatial analytical methods, that discriminate between tumor-promoting and tumor-inhibiting TAMs, where both subtypes express a combination of prototype M1 and M2 genes. Our review focuses on novel mechanisms involved in the crosstalk among epigenetic, signaling, transcriptional and metabolic pathways in TAMs. Particular attention has been given to the recently identified link between cancer cell metabolism and the epigenetic programming of TAMs by histone lactylation, which can be responsible for the unlimited protumoral programming of TAMs. Finally, we explain how TAMs interfere with currently used anticancer therapeutics and summarize the most advanced data from clinical trials, which we divide into four categories: inhibition of TAM survival and differentiation, inhibition of monocyte/TAM recruitment into tumors, functional reprogramming of TAMs, and genetic enhancement of macrophages.
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