Fatty acid-binding protein 5 limits the generation of Foxp3+ regulatory T cells through regulating plasmacytoid dendritic cell function in the tumor microenvironment

Metabolic Reprogramming in Tumor Immune Microenvironment: Impact on Immune Cell Function and Therapeutic Implications

Understanding of the metabolic reprogramming has revolutionized our insights into tumor progression and potential treatment. This review concentrates on the aberrant metabolic pathways in cancer cells within the tumor microenvironment (TME). Cancer cells differ from normal cells in their metabolic processing of glucose, amino acids, and lipids in order to adapt to heightened biosynthetic and energy needs. These metabolic shifts, which crucially alter lactic acid, amino acid and lipid metabolism, affect not only tumor cell proliferation but also TME dynamics. This review also explores the reprogramming of various immune cells in the TME. From a therapeutic standpoint, targeting these metabolic alterations represents a novel cancer treatment strategy. This review also discusses approaches targeting the regulation of metabolism of different nutrients in tumor cells and influencing the tumor microenvironment to enhance the immune response. In summary, this review summarizes metabolic reprogramming in cancer and its potential as a target for innovative therapeutic strategies, offering fresh perspectives on cancer treatment.

Single-cell sequencing analysis and multiple machine-learning models revealed the cellular crosstalk of dendritic cells and identified FABP5 and KLRB1 as novel biomarkers for psoriasis

Background

Psoriasis is an immune-mediated disorder influenced by environmental factors on a genetic basis. Despite advancements, challenges persist, including the diminishing efficacy of biologics and small-molecule targeted agents, alongside managing recurrence and psoriasis-related comorbidities. Unraveling the underlying pathogenesis and identifying valuable biomarkers remain pivotal for diagnosing and treating psoriasis.

Methods

We employed a series of bioinformatics (including single-cell sequencing data analysis and machine learning techniques) and statistical methods to integrate and analyze multi-level data. We observed the cellular changes in psoriatic skin tissues, screened the key genes Fatty acid binding protein 5 (FABP5) and The killer cell lectin-like receptor B1 (KLRB1), evaluated the efficacy of six widely prescribed drugs on psoriasis treatment in modulating the dendritic cell-associated pathway, and assessed their overall efficacy. Finally, RT-qPCR, immunohistochemistry, and immunofluorescence assays were used to validate.

Results

The regulatory influence of dendritic cells (DCs) on T cells through the CD70/CD27 signaling pathway may emerge as a significant facet of the inflammatory response in psoriasis. Notably, FABP5 and KLRB1 exhibited up-regulation and co-localization in psoriatic skin tissues and M5-induced HaCaT cells, serving as potential biomarkers influencing psoriasis development.

Conclusion

Our study analyzed the impact of DC-T cell crosstalk in psoriasis, elucidated the characterization of two biomarkers, FABP5 and KLRB1, in psoriasis, and highlighted the promise and value of tofacitinib in psoriasis therapy targeting DCs.

Fatty acid metabolism of immune cells: a new target of tumour immunotherapy

Metabolic competition between tumour cells and immune cells for limited nutrients is an important feature of the tumour microenvironment (TME) and is closely related to the outcome of tumour immune escape. A large number of studies have proven that tumour cells need metabolic reprogramming to cope with acidification and hypoxia in the TME while increasing energy uptake to support their survival. Among them, synthesis, oxidation and uptake of fatty acids (FAs) in the TME are important manifestations of lipid metabolic adaptation. Although different immune cell subsets often show different metabolic characteristics, various immune cell functions are closely related to fatty acids, including providing energy, providing synthetic materials and transmitting signals. In the face of the current situation of poor therapeutic effects of tumour immunotherapy, combined application of targeted immune cell fatty acid metabolism seems to have good therapeutic potential, which is blocked at immune checkpoints. Combined application of adoptive cell therapy and cancer vaccines is reflected. Therefore, it is of great interest to explore the role of fatty acid metabolism in immune cells to discover new strategies for tumour immunotherapy and improve anti-tumour immunity.

Curcumin analog GO-Y030 inhibits tumor metastasis and glycolysis

Tumor metastasis is one of the worst prognostic features of cancer. Although metastasis is a major cause of cancer-related deaths, an effective treatment has not yet been established. Here, we explore the antitumor effects of GO-Y030, a curcumin analog, via various mechanisms using a mouse model. GO-Y030 treatment of B16-F10 melanoma cells inhibited TGF-β expression and glycolysis. The invasion assay results showed almost complete invasion inhibition following GO-Y030 treatment. Mouse experiments demonstrated that GO-Y030 administration inhibited lung tumor metastasis without affecting vascular endothelial cells. Consistent with this result, GO-Y030 treatment led to the downregulation of MMP2 and VEGFα, inhibiting tumor invasion and metastasis. The silencing of eIF4B, a downstream molecule of S6, attenuated MMP2 expression. Our study demonstrates the novel efficacy of GO-Y030 in inhibiting tumor metastasis by regulating metastasis-associated gene expression via inhibiting dual access, glycolytic and TGF-β pathways.

Reprogramming the lipid metabolism of dendritic cells in tumor immunomodulation and immunotherapy

Dendritic cells (DCs) are the most potent antigen-presenting cells in the human body. They detect and process environmental signals and communicate with T cells to bridge innate and adaptive immunity. Cell activation, function, and survival are closely associated with cellular metabolism. An increasing number of studies have revealed that lipid metabolism affects DC activation as well as innate and acquired immune responses. Combining lipid metabolic regulation with immunotherapy can strengthen the ability of antigen-presentation and T-cell activation of DCs, improve the existing anti-tumor therapy, and overcome the defects of DC-related therapies in the current stage, which has great potential in cancer therapy. This review summarizes the lipid metabolism of DCs under physiological conditions, analyzes the role of reprogramming the lipid metabolism of DCs in tumor immune regulation, and discusses potential immunotherapeutic strategies.

Interleukin-10 increases macrophage-mediated chemotherapy resistance via FABP5 signaling in multiple myeloma

Macrophages (MΦs) protect multiple myeloma (MM) cells from chemotherapy-induced apoptosis, and interleukin-10 (IL-10) is frequently elevated in the MM microenvironment. However, the role of IL-10 in MΦ-induced tumor chemotherapy resistance has not yet been clarified. In the present study, bone marrow-derived MΦs were treated with IL-10 (IL10-MΦs), and IL10-MΦ-induced MM chemotherapy resistance was evaluated. IL-10 promoted MΦ-mediated resistance to MM chemotherapy. In addition, IL-10 treatment increased lipid accumulation and fatty acid β-oxidation in MΦs. Mechanistically, IL-10 increased fatty acid binding protein 5 (FABP5) expression in MΦs, and targeting FABP5 decreased MM chemotherapy resistance induced by IL10-MΦs in vitro and enhanced chemotherapeutic efficacy in vivo. Inhibition of FABP5 decreased the expression of Carnitine Palmitoyltransferase 1A (CPT1A) in IL10-MΦs. In addition, inhibition of CPT1A in IL10-MΦs decreased IL10-MΦ-mediated MM chemotherapy resistance. Peroxisome proliferator-activated receptor γ (PPARγ) is upstream of FABP5 signaling. Inhibition of PPARγ in IL10-MΦs decreased IL10-MΦ-mediated MM chemotherapy resistance in vitro. Collectively, our work indicates that IL-10 enhances MΦ-mediated MM chemotherapy resistance via FABP5 signaling and targeting FABP5 has potentially important clinical implications.

The emerging role of fatty acid binding protein 5 (FABP5) in cancers

Fatty acid binding protein 5 (FABP5, or epidermal FABP) is an intracellular chaperone of fatty acid molecules that regulates lipid metabolism and cell growth. In patient-derived tumours, FABP5 expression is increased up to tenfold, often co-expressed with other cancer-related proteins. High tumoral FABP5 expression is associated with poor prognosis. FABP5 activates transcription factors (TFs) leading to increased expression of proteins involved in tumorigenesis. Genetic and pharmacological preclinical studies show that inhibiting FABP5 reduces protumoral markers, whereas elevation of FABP5 promotes tumour growth and spread. Thus, FABP5 might be a valid target for novel therapeutics. The evidence base is currently strongest for liver, prostate, breast, and brain cancers, and squamous cell carcinoma (SCC), which could represent relevant patient populations for any drug discovery programme. Teaser: This review presents the growing evidence that upregulated fatty acid binding protein 5 (FABP5) plays a role in the progression of multiple cancer types, and may represent a novel therapeutic target.

Immunometabolic reprogramming, another cancer hallmark

Molecular carcinogenesis is a multistep process that involves acquired abnormalities in key biological processes. The complexity of cancer pathogenesis is best illustrated in the six hallmarks of the cancer: (1) the development of self-sufficient growth signals, (2) the emergence of clones that are resistant to apoptosis, (3) resistance to the antigrowth signals, (4) neo-angiogenesis, (5) the invasion of normal tissue or spread to the distant organs, and (6) limitless replicative potential. It also appears that non-resolving inflammation leads to the dysregulation of immune cell metabolism and subsequent cancer progression. The present article delineates immunometabolic reprogramming as a critical hallmark of cancer by linking chronic inflammation and immunosuppression to cancer growth and metastasis. We propose that targeting tumor immunometabolic reprogramming will lead to the design of novel immunotherapeutic approaches to cancer.

Comprehensive Analysis of the Roles of Fatty Acid Transport Related Proteins in Clear Cell Renal Cell Carcinoma

OBJECTIVE

This study aimed to explore the clinical significance of fatty acid transport-related protein (FATRP) in patients with clear cell renal cell carcinoma(ccRCC).

METHODS

RNA-seq data and corresponding clinical data of ccRCC were obtained from TCGA data portal. Seventeen key FATRP genes were comprehensively investigated using bioinformatics approaches to systematically investigate their expression patterns in ccRCC. In addition, the correlation between the expression levels of these genes and clinicopathological features in ccRCC was further explored.

RESULTS

Among the 17 key FATRP genes, only FABP5, FABP6, and FABP7 could be regarded as ideal biomarkers for ccRCC, as they were highly expressed in ccRCC tumor tissues, and positively correlates with tumor progression and poor prognosis. FABP6 had the highest copy number variations (CNV) events (63.07%), and ccRCC patients with FABP6 amplification had a better prognosis than the unaltered group. DNA methylation levels of FABP6 and FABP7 were downregulated in ccRCC tumor tissues compared to those in normal tissues. FABP5 showed the opposite results. Moreover, a novel four FATRP gene (FABP1, FABP5, FABP7, FATP2) and three clinical parameter (age, stage, and grade) prediction model was constructed and that comprised a significant independent prognostic signature.

CONCLUSIONS

Only a few FATRP genes are upregulated in ccRCC tumor tissue, and positively correlate with tumor progression and poor prognosis. The accuracy of a single gene of these FATRP genes as predictors of progression and prognosis of ccRCC is limited. The performance of the novel prediction model proposed by this study was much better than that of any single gene.

Mechanisms of nonalcoholic steatohepatitis-associated cardiomyopathy: key roles for liver-heart crosstalk

PURPOSE OF REVIEW

Nonalcoholic steatohepatitis (NASH) is a multisystem disease that affects not only the liver but also heart, pancreas, and kidney. We currently lack a comprehensive understanding of mechanisms responsible for the development of NASH-associated cardiomyopathy or the influence of sex on pathophysiology. There is a critical need to address these gaps in knowledge in order to accelerate translation of knowledge into clinical practice.

RECENT FINDINGS

NASH and cardiovascular disease share common risk factors such as chronic inflammation, hyperlipidemia, and insulin resistance. Early cardiac dysfunction in NASH that is independent of obesity or other cardiometabolic risk factors suggests roles for liver-heart crosstalk in disease pathogenesis. Inflammation is a driving force in the pathogenesis of NASH, and it is likely that 'spill over' of NASH inflammation contributes to the development of cardiomyopathy. However, molecular and cellular mechanisms that mediate NASH-associated cardiomyopathy remain unclear because of inherent limitations of experimental models. Even so, recent studies implicate inflammatory, metabolic, and physiologic mechanisms that enhance our understanding of NASH-associated cardiomyopathy and the role of liver-heart crosstalk.

SUMMARY

An innovative, detailed, and mechanistic understanding of NASH-associated cardiomyopathy is relevant to public health and will be fundamental for the comprehensive care of these patients.

Lipid metabolism in tumor microenvironment: novel therapeutic targets

Bioactive lipid molecules have been proposed to play important roles linking obesity/metabolic syndrome and cancers. Studies reveal that aberrant lipid metabolic signaling can reprogram cancer cells and non-cancer cells in the tumor microenvironment, contributing to cancer initiation, progression, metastasis, recurrence, and poor therapeutic response. Existing evidence indicates that controlling lipid metabolism can be a potential strategy for cancer prevention and therapy. By reviewing the current literature on the lipid metabolism in various cancers, we summarized major lipid molecules including fatty acids and cholesterol as well as lipid droplets and discussed their critical roles in cancer cells and non-cancer in terms of either promoting- or anti-tumorigenesis. This review provides an overview of the lipid molecules in cellular entities and their tumor microenvironment, adding to the existing knowledge with lipid metabolic reprogramming in immune cells and cancer associated cells. Comprehensive understanding of the regulatory role of lipid metabolism in cellular entities and their tumor microenvironment will provide a new direction for further studies, in a shift away from conventional cancer research. Exploring the lipid-related signaling targets that drive or block cancer development may lead to development of novel anti-cancer strategies distinct from traditional approaches for cancer prevention and treatment.

Intestinal fatty acid binding protein: A rising therapeutic target in lipid metabolism

Fatty acid binding proteins (FABPs) are key proteins in lipid transport, and the isoforms are segregated according to their tissue origins. Several isoforms, such as adipose-FABP and epidermal-FABP, have been shown to participate in multiple pathologic processes due to their ubiquitous expression. Intestinal fatty acid binding protein, also termed FABP2 or I-FABP, is specifically expressed in the small intestine. FABP2 can traffic lipids from the intestinal lumen to enterocytes and bind superfluous fatty acids to maintain a steady pool of fatty acids in the epithelium. As a lipid chaperone, FABP2 can also carry lipophilic drugs to facilitate targeted transport. When the integrity of the intestinal epithelium is disrupted, FABP2 is released into the circulation. Thus, it can potentially serve as a clinical biomarker. In this review, we discuss the pivotal role of FABP2 in intestinal lipid metabolism. We also summarize the molecular interactions that have been reported to date, highlighting the clinical prospects of FABP2 research.

Intracellular Lipid Accumulation Drives the Differentiation of Decidual Polymorphonuclear Myeloid-Derived Suppressor Cells via Arachidonic Acid Metabolism

Decidual polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) are essential to immune tolerance during pregnancy. A reduction in the number of these cells is associated with unexplained recurrent pregnancy loss (URPL). In our previous study, we reported that PMN-MDSCs are a group of mature neutrophils that are activated by the decidua microenvironment. In the present study, we show that the decidua microenvironment induces substantial lipid accumulation in neutrophils during their differentiation to PMN-MDSCs. Lower levels of lipid accumulation are detected in PMN-MDSCs from URPL patients, and the amount of lipid in the PMN-MDSCs is positively correlated with the proportion of PMN-MDSCs. Next, we demonstrate that decidua-derived IL6 with the presence of arachidonic acid upregulates fatty acid-binding protein 5 (FABP5) via the phosphorylation of signal transducer and activator of transcription 3 (STAT3). Fy -60ABP5 then continuously stimulates intracellular lipid accumulation. Increased intracellular lipid accumulation mediates arachidonic acid metabolism, a pathway that is significantly activated by the induction of the decidua microenvironment, to stimulate the synthesis of prostaglandin E2 (PGE2) and finally induce the differentiation of PMN-MDSCs. To summarize, decidua-derived IL6 facilitates the differentiation of PMN-MDSCs from neutrophils via the pSTAT3/FABP5/PGE2 pathway. Defects in the process may result in impaired differentiation and dysfunction of PMN-MDSCs in URPL. These findings enhance our understanding of the physiological mechanisms of immune tolerance in pregnancy and provide therapeutic options for URPL.