The Interplay Between Tissue Niche and Macrophage Cellular Metabolism in Obesity

A 30-color spectral flow cytometry panel for comprehensive analysis of immune cell composition and macrophage subsets in mouse metabolic organs

Obesity-induced chronic low-grade inflammation, also known as metaflammation, results from alterations of the immune response in metabolic organs and contributes to the development of fatty liver diseases and type 2 diabetes. The diversity of tissue-resident leukocytes involved in these metabolic dysfunctions warrants an in-depth immunophenotyping in order to elucidate disease etiology. Here, we present a 30-color, full spectrum flow cytometry panel, designed to (i) identify the major innate and adaptive immune cell subsets in murine liver and white adipose tissues and (ii) discriminate various tissue-specific myeloid subsets known to contribute to the development of metabolic dysfunctions. This panel notably allows for distinguishing embryonically-derived liver-resident Kupffer cells from newly recruited monocyte-derived macrophages and KCs. Furthermore, several adipose tissue macrophage (ATM) subsets, including perivascular macrophages, lipid-associated macrophages, and pro-inflammatory CD11c+ ATMs, can also be identified. Finally, the panel includes cell-surface markers that have been associated with metabolic activation of different macrophage and dendritic cell subsets. Altogether, our spectral flow cytometry panel allows for an extensive immunophenotyping of murine metabolic tissues, with a particular focus on metabolically-relevant myeloid cell subsets, and can easily be adjusted to include various new markers if needed.

Adipose tissue macrophage heterogeneity in the single-cell genomics era

It is now well-accepted that obesity-induced inflammation plays an important role in the development of insulin resistance and type 2 diabetes. A key source of the inflammation is the murine epididymal and human visceral adipose tissue. The current paradigm is that obesity activates multiple proinflammatory immune cell types in adipose tissue, including adipose-tissue macrophages (ATMs), T Helper 1 (Th1) T cells, and natural killer (NK) cells, while concomitantly suppressing anti-inflammatory immune cells such as T Helper 2 (Th2) T cells and regulatory T cells (Tregs). A key feature of the current paradigm is that obesity induces the anti-inflammatory M2 ATMs in lean adipose tissue to polarize into proinflammatory M1 ATMs. However, recent single-cell transcriptomics studies suggest that the story is much more complex. Here we describe the single-cell genomics technologies that have been developed recently and the emerging results from studies using these technologies. While further studies are needed, it is clear that ATMs are highly heterogeneous. Moreover, while a variety of ATM clusters with quite distinct features have been found to be expanded by obesity, none truly resemble classical M1 ATMs. It is likely that single-cell transcriptomics technology will further revolutionize the field, thereby promoting our understanding of ATMs, adipose-tissue inflammation, and insulin resistance and accelerating the development of therapies for type 2 diabetes.

Nutrient-sensing growth hormone secretagogue receptor in macrophage programming and meta-inflammation

OBJECTIVE

Obesity-associated chronic inflammation, aka meta-inflammation, is a key pathogenic driver for obesity-associated comorbidity. Growth hormone secretagogue receptor (GHSR) is known to mediate the effects of nutrient-sensing hormone ghrelin in food intake and fat deposition. We previously reported that global Ghsr ablation protects against diet-induced inflammation and insulin resistance, but the site(s) of action and mechanism are unknown. Macrophages are key drivers of meta-inflammation. To unravel the role of GHSR in macrophages, we generated myeloid-specific Ghsr knockout mice (LysM-Cre;Ghsrf/f).

METHODS

LysM-Cre;Ghsrf/f and control Ghsrf/f mice were subjected to 5 months of high-fat diet (HFD) feeding to induce obesity. In vivo, metabolic profiling of food intake, physical activity, and energy expenditure, as well as glucose and insulin tolerance tests (GTT and ITT) were performed. At termination, peritoneal macrophages (PMs), epididymal white adipose tissue (eWAT), and liver were analyzed by flow cytometry and histology. For ex vivo studies, bone marrow-derived macrophages (BMDMs) were generated from the mice and treated with palmitic acid (PA) or lipopolysaccharide (LPS). For in vitro studies, macrophage RAW264.7 cells with Ghsr overexpression or Insulin receptor substrate 2 (Irs2) knockdown were studied.

RESULTS

We found that Ghsr expression in PMs was increased under HFD feeding. In vivo, HFD-fed LysM-Cre;Ghsrf/f mice exhibited significantly attenuated systemic inflammation and insulin resistance without affecting food intake or body weight. Tissue analysis showed that HFD-fed LysM-Cre;Ghsrf/f mice have significantly decreased monocyte/macrophage infiltration, pro-inflammatory activation, and lipid accumulation, showing elevated lipid-associated macrophages (LAMs) in eWAT and liver. Ex vivo, Ghsr-deficient macrophages protected against PA- or LPS-induced pro-inflammatory polarization, showing reduced glycolysis, increased fatty acid oxidation, and decreased NF-κB nuclear translocation. At molecular level, GHSR metabolically programs macrophage polarization through PKA-CREB-IRS2-AKT2 signaling pathway.

CONCLUSIONS

These novel results demonstrate that macrophage GHSR plays a key role in the pathogenesis of meta-inflammation, and macrophage GHSR promotes macrophage infiltration and induces pro-inflammatory polarization. These exciting findings suggest that GHSR may serve as a novel immunotherapeutic target for the treatment of obesity and its associated comorbidity.

Vital role for primary healthcare providers: urgent need to educate the community about daily nutritional self-care to support immune function and maintain health

The importance of self-care to improve health and social well-being is well recognised. Nevertheless, there remains a need to encourage people to better understand how their body works, and how to keep it healthy. Because of its important role, part of this understanding should be based on why the immune system must be supported. This highly complex system is essential for defending against pathogens, but also for maintaining health throughout the body by preserving homeostasis and integrity. Accordingly, the immune system requires active management for optimal functioning and to reduce the risk of chronic diseases. In addition to regular exercise, healthy sleeping patterns, cultivating mental resilience, adequate nutrition through healthy and diverse dietary habits is key to the daily support of immune function. Diet and the immune system are closely intertwined, and a poor diet will impair immunity and increase the risk of acute and chronic diseases. To help elucidate the roles of primary healthcare providers in supporting individuals to engage in self-care, an international group of experts reviewed the evidence for the roles of the immune system in maintaining health and for nutrition in daily immune support, and discussed implications for population health and clinical practice.

Absence of Either Ripk3 or Mlkl Reduces Incidence of Hepatocellular Carcinoma Independent of Liver Fibrosis

Nonalcoholic fatty liver disease (NAFLD) is one of the etiologies that contribute to hepatocellular carcinoma (HCC), and chronic inflammation is one of the proposed mediators of HCC. Because necroptosis is a cell death pathway that induces inflammation, we tested whether necroptosis-induced inflammation contributes to the progression of NAFLD to HCC in a mouse model of diet-induced HCC. Male and female wild-type (WT) mice and mouse models where necroptosis is blocked (Ripk3-/- or Mlkl-/- mice) were fed either a control diet, choline-deficient low-fat diet or choline-deficient high-fat diet. Blocking necroptosis reduced markers of inflammation [proinflammatory cytokines (TNFα, IL6, and IL1β), F4/80+ve macrophages, CCR2+ve infiltrating monocytes], inflammation-associated oncogenic pathways (JNK, PD-L1/PD-1, β-catenin), and HCC in male mice. We demonstrate that hepatic necroptosis promotes recruitment and activation of liver macrophages leading to chronic inflammation, which in turn trigger oncogenic pathways leading to the progression of NAFLD to HCC in male mice. Whereas in female mice, blocking necroptosis reduced HCC independent of inflammation. Our data show a sex-specific difference in the development of inflammation, fibrosis, and HCC in WT mice. However, blocking necroptosis reduced HCC in both males and females without altering liver fibrosis. Thus, our study suggests that necroptosis is a valid therapeutic target for NAFLD-mediated HCC.

IMPLICATIONS

Necroptosis is a major contributor to hepatic inflammation that drives the progression of NAFLD to HCC and therefore represents a valid target for NAFLD-mediated HCC.

Adipokines in obesity and metabolic-related-diseases

The discovery of leptin in the 1990s led to a reconsideration of adipose tissue (AT) as not only a fatty acid storage organ, but also a proper endocrine tissue. AT is indeed capable of secreting bioactive molecules called adipokines for white AT or batokines for brown/beige AT, which allow communication with numerous organs, especially brain, heart, liver, pancreas, and/or the vascular system. Adipokines exert pro or anti-inflammatory activities. An equilibrated balance between these two sets ensures homeostasis of numerous tissues and organs. During the development of obesity, AT remodelling leads to an alteration of its endocrine activity, with increased secretion of pro-inflammatory adipokines relative to the anti-inflammatory ones, as shown in the graphical abstract. Pro-inflammatory adipokines take part in the initiation of local and systemic inflammation during obesity and contribute to comorbidities associated to obesity, as detailed in the present review.

Adipocyte- and Monocyte-Mediated Vicious Circle of Inflammation and Obesity (Review of Cellular and Molecular Mechanisms)

Monocytes play a key role in the development of metabolic syndrome, and especially obesity. Given the complex features of their development from progenitor cells, whose regulation is mediated by their interactions with bone marrow adipocytes, the importance of a detailed study of the heterogeneous composition of monocytes at the molecular and systemic levels becomes clear. Research argues for monocytes as indicators of changes in the body's metabolism and the possibility of developing therapeutic strategies to combat obesity and components of metabolic syndrome based on manipulations of the monocyte compound of the immune response. An in-depth study of the heterogeneity of bone-marrow-derived monocytes and adipocytes could provide answers to many questions about the pathogenesis of obesity and reveal their therapeutic potential.

Effects of Bacillus Calmette-Guérin on immunometabolism, microbiome and liver diseases⋆

Metabolic diseases have overtaken infectious diseases as the most serious public health issue and economic burden in most countries. Moreover, metabolic diseases increase the risk of having infectious diseases. The treatment of metabolic disease may require a long-term strategy of taking multiple medications, which can be costly and have side effects. Attempts to expand the therapeutic use of vaccination to prevent or treat metabolic diseases have attracted significant interest. A growing body of evidence indicates that Bacillus Calmette-Guérin (BCG) offers protection against non-infectious diseases. The non-specific effects of BCG occur likely due to the induction of trained immunity. In this regard, understanding how BCG influences the development of chronic metabolic health including liver diseases would be important. This review focuses on research on BCG, the constellation of disorders associated with metabolic health issues including liver diseases and diabetes as well as how BCG affects the gut microbiome, immunity, and metabolism.

Type 2 Diabetes Mellitus and Liver Disease: Across the Gut-Liver Axis from Fibrosis to Cancer

Type 2 diabetes mellitus is a widespread disease worldwide, and is one of the cornerstones of metabolic syndrome. The existence of a strong relationship between diabetes and the progression of liver fibrosis has been demonstrated by several studies, using invasive and noninvasive techniques. Patients with type 2 diabetes mellitus (T2DM) and nonalcoholic fatty liver disease (NAFLD) show faster progression of fibrosis than patients without diabetes. Many confounding factors make it difficult to determine the exact mechanisms involved. What we know so far is that both liver fibrosis and T2DM are expressions of metabolic dysfunction, and we recognize similar risk factors. Interestingly, both are promoted by metabolic endotoxemia, a low-grade inflammatory condition caused by increased endotoxin levels and linked to intestinal dysbiosis and increased intestinal permeability. There is broad evidence on the role of the gut microbiota in the progression of liver disease, through both metabolic and inflammatory mechanisms. Therefore, dysbiosis that is associated with diabetes can act as a modifier of the natural evolution of NAFLD. In addition to diet, hypoglycemic drugs play an important role in this scenario, and their benefit is also the result of effects exerted in the gut. Here, we provide an overview of the mechanisms that explain why diabetic patients show a more rapid progression of liver disease up to hepatocellular carcinoma (HCC), focusing especially on those involving the gut-liver axis.

Macrophages in immunoregulation and therapeutics

Macrophages exist in various tissues, several body cavities, and around mucosal surfaces and are a vital part of the innate immune system for host defense against many pathogens and cancers. Macrophages possess binary M1/M2 macrophage polarization settings, which perform a central role in an array of immune tasks via intrinsic signal cascades and, therefore, must be precisely regulated. Many crucial questions about macrophage signaling and immune modulation are yet to be uncovered. In addition, the clinical importance of tumor-associated macrophages is becoming more widely recognized as significant progress has been made in understanding their biology. Moreover, they are an integral part of the tumor microenvironment, playing a part in the regulation of a wide variety of processes including angiogenesis, extracellular matrix transformation, cancer cell proliferation, metastasis, immunosuppression, and resistance to chemotherapeutic and checkpoint blockade immunotherapies. Herein, we discuss immune regulation in macrophage polarization and signaling, mechanical stresses and modulation, metabolic signaling pathways, mitochondrial and transcriptional, and epigenetic regulation. Furthermore, we have broadly extended the understanding of macrophages in extracellular traps and the essential roles of autophagy and aging in regulating macrophage functions. Moreover, we discussed recent advances in macrophages-mediated immune regulation of autoimmune diseases and tumorigenesis. Lastly, we discussed targeted macrophage therapy to portray prospective targets for therapeutic strategies in health and diseases.

Mitochondrial Dysfunction: At the Nexus between Alcohol-Associated Immunometabolic Dysregulation and Tissue Injury

Alcohol misuse, directly or indirectly as a result of its metabolism, negatively impacts most tissues, including four with critical roles in energy metabolism regulation: the liver, pancreas, adipose, and skeletal muscle. Mitochondria have long been studied for their biosynthetic roles, such as ATP synthesis and initiation of apoptosis. However, current research has provided evidence that mitochondria participate in myriad cellular processes, including immune activation, nutrient sensing in pancreatic β-cells, and skeletal muscle stem and progenitor cell differentiation. The literature indicates that alcohol impairs mitochondrial respiratory capacity, promoting reactive oxygen species (ROS) generation and disrupting mitochondrial dynamics, leading to dysfunctional mitochondria accumulation. As discussed in this review, mitochondrial dyshomeostasis emerges at a nexus between alcohol-disrupted cellular energy metabolism and tissue injury. Here, we highlight this link and focus on alcohol-mediated disruption of immunometabolism, which refers to two distinct, yet interrelated processes. Extrinsic immunometabolism involves processes whereby immune cells and their products influence cellular and/or tissue metabolism. Intrinsic immunometabolism describes immune cell fuel utilization and bioenergetics that affect intracellular processes. Alcohol-induced mitochondrial dysregulation negatively impacts immunometabolism in immune cells, contributing to tissue injury. This review will present the current state of literature, describing alcohol-mediated metabolic and immunometabolic dysregulation from a mitochondrial perspective.

Garlic-derived exosomes regulate PFKFB3 expression to relieve liver dysfunction in high-fat diet-fed mice via macrophage-hepatocyte crosstalk

BACKGROUND

Although macrophage-mediated low-grade chronic inflammation and liver dysfunction have been found to be associated with the development of non-alcoholic fatty (NAFLD) and widely reported, but strategies and drugs targeting macrophages for the treatment of NAFLD are limited.

HYPOTHESIS/PURPOSE

Garlic-derived exosomes (GDE) can be useful for NAFLD due to its anti-inflammatory activity. Clarify whether GDE improves liver dysfunction through macrophage-hepatocyte crosstalk.

METHODS

GDE was isolated with PEG precipitation and ultracentrifuge. Inflammatory cytokines were detected by qRT-PCR and ELISA. Expression of 6-phosphofructo-2-kinase/fructose-2, 6-biphosphatase 3 (PFKFB3) was determined using qRT-PCR and western blot. Crosstalk between macrophages and hepatocytes was identified through a co-culture experiment. Small RNA sequencing and bioinformatic analysis were used to identify the key element of GDE regulating the expression of PFKFB3 gene.

RESULTS

GDE regulated the expression of PFKFB3 to reduce the inflammatory response in LPS-treated differentiated THP-1 macrophages. Data from small RNA sequencing and bioinformatics analysis reveal that miR-396e, one of the most abundant miRNAs of GDE, is the key component to regulate PFKFB3 expression. Mechanistically, miR-396e-mediating PFKFB3 expression plays a crucial role in GDE inhibiting inflammatory response and enhancing lipid metabolism in hepatocytes via the macrophage-hepatocyte crosstalk. Notably, GDE supplementation reduced the inflammatory response and improved liver dysfunction in high-fat diet-fed mice.

CONCLUSION

GDE may be useful for improving the symptoms of NAFLD via macrophage-hepatocyte crosstalk and its role in PFKFB3 expression.

Myeloid p38 activation maintains macrophage-liver crosstalk and BAT thermogenesis through IL-12-FGF21 axis

Obesity features excessive fat accumulation in several body tissues and induces a state of chronic low-grade inflammation that contributes to the development of diabetes, steatosis, and insulin resistance. Recent research has shown that this chronic inflammation is crucially dependent on p38 pathway activity in macrophages, suggesting p38 inhibition as a possible treatment for obesity comorbidities. Nevertheless, we report here that lack of p38 activation in myeloid cells worsens high-fat diet-induced obesity, diabetes, and steatosis. Deficient p38 activation increases macrophage IL-12 production, leading to inhibition of hepatic FGF21 and reduction of thermogenesis in the brown fat. The implication of FGF21 in the phenotype was confirmed by its specific deletion in hepatocytes. We also found that IL-12 correlates with liver damage in human biopsies, indicating the translational potential of our results. Our findings suggest that myeloid p38 has a dual role in inflammation and that drugs targeting IL-12 might improve the homeostatic regulation of energy balance in response to metabolic stress.

Is obesity-induced ECM remodeling a prelude to the development of various diseases?

Due to the increasing incidence rate of obesity worldwide and the associated complications such as type 2 diabetes and cardiovascular diseases, research on the adipose tissue physiology and the role of the extracellular matrix (ECM) has gained tremendous attention. The ECM, one of the most crucial components in body tissues, undergoes remodeling and regeneration of its constituents to guarantee normal tissue function. There is a crosstalk between fat tissue and various body organs, including but not limited to the liver, heart, kidney, skeletal muscle, and so forth. These organs respond to fat tissue signals through changes in ECM, function, and their secretory products. Obesity can cause ECM remodeling, inflammation, fibrosis, insulin resistance, and disrupted metabolism in different organs. However, the mechanisms underlying the reciprocal communication between various organs during obesity are still not fully elucidated. Gaining a profound knowledge of ECM alterations during the progression of obesity will pave the way toward developing potential strategies to either circumvent pathological conditions or open an avenue to treat complications associated with obesity.

Maternal obesity and programming of metabolic syndrome in the offspring: searching for mechanisms in the adipocyte progenitor pool

BACKGROUND

It is now understood that it is the quality rather than the absolute amount of adipose tissue that confers risk for obesity-associated disease. Adipose-derived stem cells give rise to adipocytes during the developmental establishment of adipose depots. In adult depots, a reservoir of progenitors serves to replace adipocytes that have reached their lifespan and for recruitment to increase lipid buffering capacity under conditions of positive energy balance. MAIN: The adipose tissue expandability hypothesis posits that a failure in de novo differentiation of adipocytes limits lipid storage capacity and leads to spillover of lipids into the circulation, precipitating the onset of obesity-associated disease. Since adipose progenitors are specified to their fate during late fetal life, perturbations in the intrauterine environment may influence the rapid expansion of adipose depots that occurs in childhood or progenitor function in established adult depots. Neonates born to mothers with obesity or diabetes during pregnancy tend to have excessive adiposity at birth and are at increased risk for childhood adiposity and cardiometabolic disease.

CONCLUSION

In this narrative review, we synthesize current knowledge in the fields of obesity and developmental biology together with literature from the field of the developmental origins of health and disease (DOHaD) to put forth the hypothesis that the intrauterine milieu of pregnancies complicated by maternal metabolic disease disturbs adipogenesis in the fetus, thereby accelerating the trajectory of adipose expansion in early postnatal life and predisposing to impaired adipose plasticity.

Amelioration of obesity-induced white adipose tissue inflammation by Bacillus coagulans T4 in a high-fat diet-induced obese murine model

AIM

Fresh evidence suggests that B. coagulans can be regarded as a promising therapeutic alternative for metabolic disorders. However, the possible effects of this probiotic on obesity-induced adipose tissue inflammation are unknown.

METHODS

C57BL/6j male mice were assigned to a normal-chow diet (NCD) or a high-fat diet (HFD) for 10 weeks. After this period, HFD-fed mice were randomly divided into two groups; HFD control group and HFD plus B. coagulans T4 (IBRC-N10791) for another 8 weeks. B. coagulans T4 was administrated daily by oral intragastric gavage (1 × 10⁹ colony-forming units).

KEY FINDINGS

Here, we found that B. coagulans successfully mitigated obesity and related metabolic disorder, as indicated by reduced body weight gain, decreased adiposity, and improved glucose tolerance. B. coagulans T4 administration also inhibited HFD-induced macrophage accumulation in white adipose tissue and switched M1 to M2 macrophages. In parallel, B. coagulans T4 treatment attenuated HFD-induced alteration in mRNA expression of pro/anti-inflammatory cytokines and Tlr4 in white adipose tissue. Moreover, B. coagulans T4 supplementation reduced the Firmicutes/Bacteriodetes ratio and increased the number of Lactobacillus and Faecalibacterium compared to the HFD group. Additionally, a significant increase in propionate and acetate levels in the HFD group was seen following B. coagulans T4 administration.

SIGNIFICANCE

Taken together, the present study provides evidence that B. coagulans T4 supplementation exerts anti-obesity effects in part through attenuating inflammation in adipose tissue. The present study will have significant implications for obesity management.

Dysfunction of macrophages leads to diabetic bone regeneration deficiency

Insufficient bone matrix formation caused by diabetic chronic inflammation can result in bone nonunion, which is perceived as a worldwide epidemic, with a substantial socioeconomic and public health burden. Macrophages in microenvironment orchestrate the inflammation and launch the process of bone remodeling and repair, but aberrant activation of macrophages can drive drastic inflammatory responses during diabetic bone regeneration. In diabetes mellitus, the proliferation of resident macrophages in bone microenvironment is limited, while enhanced myeloid differentiation of hematopoietic stem cells (HSCs) leads to increased and constant monocyte recruitment and thus macrophages shift toward the classic pro-inflammatory phenotype, which leads to the deficiency of bone regeneration. In this review, we systematically summarized the anomalous origin of macrophages under diabetic conditions. Moreover, we evaluated the deficit of pro-regeneration macrophages in the diabetic inflammatory microenvironment. Finally, we further discussed the latest developments on strategies based on targeting macrophages to promote diabetic bone regeneration. Briefly, this review aimed to provide a basis for modulating the biological functions of macrophages to accelerate bone regeneration and rescue diabetic fracture healing in the future.

Adipose tissue macrophage in obesity-associated metabolic diseases

Adipose tissue macrophage (ATM) has been appreciated for its critical contribution to obesity-associated metabolic diseases in recent years. Here, we discuss the regulation of ATM on both metabolic homeostatsis and dysfunction. In particular, the macrophage polarization and recruitment as well as the crosstalk between ATM and adipocyte in thermogenesis, obesity, insulin resistance and adipose tissue fibrosis have been reviewed. A better understanding of how ATM regulates adipose tissue remodeling may provide novel therapeutic strategies against obesity and associated metabolic diseases.

Investigating the multi-target therapeutic mechanism of Guihuang formula on Chronic Prostatitis

ETHNOPHARMACOLOGICAL RELEVANCE

Chronic prostatitis (CP) is a complex, intractable and prevalent urological disorder in men with no effective treatment. Guihuang formula (GHF) is a traditional Chinese medicine compound that is advantageous as a CP treatment, but its aetiology is poorly understood. Research and exploration of the mechanism of GHF will help the development of a potentially valuable drug for CP and provide deeper insight into CP.

AIM OF THE STUDY

To examine and further clarify the multi-target therapeutic mechanism of GHF on CP.

MATERIALS AND METHODS

The chemical components in GHF were identified using UPLC-Q/TOF-MS. The active components and potential targets of GHF for the treatment of CP were screened and analyzed using network pharmacology and molecular docking. We constructed a CP rat model to investigate the therapeutic effect of GHF on CP and verify the influence of key targets and core pathways based on the results of network pharmacology.

RESULTS

A total of 143 ingredients were identified in GHF using UPLC-Q/TOF-MS, and 111 potential targets for GHF of CP were predicted. The "drug-ingredient-target-pathway" network was constructed and in compliance with the "Jun-Chen-Zuo-Shi" principle. GHF significantly reduced the prostate index, alleviated histological damage in the prostate, decreased CD3⁺ T cells and CD45⁺ leukocyte infiltration in the prostate, downregulated the expression of the proinflammatory cytokines IL-1β, IL-6, IL-18, COX-2, MCP-1 and TNF-α, decreased ROS levels and alleviated the production of MDA accompanied by an increase of SOD and GSH-PX levels. Meanwhile, GHF suppressed apoptosis in macrophages, downregulated the mRNA levels of PI3K, AKT and P65 NF-κB and inhibited the phosphorylation of the PI3K, AKT and P65 NF-κB.

CONCLUSION

A network pharmacology and experimental validation-based strategy was used to elucidate the underlying "multicomponent, multitarget, and multipathway" mode of action of GHF against CP. We verified that GHF inhibited oxidative stress and inflammatory response, suppressed apoptosis in macrophages, inhibited the activation of the inflammation-related PI3K/AKT/NF-κB pathway in CP rat. These findings extend the conventional views of "one drug hits one target", and offer novel insights and indication paradigm for the future discovery on the multi-target therapeutic mechanism of traditional Chinese medicine compound.

FOXO3 Expression in Macrophages Is Lowered by a High-Fat Diet and Regulates Colonic Inflammation and Tumorigenesis

Obesity, characterized by augmented inflammation and tumorigenesis, is linked to genetic predispositions, such as FOXO3 polymorphisms. As obesity is associated with aberrant macrophages infiltrating different tissues, including the colon, we aimed to identify FOXO3-dependent transcriptomic changes in macrophages that drive obesity-mediated colonic inflammation and tumorigenesis. We found that in mouse colon, high-fat-diet-(HFD)-related obesity led to diminished FOXO3 levels and increased macrophages. Transcriptomic analysis of mouse peritoneal FOXO3-deficient macrophages showed significant differentially expressed genes (DEGs; FDR < 0.05) similar to HFD obese colons. These DEG-related pathways, linked to mouse colonic inflammation and tumorigenesis, were similar to those in inflammatory bowel disease (IBD) and human colon cancer. Additionally, we identified a specific transcriptional signature for the macrophage-FOXO3 axis (MAC-FOXO382), which separated the transcriptome of affected tissue from control in both IBD (p = 5.2 × 10−8 and colon cancer (p = 1.9 × 10−11), revealing its significance in human colonic pathobiologies. Further, we identified (heatmap) and validated (qPCR) DEGs specific to FOXO3-deficient macrophages with established roles both in IBD and colon cancer (IL-1B, CXCR2, S100A8, S100A9, and TREM1) and those with unexamined roles in these colonic pathobiologies (STRA6, SERPINH1, LAMB1, NFE2L3, OLR1, DNAJC28 and VSIG10). These findings establish an important understanding of how HFD obesity and related metabolites promote colonic pathobiologies.

Metabolism of tissue macrophages in homeostasis and pathology

Cellular metabolism orchestrates the intricate use of tissue fuels for catabolism and anabolism to generate cellular energy and structural components. The emerging field of immunometabolism highlights the importance of cellular metabolism for the maintenance and activities of immune cells. Macrophages are embryo- or adult bone marrow-derived leukocytes that are key for healthy tissue homeostasis but can also contribute to pathologies such as metabolic syndrome, atherosclerosis, fibrosis or cancer. Macrophage metabolism has largely been studied in vitro. However, different organs contain diverse macrophage populations that specialize in distinct and often tissue-specific functions. This context specificity creates diverging metabolic challenges for tissue macrophage populations to fulfill their homeostatic roles in their particular microenvironment and conditions their response in pathological conditions. Here, we outline current knowledge on the metabolic requirements and adaptations of macrophages located in tissues during homeostasis and selected diseases.

Pathophysiological Commonality Between Irritable Bowel Syndrome and Metabolic Syndrome: Role of Corticotropin-releasing Factor-Toll-like Receptor 4-Proinflammatory Cytokine Signaling

Irritable bowel syndrome (IBS) displays chronic abdominal pain with altered defecation. Most of the patients develop visceral hypersensitivity possibly resulting from impaired gut barrier and altered gut microbiota. We previously demonstrated that colonic hyperpermeability with visceral hypersensitivity in animal IBS models, which is mediated via corticotropin-releasing factor (CRF)-Toll-like receptor 4 (TLR4)-proinflammatory cytokine signaling. CRF impairs gut barrier via TLR4. Leaky gut induces bacterial translocation resulting in dysbiosis, and increases lipopolysaccharide (LPS). Activation of TLR4 by LPS increases the production of proinflammatory cytokines, which activate visceral sensory neurons to induce visceral hypersensitivity. LPS also activates CRF receptors to further increase gut permeability. Metabolic syndrome (MS) is a cluster of cardiovascular risk factors, including insulin resistance, obesity, dyslipidemia, and hypertension, and recently several researchers suggest the possibility that impaired gut barrier and dysbiosis with low-grade systemic inflammation are involved in MS. Moreover, TLR4-proinflammatory cytokine contributes to the development of insulin resistance and obesity. Thus, the existence of pathophysiological commonality between IBS and MS is expected. This review discusses the potential mechanisms of IBS and MS with reference to gut barrier and microbiota, and explores the possibility of existence of pathophysiological link between these diseases with a focus on CRF, TLR4, and proinflammatory cytokine signaling. We also review epidemiological data supporting this possibility, and discuss the potential of therapeutic application of the drugs used for MS to IBS treatment. This notion may pave the way for exploring novel therapeutic approaches for these disorders.

Adipose invariant NKT cells interact with CD1d-expressing macrophages to regulate obesity-related inflammation

Obesity is accompanied by and accelerated with chronic inflammation in adipose tissue, especially visceral adipose tissue (VAT). This low-level inflammation predisposes the host to the development of metabolic disease, most notably type 2 diabetes. We have focused on the capacity of glycolipid-reactive, CD1d-restricted natural killer T (NKT) cells to modulate obesity and its associated metabolic sequelae. We previously reported that CD1d knockout (KO) mice are partially protected against the development of obesity-associated insulin-resistance, and these findings were recapitulated in mice with an adipocyte-specific CD1d deficiency, suggesting that NKT cell-adipocyte interactions play a critical role in exacerbating disease. However, many other CD1d-expressing cells contribute to the in vivo responses of NKT cells to lipid antigens. In the present study, we examined the role of CD1d expression by macrophages (Mϕ) to the development of obesity-associated metabolic inflammation using LysMcre-cd1d1^f/f mice where the CD1d1 gene is disrupted in a Mϕ-specific manner. Unexpectedly, these animals contained a higher frequency of T-bet⁺ CD4⁺ T cells in VAT with increased production of Th1-cytokines that aggravated VAT inflammation. Mϕ from mutant mice displayed increased production of IL-12p40, suggesting M1 polarization. These findings indicate that interactions of CD1d on Mϕ with NKT cells play a beneficial role in obesity-associated VAT inflammation and insulin resistance with a sharp contrast to an aggravating role of CD1d on another type of antigen presenting cell, dendritic cells.

Is Arsenic Exposure a Risk Factor for Metabolic Syndrome? A Review of the Potential Mechanisms

Exposure to arsenic in drinking water is a worldwide health problem. This pollutant is associated with increased risk of developing chronic diseases, including metabolic diseases. Metabolic syndrome (MS) is a complex pathology that results from the interaction between environmental and genetic factors. This condition increases the risk of developing type 2 diabetes, cardiovascular diseases, and cancer. The MS includes at least three of the following signs, central obesity, impaired fasting glucose, insulin resistance, dyslipidemias, and hypertension. Here, we summarize the existing evidence of the multiple mechanisms triggered by arsenic to developing the cardinal signs of MS, showing that this pollutant could contribute to the multifactorial origin of this pathology.

Decreased ferroportin in hepatocytes promotes macrophages polarize towards an M2-like phenotype and liver fibrosis

Iron release from macrophages is closely regulated by the interaction of hepcidin, a peptide hormone produced by hepatocytes, with the macrophage iron exporter ferroportin (FPN1). However, the functions of FPN1 in hepatocyte secretion and macrophage polarization remain unknown. CD68 immunohistochemical staining and double immunofluorescence staining for F4/80 and Ki67 in transgenic mouse livers showed that the number of macrophages in FPN1^−/+ and FPN1^−/− mouse livers was significantly increased compared to that in WT (FPN^+/+) mice. FPN1 downregulation in hepatic cells increased the levels of the M2 markers CD206, TGF- β, VEGF, MMP-9, Laminin, Collagen, IL-4 and IL-10. Furthermore, the expression of CD16/32 and iNOS, as M1 markers, exhibited the opposite trend. Meanwhile, α-SMA immunohistochemistry and Sirius red staining showed that the trend of liver fibrosis in FPN1^−/− mice was more significant than that in control mice. Similarly, in vitro FPN1 knockdown in L02-Sh/L02-SCR liver cell lines yielded similar results. Taken together, we demonstrated that downregulated FPN1 expression in hepatocytes can promote the proliferation and polarization of macrophages, leading to hepatic fibrosis. Above all, the FPN1 axis might provide a potential target for hepatic fibrosis.

Visceral adipose tissue imparts peripheral macrophage influx into the hypothalamus

BACKGROUND

Obesity is characterized by a systemic inflammation and hypothalamic neuroinflammation. Systemic inflammation is caused by macrophages that infiltrate obese adipose tissues. We previously demonstrated that high-fat diet (HFD)-fed male mice exhibited peripheral macrophage infiltration into the hypothalamus, in addition to activation of resident microglia. Since this infiltration contributes to neuroinflammation and neuronal impairment, herein we characterize the phenotype and origin of these hypothalamic macrophages in HFD mice.

METHODS

C57BL/6J mice were fed HFD (60% kcal from fat) or control diet with matching sucrose levels, for 12-16 weeks. Males and females were analyzed separately to determine sex-specific responses to HFD. Differences in hypothalamic gene expression in HFD-fed male and female mice, compared to their lean controls, in two different areas of the hypothalamus, were determined using the NanoString neuroinflammation panel. Phenotypic changes in macrophages that infiltrated the hypothalamus in HFD-fed mice were determined by analyzing cell surface markers using flow cytometry and compared to changes in macrophages from the adipose tissue and peritoneal cavity. Adipose tissue transplantation was performed to determine the source of hypothalamic macrophages.

RESULTS

We determined that hypothalamic gene expression profiles demonstrate sex-specific and region-specific diet-induced changes. Sex-specific changes included larger changes in males, while region-specific changes included larger changes in the area surrounding the median eminence. Several genes were identified that may provide partial protection to female mice. We also identified diet-induced changes in macrophage migration into the hypothalamus, adipose tissue, and peritoneal cavity, specifically in males. Further, we determined that hypothalamus-infiltrating macrophages express pro-inflammatory markers and markers of metabolically activated macrophages that were identical to markers of adipose tissue macrophages in HFD-fed mice. Employing adipose tissue transplant, we demonstrate that hypothalamic macrophages can originate from the visceral adipose tissue.

CONCLUSION

HFD-fed males experience higher neuroinflammation than females, likely because they accumulate more visceral fat, which provides a source of pro-inflammatory macrophages that migrate to other tissues, including the hypothalamus. Our findings may explain the male bias for neuroinflammation and the metabolic syndrome. Together, our results demonstrate a new connection between the adipose tissue and the hypothalamus in obesity that contributes to neuroinflammation and hypothalamic pathologies.

Peripheral vascular disease: preclinical models and emerging therapeutic targeting of the vascular endothelial growth factor ligand-receptor system

Introduction: Vascular endothelial growth factor (VEGF)-A is a sought therapeutic target for PAD treatment because of its potent role in angiogenesis. However, no therapeutic benefit was achieved in VEGF-A clinical trials, suggesting that our understanding of VEGF-A biology and ischemic angiogenic processes needs development. Alternate splicing in VEGF-A produces pro- and anti-angiogenic VEGF-A isoforms; the only difference being a 6-amino acid switch in the C-terminus of the final 8th exon of the gene. This finding has changed our understanding of VEGF-A biology and may explain the lack of benefit in VEGF-A clinical trials. It presents new therapeutic opportunities for peripheral arterial disease (PAD) treatment.Areas covered: Literature search was conducted to include: 1) predicted mechanism by which the anti-angiogenic VEGF-A isoform would inhibit angiogenesis, 2) unexpected mechanism of action, and 3) how this mechanism revealed novel signaling pathways that may enhance future therapeutics in PAD.Expert opinion: Inhibiting a specific anti-angiogenic VEGF-A isoform in ischemic muscle promotes perfusion recovery in preclinical PAD. Additional efforts focused on the production of these isoforms, and the pathways altered by modulating different VEGF receptor-ligand interactions, and how this new data may allow bedside progress offers new approaches to PAD are discussed.I.

Involvements of long noncoding RNAs in obesity-associated inflammatory diseases

Obesity is associated with chronic low-grade inflammation that affects the phenotype of multiple tissues and therefore is implicated in the development and progression of several age-related chronic inflammatory disorders. Importantly, a new family of noncoding RNAs, termed long noncoding RNAs (lncRNAs), have been identified as key regulators of inflammatory signalling pathways that can mediate both pretranscriptional and posttranscriptional gene regulation. Furthermore, several lncRNAs have been identified, which are differentially expressed in multiple tissue types in individuals who are obese or in preclinical models of obesity. In this review, we examine the evidence for the role of several of the most well-studied lncRNAs in the regulation of inflammatory pathways associated with obesity. We highlight the evidence for their differential expression in the obese state and in age-related conditions including insulin resistance, type 2 diabetes (T2D), sarcopenia, osteoarthritis and rheumatoid arthritis, where obesity plays a significant role. Determining the expression and functional role of lncRNAs in mediating obesity-associated chronic inflammation will advance our understanding of the epigenetic regulatory pathways that underlie age-related inflammatory diseases and may also ultimately identify new targets for therapeutic intervention.

Microenvironmental Regulation of Macrophage Transcriptomic and Metabolomic Profiles in Pulmonary Hypertension

The recruitment and subsequent polarization of inflammatory monocytes/macrophages in the perivascular regions of pulmonary arteries is a key feature of pulmonary hypertension (PH). However, the mechanisms driving macrophage polarization within the adventitial microenvironment during PH progression remain unclear. We previously established that reciprocal interactions between fibroblasts and macrophages are essential in driving the activated phenotype of both cell types although the signals involved in these interactions remain undefined. We sought to test the hypothesis that adventitial fibroblasts produce a complex array of metabolites and proteins that coordinately direct metabolomic and transcriptomic re-programming of naïve macrophages to recapitulate the pathophysiologic phenotype observed in PH. Media conditioned by pulmonary artery adventitial fibroblasts isolated from pulmonary hypertensive (PH-CM) or age-matched control (CO-CM) calves were used to activate bone marrow derived macrophages. RNA-Seq and mass spectrometry-based metabolomics analyses were performed. Fibroblast conditioned medium from patients with idiopathic pulmonary arterial hypertension or controls were used to validate transcriptional findings. The microenvironment was targeted in vitro using a fibroblast-macrophage co-culture system and in vivo in a mouse model of hypoxia-induced PH. Both CO-CM and PH-CM actively, yet distinctly regulated macrophage transcriptomic and metabolomic profiles. Network integration revealed coordinated rewiring of pro-inflammatory and pro-remodeling gene regulation in concert with altered mitochondrial and intermediary metabolism in response to PH-CM. Pro-inflammation and metabolism are key regulators of macrophage phenotype in vitro, and are closely related to in vivo flow sorted lung interstitial/perivascular macrophages from hypoxic mice. Metabolic changes are accompanied by increased free NADH levels and increased expression of a metabolic sensor and transcriptional co-repressor, C-terminal binding protein 1 (CtBP1), a mechanism shared with adventitial PH-fibroblasts. Targeting the microenvironment created by both cell types with the CtBP1 inhibitor MTOB, inhibited macrophage pro-inflammatory and metabolic re-programming both in vitro and in vivo. In conclusion, coordinated transcriptional and metabolic reprogramming is a critical mechanism regulating macrophage polarization in response to the complex adventitial microenvironment in PH. Targeting the adventitial microenvironment can return activated macrophages toward quiescence and attenuate pathological remodeling that drives PH progression.

Proteomic screening identifies the direct targets of chrysin anti-lipid depot in adipocytes

ETHNOPHARMACOLOGICAL RELEVANCE

Overweight/obesity was mentioned by many countries as an obstacle to good health and long life, which increases risk of diseases and disorders. Previous studies suggested that the chronic low-grade inflammation present in the body was considered as the essential pathogenesis for obesity. Chrysin is extracted from traditional Chinese medicine Oroxylum indicum (Linn.) Kurz and plays a superior anti-obesity role. Chrysin could reduce the lipid depot by inhibiting the obesity-related inflammation in adipose tissue. However, the target protein for chrysin to exert its anti-obesity role are not verified.

AIM OF STUDY

The present study aimed to screen and validate the target protein for chrysin to reduce the lipid depot in palmitic acid-induced 3T3-L1 adipocytes.

MATERIALS AND METHODS

Obesity model was established employing 0.5 mmol/L palmitic acid-induced 3T3-L1 adipocytes through "Cocktails" method. Two-dimensional gel electrophoresis (2-DE) combined with liquid chromatography-mass spectrometry (LC-MS) was applied to analyze the differentially expressed proteins for chrysin intervention by lipid formation in adipocytes. Gene silencing was utilized to decrease gene expression of the candidate proteins, then production of triglyceride in 3T3-L1 was detected by triglycerides assay to determine the target proteins. Ultraviolet (UV) absorption together with fluorescence spectra validated the direct target proteins of chrysin. They also computed the correlation constants of combination between chrysin and the target proteins. Molecular docking was further employed to identify the main binding amino acids between chrysin and the target protein.

RESULTS

2-DE combined with LC-MS screened four candidate proteins which were related to metabolism and inflammation. The production of triglycerides in 3T3-L1 was reduced after decreasing gene expression of Annexin A2 (ANXA2), 60 kDa heat shock protein (HSP-60) and succinyl-CoA:3-ketoacid coenzyme A transferase 1 (SCOT-S), respectively. UV spectrum showed that the absorbance spectra of ANXA2 from 260 to 300 nm shifted upwards along with the increase in chrysin concentration, meanwhile the absorbance spectra of HSP-60 from 200 to 220 nm and from 265 to 280 nm shifted slightly upwards along with the increase in chrysin concentrations. The results indicated the conjugated structures between chrysin and ANXA2 or HSP-60. Fluorescence quenching further suggested a spontaneous interaction between chrysin and ANXA2 or HSP-60. Finally, molecular docking identified the main binding amino acids between ANXA2 and chrysin were Ser22, Tyr24, Pro267, Val298, Asp299, and Lys302.

CONCLUSIONS

Chrysin can reduce the amount of triglycerides by directly downregulating the inflammation-related target proteins ANXA2 and HSP-60, exerting an anti-obesity role.

Do polyunsaturated fatty acids protect against bone loss in our aging and osteoporotic population?

Age-related bone loss is inevitable in both men and women and there will soon be more people of extreme old age than ever before. Osteoporosis is a common chronic disease and as the proportion of older people, rate of obesity and the length of life increases, a rise in age-related degenerating bone diseases, disability, and prolonged dependency is projected. Fragility fractures are one of the most severe complications associated with both primary and secondary osteoporosis and current treatment strategies target weight-bearing exercise and pharmacological intervention, both with limited long-term success. Obesity and osteoporosis are intimately interrelated, and diet is a variable that plays a significant role in bone regeneration and repair. The Western Diet is characterized by its unhealthy components, specifically excess amounts of saturated fat intake. This review examines the impact of saturated and polyunsaturated fatty acid consumption on chronic inflammation, osteogenesis, bone architecture, and strength and explores the hypothesis that dietary polyunsaturated fats have a beneficial effect on osteogenesis, reducing bone loss by decreasing chronic inflammation, and activating bone resorption through key cellular and molecular mechanisms in our aging population. We conclude that aging, obesity and a diet high in saturated fatty acids significantly impairs bone regeneration and repair and that consumption of ω-3 polyunsaturated fatty acids is associated with significantly increased bone regeneration, improved microarchitecture and structural strength. However, ω-6 polyunsaturated fatty acids were typically pro-inflammatory and have been associated with an increased fracture risk. This review suggests a potential role for ω-3 fatty acids as a non-pharmacological dietary method of reducing bone loss in our aging population. We also conclude that contemporary amendments to the formal nutritional recommendations made by the Food and Nutrition Board may be necessary such that our aging population is directly considered.

Intervertebral Disc and Adipokine Leptin-Loves Me, Loves Me Not

Leptin—the most famous adipose tissue-secreted hormone—in the human body is mostly observed in a negative connotation, as the hormone level increases with the accumulation of body fat. Nowadays, fatness is becoming another normal body shape. Fatness is burdened with numerous illnesses—including low back pain and degenerative disease of lumbar intervertebral disc (IVD). IVD degeneration and IVD inflammation are two indiscerptible phenomena. Irrespective of the underlying pathophysiological background (trauma, obesity, nutrient deficiency), the inflammation is crucial in triggering IVD degeneration. Leptin is usually depicted as a proinflammatory adipokine. Many studies aimed at explaining the role of leptin in IVD degeneration, though mostly in in vitro and on animal models, confirmed leptin’s “bad reputation”. However, several studies found that leptin might have protective role in IVD metabolism. This review examines the current literature on the metabolic role of different depots of adipose tissue, with focus on leptin, in pathogenesis of IVD degeneration.

Sex Differences in Macrophage Responses to Obesity-Mediated Changes Determine Migratory and Inflammatory Traits

The mechanisms whereby obesity differentially affects males and females are unclear. Because macrophages are functionally the most important cells in obesity-induced inflammation, we sought to determine reasons for male-specific propensity in macrophage migration. We previously determined that male mice fed a high-fat diet exhibit macrophage infiltration into the hypothalamus, whereas females were protected irrespective of ovarian estrogen, in this study, we show that males accumulate more macrophages in adipose tissues that are also more inflammatory. Using bone marrow cells or macrophages differentiated in vitro from male and female mice fed control or high-fat diet, we demonstrated that macrophages derived from male mice are intrinsically more migratory. We determined that males have higher levels of leptin in serum and adipose tissue. Serum CCL2 levels, however, are the same in males and females, although they are increased in obese mice compared with lean mice of both sexes. Leptin receptor and free fatty acid (FFA) receptor, GPR120, are upregulated only in macrophages derived from male mice when cultured in the presence of FFA to mimic hyperlipidemia of obesity. Unless previously stimulated with LPS, CCL2 did not cause migration of macrophages. Leptin, however, elicited migration of macrophages from both sexes. Macrophages from male mice maintained migratory capacity when cultured with FFA, whereas female macrophages failed to migrate. Therefore, both hyperlipidemia and hyperleptinemia contribute to male macrophage-specific migration because increased FFA induce leptin receptors, whereas higher leptin causes migration. Our results may explain sex differences in obesity-mediated disorders caused by macrophage infiltration.

Myeloid Krüppel-like factor 2 is a critical regulator of metabolic inflammation

Substantial evidence implicates crosstalk between metabolic tissues and the immune system in the inception and progression of obesity. However, molecular regulators that orchestrate metaflammation both centrally and peripherally remains incompletely understood. Here, we identify myeloid Krüppel-like factor 2 (KLF2) as an essential regulator of obesity and its sequelae. In mice and humans, consumption of a fatty diet downregulates myeloid KLF2 levels. Under basal conditions, myeloid-specific KLF2 knockout mice (K2KO) exhibit increased feeding and weight gain. High-fat diet (HFD) feeding further exacerbates the K2KO metabolic disease phenotype. Mechanistically, loss of myeloid KLF2 increases metaflammation in peripheral and central tissues. A combination of pair-feeding, bone marrow-transplant, and microglial ablation implicate central and peripheral contributions to K2KO-induced metabolic dysfunction observed. Finally, overexpression of myeloid KLF2 protects mice from HFD-induced obesity and insulin resistance. Together, these data establish myeloid KLF2 as a nodal regulator of central and peripheral metabolic inflammation in homeostasis and disease.

Inflammation contributes to the development of metabolic disease through incompletely understood mechanisms. Here the authors report that deletion of the transcription factor KLF2 in myeloid cells leads to increased feeding and weight gain in mice with concomitant peripheral and central tissue inflammation, while overexpression protects against diet-induced metabolic disease.

Changes in Function and Dynamics in Hepatic and Splenic Macrophages in Non-Alcoholic Fatty Liver Disease

Background

The aim of this study was to investigate the populations and functions of hepatic and splenic macrophages (Mfs) in non-alcoholic fatty liver disease (NAFLD).

Materials and Methods

Experiment 1: Wild-type and STAM^® mice were given chow or high-fat diets for designated periods. In isolated Mfs, phagocytosis and cytokine production were assessed. Immunohistochemistry for CD68 and F4/80 and expression of CD14 and CD16 were assessed. Experiment 2: Bone marrow cells harvested from enhanced green fluorescent protein (EGFP) mice were transplanted into wild-type mice with or without splenectomy after total body irradiation that was kept on methionine- and choline-deficient diets.

Results

Experiment 1: The number of CD68-positive cells and the percentage of F4/80-positive/CD68-positive cells increased with the progression of NAFLD. Production of TNF-α and IL-6 by hepatic Mfs was greater than that by splenic Mfs in mice with NASH. The number of CD14⁺CD16⁻ Mfs increased in the spleen and decreased in the liver in animals that had progressed to NASH. Furthermore, the number of CD14⁺CD16⁺ hepatic Mfs was increased in animals that had progressed to NASH with fibrosis. Experiment 2: EGFP-positive cells were observed in the liver after transplantation. In the splenectomy group, EGFP-positive Mfs were also observed; however, the number was significantly less than that in the sham operation group.

Conclusion

The populations and functions of hepatic and splenic Mfs are altered during the progression of NAFLD. In addition, increased hepatic Mfs during the progression of NAFLD may migrate from bone marrow to the liver via the spleen.

Schistosome and intestinal helminth modulation of macrophage immunometabolism

Macrophages are fundamental to sustain physiological equilibrium and to regulate the pathogenesis of parasitic and metabolic processes. The functional heterogeneity and immune responses of macrophages are shaped by cellular metabolism in response to the host's intrinsic factors, environmental cues and other stimuli during disease. Parasite infections induce a complex cascade of cytokines and metabolites that profoundly remodel the metabolic status of macrophages. In particular, helminths polarize macrophages to an M2 state and induce a metabolic shift towards reliance on oxidative phosphorylation, lipid oxidation and amino acid metabolism. Accumulating data indicate that helminth-induced activation and metabolic reprogramming of macrophages underlie improvement in overall whole-body metabolism, denoted by improved insulin sensitivity, body mass in response to high-fat diet and atherogenic index in mammals. This review aims to highlight the metabolic changes that occur in human and murine-derived macrophages in response to helminth infections and helminth products, with particular interest in schistosomiasis and soil-transmitted helminths.

Fate of Adipose Progenitor Cells in Obesity-Related Chronic Inflammation

Adipose progenitor cells, or preadipocytes, constitute a small population of immature cells within the adipose tissue. They are a heterogeneous group of cells, in which different subtypes have a varying degree of commitment toward diverse cell fates, contributing to white and beige adipogenesis, fibrosis or maintenance of an immature cell phenotype with proliferation capacity. Mature adipocytes as well as cells of the immune system residing in the adipose tissue can modulate the function and differentiation potential of preadipocytes in a contact- and/or paracrine-dependent manner. In the course of obesity, the accumulation of immune cells within the adipose tissue contributes to the development of a pro-inflammatory microenvironment in the tissue. Under such circumstances, the crosstalk between preadipocytes and immune or parenchymal cells of the adipose tissue may critically regulate the differentiation of preadipocytes into white adipocytes, beige adipocytes, or myofibroblasts, thereby influencing adipose tissue expansion and adipose tissue dysfunction, including downregulation of beige adipogenesis and development of fibrosis. The present review will outline the current knowledge about factors shaping cell fate decisions of adipose progenitor cells in the context of obesity-related inflammation.

The Intricate Relationship between Type 2 Diabetes Mellitus (T2DM), Insulin Resistance (IR), and Nonalcoholic Fatty Liver Disease (NAFLD)

Nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM) remain as one of the most global problematic metabolic diseases with rapidly increasing prevalence and incidence. Epidemiological studies noted that T2DM patients have by two-fold increase to develop NAFLD, and vice versa. This complex and intricate association is supported and mediated by insulin resistance (IR). In this review, we discuss the NAFLD immunopathogenesis, connection with IR and T2DM, the role of screening and noninvasive tools, and mostly the impact of the current antidiabetic drugs on steatosis liver and new potential therapeutic targets.