A New Strategy for Obesity Treatment: Revealing the Frontiers of Anti-obesity Medications.

Obesity dramatically increases the risk of type 2 diabetes, fatty liver, hypertension, cardiovascular disease, and cancer, causing both declines in quality of life and life expectancy, which is a serious worldwide epidemic. At present, more and more patients with obesity are choosing drug therapy. However, given the high failure rate, high cost, and long design and testing process for discovering and developing new anti-obesity drugs, drug repurposing could be an innovative method and opportunity to broaden and improve pharmacological tools in this context. Because different diseases share molecular pathways and targets in the cells, anti-obesity drugs discovered in other fields are a viable option for treating obesity. Recently, some drugs initially developed for other diseases, such as treating diabetes, tumors, depression, alcoholism, erectile dysfunction, and Parkinson's disease, have been found to exert potential anti-obesity effects, which provides another treatment prospect. In this review, we will discuss the potential benefits and barriers associated with these drugs being used as obesity medications by focusing on their mechanisms of action when treating obesity. This could be a viable strategy for treating obesity as a significant advance in human health.

miR-32-5p induces hepatic steatosis and hyperlipidemia by triggering de novo lipogenesis.

BACKGROUND AND OBJECTIVES: MicroRNA-dependent regulation of hepatic lipid metabolism has been recognized recently as a key pathological mechanism contributing to the development of NAFLD. However, whether miR-32-5p (miR-32) plays a role in lipid metabolism or contributes to NAFLD remains unclear. METHODS AND RESULTS: A marked increase in miR-32 expression was observed in liver samples from patients and mice with NAFLD, as well as in palmitate-induced hepatocytes. Hepatocyte-specific miR-32 knockout (miR-32-HKO) dramatically ameliorated hepatic steatosis and metabolic disorders in high-fat diet-fed mice. Conversely, hepatic miR-32 overexpression markedly exacerbated the progression of these abnormalities. Further, combinational analysis of transcriptomics and lipidomics suggested that miR-32 was a key trigger for de novo lipogenesis in the liver. Mechanistically, RNA sequencing, luciferase assay and adenovirus-mediated downstream gene rescue assay demonstrated that miR-32 directly bound to insulin-induced gene 1 (INSIG1) and subsequently activated sterol regulatory element binding protein-mediated lipogenic gene programs, thereby promoting hepatic lipid accumulation and metabolic disorders. Notably, pharmacological administration of miR-32 antagonist significantly inhibited palmitate-induced triglyceride deposition in hepatocytes and markedly mitigated hepatic steatosis and metabolic abnormalities in obesity-associated NAFLD mice. CONCLUSION: miR-32 is an important checkpoint for lipogenesis in the liver, and targeting miR-32 could be a promising therapeutic approach for NAFLD treatment.

Organokines and Exosomes: Integrators of Adipose Tissue Macrophage Polarization and Recruitment in Obesity.

The prevalence of obesity is escalating and has become a worldwide health challenge coinciding with the development of metabolic diseases. Emerging evidence has shown that obesity is accompanied by the infiltration of macrophages into adipose tissue, contributing to a state of low-grade chronic inflammation and dysregulated metabolism. Moreover, in the state of obesity, the phenotype of adipose tissue macrophages switches from the M2 polarized state to the M1 state, thereby contributing to chronic inflammation. Notably, multiple metabolic organs (adipose tissue, gut, skeletal muscle, and the liver) communicate with adipose tissue macrophages via secreting organokines or exosomes. In this review, we systematically summarize how the organokines (adipokines, gut microbiota and its metabolites, gut cytokines, myokines, and hepatokines) and exosomes (adipocyte-, skeletal muscle-, and hepatocyte-derived exosomes) act as important triggers for macrophage recruitment in adipose tissue and adipose tissue macrophage polarization, thus providing further insight into obesity treatment. In addition, we also highlight the complex interaction of organokines with organokines and organokines with exosomes, revealing new paths in understanding adipose tissue macrophage recruitment and polarization.

Exogenous Hydrogen Sulfide Alleviates-Induced Intracellular Inflammation in HepG2 Cells.

Fatty acids induced hepatic inflammation plays an important role in nonalcoholic fatty liver disease (NAFLD) pathogenesis. Hydrogen sulfide (H2S), an endogenous gasotransmitter, has been established to possess potent anti-inflammation in various human organs. However, the anti-inflammation property of H2S in the fatty liver is still needed to further elucidate. Hence, this study aimed to investigate whether exogenous H2S can protect hepatocytes against inflammation induced by palmitic acid (PA). HepG2 hepatocytes were exposed to PA for 24 h to induce free fatty acids-induced inflammation. The cells were pretreated with NaHS (a donor of H2S) before exposure to PA. Cell viability, inflammatory cytokines (TNF-α, IL-6 and IL-1ß), NLRP3 inflammasome and NF-κB were measured by a combination of MTT assay, ELISA, Western blot and Immunofluorescence. Here, we found that exogenous H2S dose-dependently inhibited the expression of pro-inflammatory cytokines, NLRP3 inflammasome and activation of NF-κB signaling in PA-induced HepG2 cells. Thus, H2S might be a candidate therapeutic agent against NAFLD.

Serum CCN3 levels are increased in type 2 diabetes mellitus and associated with obesity, insulin resistance and inflammation.

BACKGROUD: CCN3 is a novel adipokine and has emerged as a potential metabolic regulator. However, information regarding the role of CCN3 in type 2 diabetes mellitus (T2DM) remains unclear. This study measured for the first time serum CCN3 levels in T2DM and explored the correlations between its serum levels and various metabolic parameters in humans. METHODS: A total of 219 newly diagnosed T2DM (nT2DM) patients and 205 healthy control subjects, matched for age and sex ratio, were enrolled. Circulating CCN3 and TNF-α, IL-6 and MCP-1 were measured by ELISA. The anthropometric assessment and biochemical evaluation were done in all subjects. OGTT were performed in 34 healthy individuals to investigate the association of CCN3 with glucose. RESULTS: Serum CCN3 levels were significantly higher in nT2DM patients compared to those of the healthy controls (6.71[4.88, 8.56] vs. 4.51[3.55, 5.99] ng/ml, P < 0.01). Serum CCN3 positively correlated with BMI, WC, FAT%, TG, FPG, 2 h-PG, HbA1c, FIns, HOMA-IR, hs-CRP and TNF-α, IL-6 and MCP-1, but negatively with HOMA-ß in all individuals (P < 0.05). Multiple linear regression analysis indicated that BMI, HOMA-IR, TNF-α and MCP-1 were independently associated with CCN3. Multivariate logistic regression analysis demonstrated that CCN3 was correlated with nT2DM. Finally, area under ROC curve of CCN3 (gender and age adjusted) for predicting the presence of nT2DM was 0.725(95% CI: 0.676-0.773). After an oral glucose challenge, there was no obvious change in the circulating levels of CCN3 as compared to 0 min (P > 0.05). CONCLUSIONS: Elevation of CCN3 in nT2DM supports the hypothesis that CCN3 may serve as a risk factor associated with the pathogenesis of T2DM.

Zinc alpha2 glycoprotein protects against obesity-induced hepatic steatosis.

BACKGROUND/AIM: Nonalcoholic fatty liver disease (NAFLD) is characterized by hepatic steatosis, impaired insulin sensitivity, and chronic low-grade inflammation. Our previous studies indicated that zinc alpha2 glycoprotein (ZAG) alleviates palmitate (PA)-induced intracellular lipid accumulation in hepatocytes. This study is to further characterize the roles of ZAG on the development of hepatic steatosis, insulin resistance (IR), and inflammation. METHODS: ZAG protein levels in the livers of NAFLD patients, high-fat diet (HFD)-induced or genetically (ob/ob) induced obese mice, and in PA-treated hepatocytes were determined by western blotting. C57BL/6J mice injected with an adenovirus expressing ZAG were fed HFD for indicated time to induce hepatic steatosis, IR, and inflammation, and then biomedical, histological, and metabolic analyses were conducted to identify pathologic alterations in these mice. The molecular mechanisms underlying ZAG-regulated hepatic steatosis were further explored and verified in mice and hepatocytes. RESULTS: ZAG expression was decreased in NAFLD patient liver biopsy samples, obese mice livers, and PA-treated hepatocytes. Simultaneously, ZAG overexpression alleviated intracellular lipid accumulation via upregulating adiponectin and lipolytic genes (FXR, PPARα, etc.) while downregulating lipogenic genes (SREBP-1c, LXR, etc.) in obese mice as well as in cultured hepatocytes. ZAG improved insulin sensitivity and glucose tolerance via activation of IRS/AKT signaling. Moreover, ZAG significantly inhibited NF-ĸB/JNK signaling and thus resulting in suppression of obesity-associated inflammatory response in hepatocytes. CONCLUSIONS: Our results revealed that ZAG could protect against NAFLD by ameliorating hepatic steatosis, IR, and inflammation.