Adiponectin-derived active peptide ADP355 exerts anti-inflammatory and anti-fibrotic activities in thioacetamide-induced liver injury

The adiponectin-derived peptide ALY688 protects against the development of metabolic dysfunction-associated steatohepatitis

Metabolic dysfunction-associated steatohepatitis (MASH) is the severe form of non-alcoholic fatty liver disease which has a high potential to progress to cirrhosis and hepatocellular carcinoma, yet adequate effective therapies are lacking. Hypoadiponectinemia is causally involved in the pathogenesis of MASH. This study investigated the pharmacological effects of adiponectin replacement therapy with the adiponectin-derived peptide ALY688 (ALY688-SR) in a mouse model of MASH. Human induced pluripotent stem (iPS) cell-derived hepatocytes were used to test cytotoxicity and signaling of unmodified ALY688 in vitro. High-fat diet with low methionine and no added choline (CDAHF) was used to induce MASH and test the effects of ALY688-SR in vivo. Histological MASH activity score (NAS) and fibrosis score were determined to assess the effect of ALY688-SR. Transcriptional characterization of mice through RNA sequencing was performed to indicate potential molecular mechanisms involved. In cultured hepatocytes, ALY688 efficiently induced adiponectin-like signaling, including the AMP-activated protein kinase and p38 mitogen-activated protein kinase pathways, and did not elicit cytotoxicity. Administration of ALY688-SR in mice did not influence body weight but significantly ameliorated CDAHF-induced hepatic steatosis, inflammation, and fibrosis, therefore effectively preventing the development and progression of MASH. Mechanistically, ALY688-SR treatment markedly induced hepatic expression of genes involved in fatty acid oxidation, whereas it significantly suppressed the expression of pro-inflammatory and pro-fibrotic genes as demonstrated by transcriptomic analysis. ALY688-SR may represent an effective approach in MASH treatment. Its mode of action involves inhibition of hepatic steatosis, inflammation, and fibrosis, possibly via canonical adiponectin-mediated signaling.

Namodenoson at the Crossroad of Metabolic Dysfunction-Associated Steatohepatitis and Hepatocellular Carcinoma

Namodenoson (CF102) is a small, orally available, anti-inflammatory, and anti-cancer drug candidate currently in phase 2B trial for the treatment of metabolic dysfunction-associated steatohepatitis (MASH; formerly known as non-alcoholic steatohepatitis (NASH)) and in phase 3 pivotal clinical trial for the treatment of hepatocellular carcinoma (HCC). In both MASH and HCC, the mechanism-of-action of namodenoson involves targeting the A3 adenosine receptor (A3AR), resulting in deregulation of downstream signaling pathways and leading to inhibition of inflammatory cytokines (TNF-α, IL-1, IL-6, and IL-8) and stimulation of positive cytokines (G-CSF and adiponectin). Subsequently, inhibition of liver inflammation, steatosis, and fibrosis were documented in MASH experimental models, and inhibition of HCC growth was observed in vitro, in vivo, and in clinical studies. This review discusses the evidence related to the multifaceted mechanism of action of namodenoson, and how this mechanism is reflected in the available clinical data in MASH and HCC.

The slow-release adiponectin analog ALY688-SR modifies early-stage disease development in the D2.mdx mouse model of Duchenne muscular dystrophy

Fibrosis is associated with respiratory and limb muscle atrophy in Duchenne muscular dystrophy (DMD). Current standard of care partially delays the progression of this myopathy but there remains an unmet need to develop additional therapies. Adiponectin receptor agonism has emerged as a possible therapeutic target to lower inflammation and improve metabolism in mdx mouse models of DMD but the degree to which fibrosis and atrophy are prevented remain unknown. Here, we demonstrate that the recently developed slow-release peptidomimetic adiponectin analog, ALY688-SR, remodels the diaphragm of murine model of DMD on DBA background (D2.mdx) mice treated from days 7-28 of age during early stages of disease. ALY688-SR also lowered interleukin-6 (IL-6) mRNA but increased IL-6 and transforming growth factor-β1 (TGF-β1) protein contents in diaphragm, suggesting dynamic inflammatory remodeling. ALY688-SR alleviated mitochondrial redox stress by decreasing complex I-stimulated H2O2 emission. Treatment also attenuated fibrosis, fiber type-specific atrophy, and in vitro diaphragm force production in diaphragm suggesting a complex relationship between adiponectin receptor activity, muscle remodeling, and force-generating properties during the very early stages of disease progression in murine model of DMD on DBA background (D2.mdx) mice. In tibialis anterior, the modest fibrosis at this young age was not altered by treatment, and atrophy was not apparent at this young age. These results demonstrate that short-term treatment of ALY688-SR in young D2.mdx mice partially prevents fibrosis and fiber type-specific atrophy and lowers force production in the more disease-apparent diaphragm in relation to lower mitochondrial redox stress and heterogeneous responses in certain inflammatory markers. These diverse muscle responses to adiponectin receptor agonism in early stages of DMD serve as a foundation for further mechanistic investigations.NEW & NOTEWORTHY There are limited therapies for the treatment of Duchenne muscular dystrophy. As fibrosis involves an accumulation of collagen that replaces muscle fibers, antifibrotics may help preserve muscle function. We report that the novel adiponectin receptor agonist ALY688-SR prevents fibrosis in the diaphragm of D2.mdx mice with short-term treatment early in disease progression. These responses were related to altered inflammation and mitochondrial functions and serve as a foundation for the development of this class of therapy.

AdipoRon and ADP355, adiponectin receptor agonists, in Metabolic-associated Fatty Liver Disease (MAFLD) and Nonalcoholic Steatohepatitis (NASH): A systematic review

Adiponectin replacement therapy holds the potential to benefit numerous human diseases, and ongoing research applies particular interest in how adiponectin acts against Metabolic-associated Fatty Liver Disease (MAFLD) and Nonalcoholic Steatohepatitis (NASH). However, the pharmacological limitations of the intact protein have prompted a focus on alternative options, specifically peptidic and small molecule agonists targeting the adiponectin receptor. AdipoRon is an extensively researched non-peptidic drug candidate in adiponectin replacement therapy. In turn, ADP355 is an adiponectin-based active short peptide. They have garnered significant attention due to their potential as substitutes for adiponectin. Researchers have studied AdipoRon's and ADP355's efficacy and therapeutic applications in various disease conditions. However, the effects of AdipoRon and ADP355 against NAFLD and NASH models advanced more, and no systematic review explored this area before. This systematic review was conceived to address the deficiency mentioned above and consider the lack of clinical evidence. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were utilized. To assess the risk of bias in systematic review, The Joanna Briggs Institute (JBI) Critical Appraisal Checklist was employed. Results from pre-clinical evidence show that AdipoRon and ADP355 represent promising effects in NAFLD and NASH-related models, including reducing hepatic steatosis, modulating inflammation, improving insulin sensitivity, enhancing mitochondrial function, and protecting against liver fibrosis. While AdipoRon and ADP355 exhibit promise in pre-clinical studies and experimental models, additional clinical trials are necessary to assess their effectiveness, safety, and potential translational therapeutic potential uses in NAFLD and NASH human cases.

Simultaneous intervention against oxidative stress and inflammation by targeting Nrf2/ARE and NLRP3 inflammasome pathway mitigates thioacetamide-induced liver fibrosis in rat

Liver fibrosis is a typical pathological state/stage involved in most chronic liver diseases and its persistence results in cirrhosis. Inflammasomes are cytoplasmic sensors that induce inflammation in response to stress. Glibenclamide (GLB) is an USFDA-approved drug for type 2 diabetes and is reported to possess anti-inflammatory activity by inhibiting inflammatory cytokines. Dimethyl fumarate (DMF) is an USFDA-approved drug for multiple sclerosis and has been reported to activate the Nrf2/ARE pathway to maintain the cellular antioxidant balance. A total of 36 rats were randomized into six groups (n = 6 each). The rats were injected with thioacetamide (TAA) 200 mg/kg, intraperitoneally every third day for eight consecutive weeks to induce liver fibrosis and oral treatment of GLB 0.5 mg/kg/day and DMF 25 mg/kg/day, and their combinations were provided for the last four consecutive weeks. Treatment with GLB, DMF, and GLB+DMF significantly protected against TAA-mediated oxidative stress and inflammatory conditions by improving hepatic function test, triglycerides, hydroxyproline, and histopathological alterations, by inhibiting the NLRP3 inflammasome signaling and fibrogenic markers, and by activating Nrf2/ARE pathway in Wistar rats. The present results suggest that simultaneous Nrf2/ARE activation and NLRP3 inflammasome inhibition could significantly contribute to developing a novel therapy for patients with liver fibrosis.

Memory impairment in the D2.mdx mouse model of Duchenne muscular dystrophy is prevented by the adiponectin receptor agonist ALY688

NEW FINDINGS

What is the central question of this study? Can adiponectin receptor agonism improve recognition memory in a mouse model of Duchenne muscular dystrophy? What is the main finding and its importance? Short-term treatment with the new adiponectin receptor agonist ALY688 improves recognition memory in D2.mdx mice. This finding suggests that further investigation into adiponectin receptor agonism is warranted, given that there remains an unmet need for clinical approaches to treat this cognitive dysfunction in people with Duchenne muscular dystrophy.

ABSTRACT

Memory impairments have been well documented in people with Duchenne muscular dystrophy (DMD). However, the underlying mechanisms are poorly understood, and there is an unmet need to develop new therapies to treat this condition. Using a novel object recognition test, we show that recognition memory impairments in D2.mdx mice are completely prevented by daily treatment with the new adiponectin receptor agonist ALY688 from day 7 to 28 of age. In comparison to age-matched wild-type mice, untreated D2.mdx mice demonstrated lower hippocampal mitochondrial respiration (carbohydrate substrate), greater serum interleukin-6 cytokine content and greater hippocampal total tau and Raptor protein contents. Each of these measures was partly or fully preserved after treatment with ALY688. Collectively, these results indicate that adiponectin receptor agonism improves recognition memory in young D2.mdx mice.

The Adiponectin Receptor Agonist, ALY688: A Promising Therapeutic for Fibrosis in the Dystrophic Muscle

Duchenne muscular dystrophy (DMD) is one of the most devastating myopathies, where severe inflammation exacerbates disease progression. Previously, we demonstrated that adiponectin (ApN), a hormone with powerful pleiotropic effects, can efficiently improve the dystrophic phenotype. However, its practical therapeutic application is limited. In this study, we investigated ALY688, a small peptide ApN receptor agonist, as a potential novel treatment for DMD. Four-week-old mdx mice were subcutaneously treated for two months with ALY688 and then compared to untreated mdx and wild-type mice. In vivo and ex vivo tests were performed to assess muscle function and pathophysiology. Additionally, in vitro tests were conducted on human DMD myotubes. Our results showed that ALY688 significantly improved the physical performance of mice and exerted potent anti-inflammatory, anti-oxidative and anti-fibrotic actions on the dystrophic muscle. Additionally, ALY688 hampered myonecrosis, partly mediated by necroptosis, and enhanced the myogenic program. Some of these effects were also recapitulated in human DMD myotubes. ALY688's protective and beneficial properties were mainly mediated by the AMPK-PGC-1α axis, which led to suppression of NF-κβ and TGF-β. Our results demonstrate that an ApN mimic may be a promising and effective therapeutic prospect for a better management of DMD.

Cardiac Hepatopathy: New Perspectives on Old Problems through a Prism of Endogenous Metabolic Regulations by Hepatokines

Cardiac hepatopathy refers to acute or chronic liver damage caused by cardiac dysfunction in the absence of any other possible causative reasons of liver injury. There is a large number of evidence of the fact that cardiac hepatopathy is associated with poor clinical outcomes in patients with acute or actually decompensated heart failure (HF). However, the currently dominated pathophysiological background does not explain a role of metabolic regulative proteins secreted by hepatocytes in progression of HF, including adverse cardiac remodeling, kidney injury, skeletal muscle dysfunction, osteopenia, sarcopenia and cardiac cachexia. The aim of this narrative review was to accumulate knowledge of hepatokines (adropin; fetuin-A, selenoprotein P, fibroblast growth factor-21, and alpha-1-microglobulin) as adaptive regulators of metabolic homeostasis in patients with HF. It is suggested that hepatokines play a crucial, causative role in inter-organ interactions and mediate tissue protective effects counteracting oxidative stress, inflammation, mitochondrial dysfunction, apoptosis and necrosis. The discriminative potencies of hepatokines for HF and damage of target organs in patients with known HF is under on-going scientific discussion and requires more investigations in the future.

A 67-bp variable duplication in the promoter region of the ADIPOQ is associated with milk traits in Xinjiang brown cattle

Adiponectin, also known as ADIPOQ, is a hormone protein secreted by adipocytes. The ADIPOQ gene is expressed primarily in adipose tissue, and the encoded protein circulates in the bloodstream and has the potential to regulate both animal fat metabolism and hormone production. Our previous work uncovered a 67-bp variable duplication in the promoter region of ADIPOQ, which reduced the basal transcriptional activity of ADIPOQ in the 3T3_L1 cell and also inhibits the ADIPOQ mRNA expression in adipose tissue. Accordingly, the present study aimed to identify the relationship between the 67-bp structural variations in ADIPOQ promoter region and the milk traits of Xinjiang brown cattle (XJBC). The results revealed two genotypes, DD and ID, in the XJBC, and minor allelic frequency (MAF) for the 'I' allele was more than 1%. Moreover, the association analysis revealed that the 67-bp duplication in the promoter region of the ADIPOQ gene was significantly correlated with the 305 days of milk production volume, fat yield, and milk fat percentage in the XJBC (p < 0.05). These results obtained in this study suggested that the identified variable duplication could be considered as the potential genetic marker for improving milk traits of XJBC.

Development, validation, and application of an UHPLC-MS/MS method for quantification of the adiponectin-derived active peptide ADP355 in rat plasma

An UHPLC-MS/MS method for quantification of ADP355, an adiponectin-derived active peptide, was developed and validated. The extraction method employed simple protein precipitation using methanol and the chromatographic separation was achieved on the Accucore™ RP-MS C18 column (100 × 2.1mm, 2.6 μm, 80 Å), using 0.1% formic acid in both water and acetonitrile with gradient elution at the flow rate of 400 μL/min within 4.0 min. Detections were performed under positive ion mode with MRM ion transitions m/z 1109.2→309.8 and 871.4→310.1 for ADP355 and Jt003 respectively at unit resolution. The linearity range of the calibration curve was 2-1000 ng/mL with lower limit detection of 0.5 ng/mL. Selectivity, linearity, precision, accuracy, recovery, matrix effect, and stability were validated, and all items met the requirement of FDA guidance. This method has been successfully applied to an intravenous pharmacokinetic study of ADP355 in rats and the in-vitro stability in rat serum, plasma, and whole blood was also assessed.

Simultaneous Modulation of NLRP3 Inflammasome and Nrf2/ARE Pathway Rescues Thioacetamide-Induced Hepatic Damage in Mice: Role of Oxidative Stress and Inflammation

Chronic tissue injury resulting in fibrosis of multiple organs, responsible for one-third of the death globally. Liver fibrosis is a common pathway/condition involved in all chronic liver diseases. Thioacetamide (TAA), a hepatotoxicant, was used to induce hepatic fibrosis. Anti-diabetic drug glibenclamide (GLB) possesses anti-inflammatory properties and inhibits NACHT, LRR, and PYD domains-containing protein 3 (NLRP3) inflammasome activation. Dimethyl fumarate (DMF), a multiple sclerosis drug, activates the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway and maintains the antioxidant status in the cell. The present study was designed to investigate (i) role of NLRP3 inflammasome and Nrf2/ARE pathway in TAA-induced hepatotoxicity and liver fibrosis, (ii) mechanism involved in GLB and DMF mediated hepatoprotection against TAA-induced hepatotoxicity, and (iii) additional/synergistic hepatoprotective effect of combination treatment with NLRP3 inhibition + Nrf2 activation or GLB + DMF or MCC950 + 4OI to reverse/ameliorate the experimental liver fibrosis completely. TAA was administered intraperitoneally to mice for seven consecutive weeks, and treatments of GLB, DMF, GLB + DMF, MCC950, 4OI, and MCC950 + 4OI were provided for the last three consecutive weeks. The intervention with GLB, DMF, GLB + DMF, MCC950, 4OI, and MCC950 + 4OI significantly protected TAA-induced oxidative stress and inflammatory conditions by improving biochemical, histological, and immunoexpression changes in mice. The GLB, DMF, and GLB + DMF intervention exhibited a better protective effect compared with MCC950, 4OI, and MCC950 + 4OI, which revealed that this specific inhibitor/activator possesses only NLRP3 inflammasome inhibitory/Nrf2 activatory properties. In contrast, the clinical drug GLB and DMF have several other beneficial effects, which are independent of NLRP3 inhibition and Nrf2 activation.

The Controversial Role of Adiponectin in Appetite Regulation of Animals

Eating disorders and obesity are important health problems with a widespread global epidemic. Adiponectin (AdipoQ), the most abundant adipokine in the plasma, plays important roles in the regulation of energy homeostasis, glucose metabolism and lipid metabolism. Plasma adiponectin concentration is negatively associated with obesity and binge eating disorder. There is a growing interest in the appetite regulation function of adiponectin. However, the effect of AdipoQ on feeding behavior is controversial and closely related to nutritional status and food composition. In this review, we summarize the literatures about the discovery, structure, tissue distribution, receptors and regulation of nutritional status, and focus on the biological function of adiponectin in the regulation of food intake in the central and peripheral system.

Adiponectin's globular domain inhibits T cell activation by interacting with LAIR-1

Adiponectin (APN) is the most abundant adipokine in human plasma, and has insulin-sensitizing effect. Recent studies have reported that APN plays both anti- and pro-inflammatory roles under different circumstances. However, there is a lack of convincing evidence that decipher APN's anti-inflammatory role through the known receptors and their downstream signaling pathways. In this study, we evaluated a new molecular mechanism underlying APN's anti-inflammatory roles. Our results revealed that the globular domain of adiponectin (gAdp) interacted with the inhibitory leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1). In vitro experiments showed that gAdp inhibited activation of the T cells via the LAIR-1, through a process that also involved downstream SHP-2. These findings indicate that LAIR-1 is a novel APN receptor, affirming APN's anti-inflammatory effect. In summary, we have identified a novel mechanism of peripheral immunoregulatory processes that provides baseline information for further studies on gAdp's role and its contribution to inflammation.

Association of Adipose Tissue and Adipokines with Development of Obesity-Induced Liver Cancer

Obesity is rapidly dispersing all around the world and is closely associated with a high risk of metabolic diseases such as insulin resistance, dyslipidemia, and nonalcoholic fatty liver disease (NAFLD), leading to carcinogenesis, especially hepatocellular carcinoma (HCC). It results from an imbalance between food intake and energy expenditure, leading to an excessive accumulation of adipose tissue (AT). Adipocytes play a substantial role in the tumor microenvironment through the secretion of several adipokines, affecting cancer progression, metastasis, and chemoresistance via diverse signaling pathways. AT is considered an endocrine organ owing to its ability to secrete adipokines, such as leptin, adiponectin, resistin, and a plethora of inflammatory cytokines, which modulate insulin sensitivity and trigger chronic low-grade inflammation in different organs. Even though the precise mechanisms are still unfolding, it is now established that the dysregulated secretion of adipokines by AT contributes to the development of obesity-related metabolic disorders. This review focuses on several obesity-associated adipokines and their impact on obesity-related metabolic diseases, subsequent metabolic complications, and progression to HCC, as well as their role as potential therapeutic targets. The field is rapidly developing, and further research is still required to fully understand the underlying mechanisms for the metabolic actions of adipokines and their role in obesity-associated HCC.

AdipoR1/AdipoR2 dual agonist recovers nonalcoholic steatohepatitis and related fibrosis via endoplasmic reticulum-mitochondria axis

Chronic nonalcoholic steatohepatitis (NASH) is a metabolic disorder that often leads to liver fibrosis, a condition with limited therapy options. Adiponectin is an adipocytokine that regulates glucose and lipid metabolism via binding to its receptors AdipoR1 and AdipoR2, and AdipoRs signaling is reported to enhance fatty acid oxidation and glucose uptake. Here, we synthesize and report an adiponectin-based agonist JT003, which potently improves insulin resistance in high fat diet induced NASH mice and suppresses hepatic stellate cells (HSCs) activation in CCl₄ induced liver fibrosis. Mechanistic studies indicate that JT003 simultaneously stimulates AdipoR1- and AdipoR2- mediated signaling pathways as well as the PI3K-Akt pathway. Moreover, JT003 treatment significantly improves ER-mitochondrial axis function, which contributes to the reduced HSCs activation. Thus, the AdipoR1/AdipoR2 dual agonist improves both NASH and fibrosis in mice models, which provides the pharmacological and biological foundation for developing AdipoRs-based therapeutic agents on liver fibrosis.

Nonalcoholic steatohepatitis (NASH) and associated liver fibrosis have limited therapy options. Here the authors report a novel adiponectin-based dual agonist for adiponectin receptors 1 and 2 with a longer half-life, and show that it ameliorates NASH and liver fibrosis in mouse models.

Advances in understanding the role of adiponectin in renal fibrosis

Renal fibrosis is characterized by the proliferation of renal intrinsic cells, activation of renal interstitial fibroblasts and deposition of extracellular matrix (ECM), processes that lead to the progressive loss of renal function. Renal fibrosis is characterized by the proliferation of renal intrinsic cells, activation of renal interstitial fibroblasts, and septal fibrosis is recognized as a marker for the progression of chronic kidney disease, a condition that is associated with high morbidity and mortality and is a significant public health burden. Despite extensive studies, there are no effective treatments for renal fibrosis. Adiponectin (APN) is a protein mainly produced by adipocytes that has anti-inflammatory and anti-atherosclerotic effects, improves insulin resistance and provides other salutary effects. Recent studies found that APN can inhibit ECM deposition by inhibiting inflammation and oxidative stress, and by regulating the TGF-β, AMPK, MCP-1 and other signalling pathways. Many recent studies have examined the roles of these pathways in the pathogenesis of renal fibrosis. In this article, we review the pathogenic mechanism of APN in renal fibrosis and provide a theoretical basis for delaying and blocking renal fibrosis by alteration of APN activity.

Adipocytes protect fibroblasts from radiation-induced damage by adiponectin secretion

Prostate and colon cancers are among the most common cancers diagnosed annually, and both often require treatment with radiation therapy. Advancement in radiation delivery techniques has led to highly accurate targeting of tumor and sparing of normal tissue; however, in the pelvic region it is anatomically difficult to avoid off-target radiation exposure to other organs. Chronically the effects of normal urogenital tissue exposure can lead to urinary frequency, urinary incontinence, proctitis, and erectile dysfunction. Most of these symptoms are caused by radiation-induced fibrosis and reduce the quality of life for cancer survivors. We have observed in animal models that the severity of radiation-induced fibrosis in normal tissue correlates to damaged fat reservoirs in the pelvic region. We hypothesize that adipocytes may secrete a factor that prevents the induction of radiation-associated fibrosis in normal tissues. In these studies we show that the adipokine, adiponectin, is secreted by primary mouse adipocytes and protects fibroblasts from radiation-induced cell death, myofibroblast formation, and senescence. Further, we demonstrated that adiponectin does not protect colorectal or prostate cancer cells from radiation-induced death. Thus, we propose that adiponectin, or its downstream pathway, would provide a novel target for adjuvant therapy when treating pelvic cancers with radiation therapy.

Targeting perivascular and epicardial adipose tissue inflammation: therapeutic opportunities for cardiovascular disease

Major shifts in human lifestyle and dietary habits toward sedentary behavior and refined food intake triggered steep increase in the incidence of metabolic disorders including obesity and Type 2 diabetes. Patients with metabolic disease are at a high risk of cardiovascular complications ranging from microvascular dysfunction to cardiometabolic syndromes including heart failure. Despite significant advances in the standards of care for obese and diabetic patients, current therapeutic approaches are not always successful in averting the accompanying cardiovascular deterioration. There is a strong relationship between adipose inflammation seen in metabolic disorders and detrimental changes in cardiovascular structure and function. The particular importance of epicardial and perivascular adipose pools emerged as main modulators of the physiology or pathology of heart and blood vessels. Here, we review the peculiarities of these two fat depots in terms of their origin, function, and pathological changes during metabolic deterioration. We highlight the rationale for pharmacological targeting of the perivascular and epicardial adipose tissue or associated signaling pathways as potential disease modifying approaches in cardiometabolic syndromes.

Adiponectin-Based Peptide (ADP355) Inhibits Transforming Growth Factor-β1-Induced Fibrosis in Keloids

Keloids, benign cutaneous overgrowths of dermal fibroblasts, are caused by pathologic scarring of wounds during healing. Current surgical and therapeutic modalities are unsatisfactory. Although adiponectin has shown an antifibrotic effect, its large size and insolubility limit its potential use in keloid treatment. We investigated the effect of a smaller and more stable adiponectin-based peptide (ADP355) on transforming growth factor β1 (TGF-β1)-induced fibrosis in a primary culture of keloid fibroblasts prepared from clinically obtained keloid samples. Xenograft of keloid tissues on athymic nude mice was used to investigate the effect of intralesional injection of ADP355. ADP355 significantly attenuated the TGF-β1-induced expression of procollagen type 1 in keloid fibroblasts (p < 0.05). Moreover, it inhibited the TGF-β1-induced phosphorylation of SMAD3 and ERK, while amplifying the phosphorylation of AMP-activated protein kinase (p < 0.05). Knockdown of adiponectin receptor 1 reversed the attenuation of procollagen expression in ADP355-treated TGF-β1-induced fibrosis (p < 0.05). ADP355 also significantly reduced the gross weight and procollagen expression of keloid tissues in xenograft mice compared to control animals. These results demonstrate the therapeutic potential of the adiponectin peptide ADP355 for keloids.

Adiponectin inhibits vascular smooth muscle cell calcification induced by beta-glycerophosphate through JAK2/STAT3 signaling pathway

Vascular calcification is a common problem in the elderly with diabetes, heart failure and end-stage renal disease. The differentiation of vascular smooth muscle cells (VSMCs) into osteoblasts is the main feature, but the exact mechanism remains unclear. It is not clear whether adiponectin (APN) affects osteogenic differentiation of VSMCs. This study aims to explore the effect of APN on vascular calcification by using a cell model induced by beta-glycerophosphate (beta-GP). VSMCs were isolated and treated with beta-GP and APN in this study. The alkaline phosphatase (ALP) activity and expression levels of Runx2, BMP-2, collagen type I and osteocalcin were determined. The expression levels of STAT3 and p-STAT3 in nucleus and cytoplasm of VSMCs were analyzed. The results showed that APN significantly inhibited the expression of ALP, Runx2, BMP-2, collagen I, osteocalcin and the formation of the mineralized matrix in VSMCs induced by beta-GP. APN reduces the osteogenic differentiation of VSMCs induced by beta-GP and down-regulates the expression of the osteogenic transcription factor osterix by inhibiting STATS3 phosphorylation and nuclear transport. APN may be one of the potential candidates for clinical treatment of vascular calcification.

Angiotensin-(1-7), Adipokines and Inflammation

Nowadays the adipose tissue is recognized as one of the most critical endocrine organs releasing many adipokines that regulate metabolism, inflammation and body homeostasis. There are several described adipokines, including the renin-angiotensin system (RAS) components that are especially activated in some diseases with increased production of angiotensin II and several pro-inflammatory hormones. On the other hand, RAS also expresses angiotensin-(1-7), which is now recognized as the main peptide on counteracting Ang II effects. New studies have shown that increased activation of ACE2/Ang-(1-7)/MasR arm can revert and prevent local and systemic dysfunctions improving lipid profile and insulin resistance by modulating insulin actions, and reducing inflammation. In this context, the present review shows the interaction and relevance of Ang-(1-7) effects on regulating adipokines, and as one adipokine itself, modulating body homeostasis, with emphasis on its anti-inflammatory properties, especially in the context of metabolic disorders with focus on obesity and type 2 diabetes mellitus pandemic.

The Role of Phospho-c-Jun N-Terminal Kinase Expression on hepatocyte Necrosis and Autophagy in the Cholestatic Liver

BACKGROUND

Clinically, liver fibrosis and cholestasis are two major disease entities, ultimately leading to hepatic failure. Although autophagy plays a substantial role in the pathogenesis of these diseases, its precise mechanism has not been determined yet.

MATERIALS AND METHODS

Mouse models of liver fibrosis or cholestasis were obtained after the serial administration of thioacetamide (TAA) or surgical bile duct ligation (BDL), respectively. Then, after obtaining liver specimens at specific time points, we compared the expression of makers related to apoptosis (cleaved caspases), inflammation (CD68), necrosis (high-mobility group box 1), phospho-c-Jun N-terminal kinase (p-JNK), and autophagy (microtubule-associated protein light chain 3B and p62) in the fibrotic or cholestatic mouse livers, by polymerase chain reaction, Western blot analysis, immunohistochemistry, and immunofluorescence.

RESULTS

Although cholestatic livers exhibited the tendency of progressively increasing the expression of most apoptosis-related markers (cleaved caspases), it was not prominent when it was compared with the tendency found in the livers of TAA-treated mice. Contrastingly, the necrosis-related factor (high-mobility group box 1) was significantly increased in the livers of BDL mice over time, reaching their peak values on day 7 after BDL. In addition, the inflammation-related factor (CD68) was highly expressed in BDL mice compared with TAA-treated mice over time. Autophagy marker studies indicated that autophagy was upregulated in fibrotic livers, whereas it was downregulated in cholestatic livers. We also observed mild to moderate activation of p-JNK in the livers of TAA-treated mice, whereas significantly higher p-JNK activation was detected in the livers of BDL mice.

CONCLUSIONS

Unlike TAA-treated mice, BDL mice exhibited higher expression of the markers related with inflammation and necrosis, especially including p-JNK, while maintaining low levels of autophagic process. Therefore, obstructive cholestasis is characterized by higher p-JNK activation, which could be related with marked necrotic cell death resulting from extensive inflammation and little chance of compensatory autophagy.

Preclinical insights into cholangiopathies: disease modeling and emerging therapeutic targets

INTRODUCTION

The common predominant clinical features of cholangiopathies such as primary sclerosing cholangitis (PSC), primary biliary cholangitis (PBC), and biliary atresia (BA) are biliary damage/senescence and liver fibrosis. Curative therapies are lacking, and liver transplantation is the only option. An understanding of the mechanisms and pathogenesis is needed to develop novel therapies. Previous studies have developed various disease-based research models and have identified candidate therapeutic targets. Areas covered: This review summarizes recent studies performed in preclinical models of cholangiopathies and the current understanding of the pathophysiology representing potential targets for novel therapies. A literature search was conducted in PubMed using the combination of the searched term 'cholangiopathies' with one or two keywords including 'model', 'cholangiocyte', 'animal', or 'fibrosis'. Papers published within five years were obtained. Expert opinion: Access to appropriate research models is a key challenge in cholangiopathy research; establishing more appropriate models for PBC is an important goal. Several preclinical studies have demonstrated promising results and have led to novel therapeutic approaches, especially for PSC. Further studies on the pathophysiology of PBC and BA are necessary to identify candidate targets. Innovative therapeutic approaches such as stem cell transplantation have been introduced, and those therapies could be applied to PSC, PBC, and BA.

Potential Adiponectin Receptor Response Modifier Therapeutics

Many human diseases may benefit from adiponectin replacement therapy, but due to pharmacological disadvantages of the intact protein, druggable options focus on peptidic, and small molecule agonists of the adiponectin receptor. Peptide-based adiponectin replacement drug leads are derived from, or resemble, the active site of globular adiponectin. ADP355, the first-in-class such peptide, exhibits low nanomolar cellular activities, and clinically acceptable efficacies in a series of fibrotic and inflammation-derived diseases. The advantage of small molecule therapies, spearheaded by AdipoRon, is oral availability and extension of utility to a series of metabolic conditions. It is exactly the difficulties in the reliability and readout of the in vitro measures and the wealth of in vivo models that make comparison of the various drug classes complicated, if not impossible. While only a fewer number of maladies could take advantage of adiponectin receptor antagonists, the limited number of these available can be very useful tools in target validation studies. Alternative approaches to direct adiponectin signaling control use upstream adiponectin production inducing therapies but currently these offer relatively limited success compared to direct receptor agonists.

Activating Adiponectin Signaling with Exogenous AdipoRon Reduces Myelin Lipid Accumulation and Suppresses Macrophage Recruitment after Spinal Cord Injury

Myelin-laden macrophages (mye-MΦ), resulting primarily from internalization of myelin debris by infiltrating bone marrow-derived macrophages in spinal cord injury (SCI), trigger inflammatory responses that largely contribute to secondary injury. Adiponectin, which is secreted from adipose tissue, is an important hormone that modulates macrophage inflammation. In the present study, we examined the role of adiponectin on macrophage-mediated neuroinflammation after SCI. We found that in vitro activation of adiponectin receptors (AdipoRs) by their agonist AdipoRon suppressed myelin lipid accumulation in mye-MΦ through APPL1/PPARγ/LXRα/ABCA1-mediated lipid efflux, subsequently inhibiting inflammation and restoring normal function to mye-MΦ. In vivo data further confirmed that intravenous administration of AdipoRon after SCI dampened recruitment of macrophages and reduced myelin lipid accumulation. Accordingly, AdipoRon treatment ameliorated post-SCI tissue damage and astrogliosis, resulting in improved motor function. Although there was no significant pathological exacerbation in adiponectin-null mice subjected to SCI, our work reveals a functional link between adiponectin and hematogenous macrophages in the context of SCI, suggesting that activation of adiponectin signaling is a promising therapeutic approach to mitigate mye-MΦ-mediated neuroinflammation in neurological disorders involving demyelination.

miR-876-3p regulates glucose homeostasis and insulin sensitivity by targeting adiponectin

miRNA has been known to regulate diverse cellular and molecular functions. In the earlier study, we have reported that adipocytes differentiated from human mesenchymal stem cells (hMSC) on 72-h chronic insulin (CI) treatment exhibit insulin resistance (IR). Present study has further explored above model to investigate the role of early expressed miRNAs within human adipocytes to modulate differential adipokine expression as observed during IR. Our results highlight that miR-876-3p regulate glucose homeostasis and its dysregulation leads to IR. We found that miR-876-3p level is a critical determinant of adiponectin expression by virtue of its target within adiponectin 3′UTR. Regulatory effect of miR-876-3p impacts crosstalk between adiponectin and insulin signaling. Rosiglitazone treatment in CI-induced IR adipocytes drastically reduced miR-876-3p expression and increased adiponectin level. In line with this, lentiviral-mediated inhibition of miR-876-3p expression ameliorated CI and high-fat diet (HFD)-induced IR in adipocytes differentiated from hMSC and C57BL/6 mice, respectively. Our findings thus suggest that modulating miR-876-3p expression could provide novel opportunities for therapeutic intervention of obesity-associated metabolic syndrome.

A collagen domain-derived short adiponectin peptide activates APPL1 and AMPK signaling pathways and improves glucose and fatty acid metabolisms

Adiponectin is a fat tissue-derived adipokine with beneficial effects against diabetes, cardiovascular diseases, and cancer. Accordingly, adiponectin-mimetic molecules possess significant pharmacological potential. Oligomeric states of adiponectin appear to determine its biological activity. We identified a highly conserved, 13-residue segment (ADP-1) from adiponectin's collagen domain, which comprises GXXG motifs and has one asparagine and two histidine residues that assist in oligomeric protein assembly. We therefore hypothesized that ADP-1 promotes oligomeric assembly and thereby mediates potential metabolic effects. We observed here that ADP-1 is stable in human serum and oligomerizes in aqueous environments. We also found that ADP-1 activates AMP-activated protein kinase (AMPK) in an adaptor protein, phosphotyrosine interacting with PH domain and leucine zipper 1 (APPL1)-dependent pathway and stimulates glucose uptake in rat skeletal muscle cells (L6 myotubes). ADP-1-induced glucose transport coincided with ADP-1-induced biosynthesis of glucose transporter 4 and its translocation to the plasma membrane. ADP-1 induced an interaction between APPL1 and the small GTPase Rab5, resulting in AMPK phosphorylation, in turn leading to phosphorylation of p38 mitogen-activated protein kinase (MAPK), acetyl-CoA carboxylase, and peroxisome proliferator-activated receptor α. Similar to adiponectin, ADP-1 increased the expression of the adiponectin receptor 1 (AdipoR1) gene. Of note, ADP-1 decreased blood glucose levels and enhanced insulin production in pancreatic β cells in db/db mice. Further, ADP-1 beneficially affected lipid metabolism by enhancing lipid globule formation in mouse 3T3-L1 adipocytes. To our knowledge, this is the first report on identification of a short peptide from adiponectin with positive effects on glucose or fatty acid metabolism.

Adiponectin Attenuates Oxygen-Glucose Deprivation-Induced Mitochondrial Oxidative Injury and Apoptosis in Hippocampal HT22 Cells via the JAK2/STAT3 Pathway

Ischemic stroke is among the leading causes of morbidity and mortality worldwide. Improving the tolerance of neurons to ischemia and reperfusion injury could be a feasible strategy against ischemia. Adiponectin (APN) is a major adipokine that regulates glucose and lipid metabolism and plays an important role in the protection of the cerebral nervous system. We aimed to investigate the effects of APN on oxygen and glucose deprivation (OGD)-induced neuronal injury in hippocampal neuronal HT22 cells. APN displayed neuroprotective effects against OGD, evidenced by increased cell viability and decreased lactate dehydrogenase release and apoptotic rate. Additionally, APN also maintained mitochondrial ultrastructure and transmembrane potential, attenuated reactive oxygen species and malondialdehyde, and increased superoxide dismutase and glutathione peroxidase activity. Moreover, APN promoted Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) phosphorylation, enhanced STAT3 nuclear translocation, increased the Bcl-2/Bax ratio, and decreased cleaved caspase-3. The aforementioned APN-induced effects were almost reversed by a JAK2 inhibitor, AG490. APN may attenuate OGD-induced hippocampal HT22 neuronal impairment by protecting cells against mitochondrial oxidative stress and apoptosis, mediated by JAK2/STAT3 signaling.

Arctigenin protects against liver injury from acute hepatitis by suppressing immune cells in mice

As a phenylpropanoid and dibenzylbutyrolactone lignan present in medical plants, such as those used in traditional Chinese herbal medicine, including Arctium lappa (Niubang), arctigenin exhibits antimicrobial, anti-inflammatory, and anticancer activities. In this study, we investigated the protective role of arctigenin in Concanavalin A (ConA)-induced acute hepatitis in mice. Arctigenin remarkably reduced the congestion and necroinflammation of livers, and improved hepatic function (ALT and AST) in ConA-induced acute hepatitis in vivo. The infiltration of CD4 T, NKT and macrophages into the livers was found to be reduced with arctigenin treatment. Arctigenin suppressed ConA-induced T lymphocyte proliferations that might have resulted from enhanced IL-10 production by macrophages and CD4 T cells. These results suggested that arctigenin could be a powerful drug candidate for acute hepatitis through immune suppression.

Plumbagin protects liver against fulminant hepatic failure and chronic liver fibrosis via inhibiting inflammation and collagen production

Plumbagin is a quinonoid constituent extracted from Plumbago genus, and it exhibits diverse pharmacological effects. This study thoroughly investigated the effects of plumbagin on thioacetamide-induced acute and chronic liver injury. Results shown that plumbagin increased survival rate, reduced liver congestion and inflammation, and decreased macrophages and neutrophils in the fulminant hepatic failure model, and remarkably diminished liver fibrosis and inflammation in the chronic liver injury model. Furthermore, plumbagin significantly suppress the HSCs/myofibroblasts activation by reduced expression of markers α-SMA and COL-1/3, and reduced macrophage in liver. In the in vitro study, plumbagin induced apoptosis and suppressed the proliferation of LX-2 cells (human HSCs). Plumbagin treatment increased AMPK phosphorylation and attenuated NF-κB, STAT3, and Akt/mTOR signals in LX-2 cells, while SMAD2 phosphorylation was not changed. Noticeably, plumbagin promoted AMPK binding to p300 which is a cofactor of SMAD complex, this may further competitively decreases the p300/SMAD complex initiated transcription of COL-1/3 and α-SMA. Additionally, plumbagin hampered inflammation related NF-κB signal in RAW 264.7 cells. In conclusion, these findings indicate that plumbagin may be a powerful drug candidate to protect the liver from acute and chronic damage by inhibiting inflammation and collagen production.

Mesenchymal stem cells reverse high‑fat diet‑induced non‑alcoholic fatty liver disease through suppression of CD4+ T lymphocytes in mice

Although the multipotency of mesenchymal stem cells (MSCs) makes them an attractive choice for clinical applications, immune modulation is an important factor affecting MSC transplantation. At present, the effect of treatment with MSCs on non‑alcoholic fatty liver disease (NAFLD) has received little attention. In the present study, a compact bone‑derived method was used to isolate mouse MSCs (mMSCs) and a high‑fat diet was used to establish a mouse model of NAFLD. Immunophenotypic features of mMSCs were analyzed using flow cytometry. Paraffin sections were stained with hematoxylin and eosin to assess inflammation and steatosis, and with picrosirius red to assess fibrosis. Spleen leukocytes were analyzed by flow cytometry. The results demonstrated that compact bone‑derived MSC transplantation decreased high‑fat diet‑induced weight gain, expansion of subcutaneous adipose tissue, steatosis, lobular inflammation and liver fibrogenesis. Flow cytometry analysis of spleen leukocytes demonstrated that compact bone‑derived MSC transplantation suppressed the proliferation of cluster of differentiation (CD) 4+ T lymphocytes in the spleen, which had been induced by the high‑fat diet. In conclusion, compact bone‑derived MSCs may exhibit clinical value in the treatment of NAFLD through their capacity to suppress the activation of CD4+ T cells.

Hepatic stellate cells as key target in liver fibrosis

Progressive liver fibrosis, induced by chronic viral and metabolic disorders, leads to more than one million deaths annually via development of cirrhosis, although no antifibrotic therapy has been approved to date. Transdifferentiation (or "activation") of hepatic stellate cells is the major cellular source of matrix protein-secreting myofibroblasts, the major driver of liver fibrogenesis. Paracrine signals from injured epithelial cells, fibrotic tissue microenvironment, immune and systemic metabolic dysregulation, enteric dysbiosis, and hepatitis viral products can directly or indirectly induce stellate cell activation. Dysregulated intracellular signaling, epigenetic changes, and cellular stress response represent candidate targets to deactivate stellate cells by inducing reversion to inactivated state, cellular senescence, apoptosis, and/or clearance by immune cells. Cell type- and target-specific pharmacological intervention to therapeutically induce the deactivation will enable more effective and less toxic precision antifibrotic therapies.

The emerging role of AMP-activated protein kinase in cholestatic liver diseases

AMP-activated protein kinase (AMPK), recognized as an energy sensor with three heterotrimeric subunits (α, β and γ), not only maintains basal intracellular adenosine triphosphate levels but also regulates energy-intensive pathological responses, such as neurodegenerative and metabolic diseases, through multiple signaling pathways. Recent studies open a new direction for AMPK research and demonstrate that AMPK is a critical player in the pathogenesis of cholestatic liver injury and plays paradoxical roles in the regulation of different pathological processes, including the disruption of bile acid homeostasis and the regulation of hepatic polarity, inflammation and fibrosis. In the present review, we summarize recent findings that implicate AMPK-mediated signaling pathways in the pathogenesis of cholestatic liver injury. These findings provide novel insight regarding the potential use of AMPK as a therapeutic target for the treatment of cholestatic liver injury.

Activation of Adiponectin Receptor Regulates Proprotein Convertase Subtilisin/Kexin Type 9 Expression and Inhibits Lesions in ApoE-Deficient Mice

Objective—

The reduced adiponectin levels are associated with atherosclerosis. Adiponectin exerts its functions by activating adiponectin receptor (AdipoR). Proprotein convertase subtilisin kexin type 9 (PCSK9) degrades LDLR protein (low-density lipoprotein receptor) to increase serum LDL-cholesterol levels. PCSK9 expression can be regulated by PPARγ (peroxisome proliferator–activated receptor γ) or SREBP2 (sterol regulatory element-binding protein 2). The effects of AdipoR agonists on PCSK9 and LDLR expression, serum lipid profiles, and atherosclerosis remain unknown.

Approach and Results—

At cellular levels, AdipoR agonists (ADP355 and AdipoRon) induced PCSK9 transcription/expression that solely depended on activation of PPAR-responsive element in the PCSK9 promoter. AdipoR agonists induced PPARγ expression; thus, the AdipoR agonist-activated PCSK9 expression/production was impaired in PPARγ deficient hepatocytes. Meanwhile, AdipoR agonists transcriptionally activated LDLR expression by activating SRE in the LDLR promoter. Moreover, AMP-activated protein kinase α (AMPKα) was involved in AdipoR agonist-activated PCSK9 expression. In wild-type mice, ADP355 increased PCSK9 and LDLR expression and serum PCSK9 levels, which was associated with activation of PPARγ, AMPKα and SREBP2 and reduction of LDL-cholesterol levels. In contrast, ADP355 reduced PCSK9 expression/secretion in apoE-deficient (apoE −/− ) mice, but it still activated hepatic LDLR, PPARγ, AMPKα, and SREBP2. More importantly, ADP355 inhibited lesions in en face aortas and sinus lesions in aortic root in apoE −/− mice with amelioration of lipid profiles.

Conclusions—

Our study demonstrates that AdipoR activation by agonists regulated PCSK9 expression differently in wild-type and apoE −/− mice. However, ADP355 activated hepatic LDLR expression and ameliorated lipid metabolism in both types of mice and inhibited atherosclerosis in apoE −/− mice.

Adipokines in Liver Cirrhosis

Liver fibrosis can progress to cirrhosis, which is considered a serious disease. The Child-Pugh score and the model of end-stage liver disease score have been established to assess residual liver function in patients with liver cirrhosis. The development of portal hypertension contributes to ascites, variceal bleeding and further complications in these patients. A transjugular intrahepatic portosystemic shunt (TIPS) is used to lower portal pressure, which represents a major improvement in the treatment of patients. Adipokines are proteins released from adipose tissue and modulate hepatic fibrogenesis. These proteins affect various biological processes that are involved in liver function, including angiogenesis, vasodilation, inflammation and deposition of extracellular matrix proteins. The best studied adipokines are adiponectin and leptin. Adiponectin protects against hepatic inflammation and fibrogenesis, and leptin functions as a profibrogenic factor. These and other adipokines are supposed to modulate disease severity in patients with liver cirrhosis. Consequently, circulating levels of these proteins have been analyzed to identify associations with parameters of hepatic function, portal hypertension and its associated complications in patients with liver cirrhosis. This review article briefly addresses the role of adipokines in hepatitis and liver fibrosis. Here, studies having analyzed these proteins in systemic blood in cirrhotic patients are listed to identify adipokines that are comparably changed in the different cohorts of patients with liver cirrhosis. Some studies measured these proteins in systemic, hepatic and portal vein blood or after TIPS to specify the tissues contributing to circulating levels of these proteins and the effect of portal hypertension, respectively.

Adiponectin modulates oxidative stress-induced mitophagy and protects C2C12 myoblasts against apoptosis

Adiponectin (APN), also known as apM1, Acrp30, GBP28 and adipoQ, is a circulating hormone that is predominantly produced by adipose tissue. Many pharmacological studies have demonstrated that this protein possesses potent anti-diabetic, anti-atherogenic and anti-inflammatory properties. Although several studies have demonstrated the antioxidative activity of this protein, the regulatory mechanisms have not yet been defined in skeletal muscles. The aim of the present study was to examine the cytoprotective effects of APN against damage induced by oxidative stress in mouse-derived C2C12 myoblasts. APN attenuated H₂O₂-induced growth inhibition and exhibited scavenging activity against intracellular reactive oxygen species that were induced by H₂O₂. Furthermore, treating C2C12 cells with APN significantly induced heme oxygenase-1 (HO-1) and nuclear factor-erythroid 2 related factor 2 (Nrf2). APN also suppressed H₂O₂-induced mitophagy and partially inhibited the colocalization of mitochondria with autophagosomes/lysosomes, correlating with the expression of Pink1 and Parkin and mtDNA. Moreover, APN protected C2C12 myoblasts against oxidative stress-induced apoptosis. Furthermore, APN significantly reduced the mRNA and protein expression levels of Bax. These data suggest that APN has a moderate regulatory role in oxidative stress-induced mitophagy and suppresses apoptosis. These findings demonstrate the antioxidant potential of APN in oxidative stress-associated skeletal muscle diseases.

A potent peptide as adiponectin receptor 1 agonist to against fibrosis

Fibrotic diseases have become a major cause of death in the developed world. AdipoR1 agonists are potent inhibitors of fibrotic responses. Here, we focused on the in silico identification of novel AdipoR1 peptide agonists. A homology model was constructed to predict the 3D structure of AdipoR1. By docking to known active peptides, the putative active site of the model was further explored. A virtual screening study was then carried out with a set of manually designed peptides using molecular docking. Peptides with high docking scores were then evaluated for their anti-fibrotic properties. The data indicated that the novel peptide Pep70 significantly inhibited the proliferation of hepatic stellate cells (HSC) and NIH-3T3 cells (18.33% and 27.80%) and resulted in favouring cell-cycle arrest through increasing the accumulation of cells in the G0/G1 phase by 17.08% and 15.86%, thereby reducing the cell population in the G2/M phase by 11.25% and 15.95%, respectively. Additionally, Pep70 exhibited the most marked suppression on the expression of α-smooth muscle actin (α-SMA), collagen type I alpha1 (COL1A1) and TGF-β1. Therefore, the peptide Pep70 was ultimately identified as an inhibitor of fibrotic responses and as a potential AdipoR1 agonist.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) induces hepatic stellate cell (HSC) activation and liver fibrosis in C57BL6 mouse via activating Akt and NF-κB signaling pathways

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a widespread environmental pollutant that could induce serious toxic effects in both humans and rodents. Some studies suggested that TCDD exposure may facilitate the activation of hepatic stellate cells (HSCs) and liver injury. However, the underlying molecular mechanism by which environmental pollutants promote liver injury remains poorly understood. In the present study, we established an animal model of TCDD exposure by intraperitoneal injection of TCDD in male C57BL/6J mice. As revealed by Sirius red staining and hematoxylin-eosin (H&E) staining evaluation, we found that TCDD-exposed mice showed extensive disruption of liver architecture, including hepatocellular necrosis, inflammatory cell infiltration, and fibrosis. Furthermore, we showed that TCDD up-regulated the expression and secretion of the pro-inflammatory cytokines tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) in a dose-dependent manner in cultured HSCs. The effects of TCDD on cytokine secretion were very likely mediated by protein kinase B/Akt and Nuclear Factor kappa B (NF-κB) pathways, as indicated by the fact that TCDD markedly increased Akt phosphorylation and nuclear translocation of NF-κB p65 in HSCs. Furthermore, LY294002, an Akt inhibitor, significantly attenuated TCDD-triggered HSC activation through blocking Akt phosphorylation and NF-κB activation. These results indicate that HSCs are susceptible to the cytotoxic effects of TCDD and chronic TCDD exposure may contribute to liver fibrosis by activating HSC Akt and NF-κB signaling pathways.

Compact bone-derived mesenchymal stem cells attenuate nonalcoholic steatohepatitis in a mouse model by modulation of CD4 cells differentiation

Increasing evidence has accrued which indicates that mesenchymal stem cells (MSCs) have a potential clinical value in the treatment of certain diseases. Globally, nonalcoholic steatohepatitis (NASH) is a widespread disorder. In the present study, MSCs were isolated successfully from compact bone and a mouse model of NASH was established as achieved with use of a methionine-choline deficient (MCD) diet. Compact bone-derived MSCs transplantation reduced MCD diet-induced weight loss, hepatic lipid peroxidation, steatosis, ballooning, lobular inflammation and fibrogenesis. It was shown that MSCs treatment hampered MCD diet-induced proliferation of CD4⁺ IFN-γ⁺ and CD4⁺IL-6⁺ T spleen cells. In addition, CD4⁺IL-17⁺ lymphocytes that associated with anti-inflammation show little change in MCD as well as in MCD+MSCs splenocytes. We conclude that MSCs may have a potential clinical value upon NASH, through their capacity to suppress activation of CD4⁺ IFN-γ⁺ and CD4⁺IL-6⁺ lymphocytes.

Parthenolide ameliorates Concanavalin A-induced acute hepatitis in mice and modulates the macrophages to an anti-inflammatory state

Parthenolide, the principal sesquiterpene lactone present in medicinal plants such as feverfew, has anti-microbial, anti-inflammatory and anticancer activities. In the present study, we investigated the protective role of parthenolide against acute hepatitis in mice. Mice acute hepatitis were induced by Concanavalin A and treated by parthenolide in vivo. Results shown that parthenolide remarkably reduced the congestion and necroinflammation of the mice livers with Concanavalin A-induced acute hepatitis. Meanwhile, parthenolide treatment recover the liver function which indicated by decreased the serum alanine transaminase and alkaline phosphatase activities and promoted the expression of Ki67 in the livers of these mice. In addition, parthenolide administration suppressed the Concanavalin A-induced immune reaction, as indicated by the number of F4/80, CD49b and CD4 cells present in the liver. Furthermore, parthenolide also significantly reduced the expression of pro-inflammatory cytokines such as IFN-γ, TNF-α, IL-17A, IL-1β and IL-6 in lipopolysaccharide (LPS)-stimulated RAW264.7 cells in vitro. Moreover, parthenolide exposure decreased the phosphorylation of STAT3 and p38, and promoted the phosphorylation of p53 in RAW264.7 cells in vitro. In conclusion, parthenolide represents a drug candidate to protect the liver against Concanavalin A-induced acute hepatitis. The possible molecular mechanism involves the anti-inflammatory effects of parthenolide may by suppressing the STAT3/p38 signals and enhanced the p53 signals.