Jihua Fu

Important role of 5-hydroxytryptamine in glucocorticoid-induced insulin resistance in liver and intra-abdominal adipose tissue of rats.

Both glucocorticoids and 5‐hydroxytryptamine (5‐HT) have been shown to induce insulin resistance (IR) in hepatocytes and adipocytes. Here, we explore whether there is a correlation between them.

Influence of chronic stress on the compositions of hepatic cholesterol and triglyceride in male Wistar rats fed a high fat diet

Aim:  We determined the influence of chronic stress (CS) on the compositions of hepatic cholesterol and triglyceride (TG) in rats fed a high fat diet (HFD).

Long-term Stress with Hyperglucocorticoidemia-induced Hepatic Steatosis with VLDL Overproduction Is Dependent on both 5-HT2 Receptor and 5-HT Synthesis in Liver

Hepatic triglycerides production and adipose lipolysis are pivotal for long-term stress (LTS) or hyperglucocorticoidemia-induced insulin resistance. 5-hydroxytryptamine (5-HT) has been demonstrated to induce hepatic lipid metabolic abnormality by activating mammalian target of rapamycin (mTOR). In present study, we explored whether 5-HT is involved in LTS effects in liver using restraint stress-exposed rats and cultured primary rat hepatocytes and HepG2 cells. LTS with hyperglucocorticoidemia induced hepatic 5-HT synthetic increase with tryptophan hydroxylase 1 (Tph1) up-regulation, and 5-HT2 receptor (5-HT2R, including 5-HT2A, 2B receptor) up-regulation in liver and visceral adipose, as well as hepatic mTOR activation with triglycerides and VLDL overproduction with steatosis, and visceral adipose lipolytic increase with high blood free fatty acids (FFAs) level. 5-HT exposure exhibited LTS-like effects in both tissues, and both LTS and 5-HT effects could be abolished significantly by blocking 5-HT2R. In HepG2 cells dexamethasone or palmitate-induced mTOR activation with triglycerides and VLDL overproduction were accompanied by up-regulations of 5-HT synthesis and 5-HT2R, which were significantly abolished by gene silencing Tph1 or 5-HT2R and were almost fully abolished by co-silencing of both, especially on VLDL overproduction. Chemical inhibition of Tph1 or/and 5-HT2R in both hepatocytes exhibited similar abolishment with genetic inhibition on dexamethason-induced effects. 5-HT-stimulated effects in both hepatocytes were fully abolished by blocking 5-HT2R, while 5-HT itself also up-regulated 5-HT2R. In conclusion, up-regulated hepatic 5-HT synthesis and 5-HT2R induced by both glucocorticoid and FFAs are crucial for LTS-induced hepatic steatosis with VLDL overproduction, while 5-HT by acting on 5-HT2R mediates mTOR activation in liver.

Effective treatment with combination of peripheral 5‐hydroxytryptamine synthetic inhibitor and 5‐hydroxytryptamine 2 receptor antagonist on glucocorticoid‐induced whole‐body insulin resistance with hyperglycemia

Our previous study found that dexamethasone‐induced insulin resistance (IR) was involved in 5‐hydroxytryptamine (5‐HT) synthesis and 5‐hydroxytryptamine 2 receptor (5‐HT2R) in the periphery. The present study examined the effects of inhibitions of both peripheral 5‐HT synthesis and 5‐HT2R on dexamethasone‐induced IR.

Combination therapy of chitosan, gynostemma, and motherwort alleviates the progression of experimental rat chronic renal failure by inhibiting STAT1 activation

This study aimed to investigate the effect of single and combination therapy using chitosan (K), gynostemma (J), and motherwort (Y) on an experimental rat model of chronic renal failure (CRF) induced by adenine and the underlying mechanisms. CRF rats were treated with individual or combinational therapy with two or three of these agents. Biochemical indicators showed that the levels of blood urea nitrogen, creatinine and uric acid decreased and the levels of albumin and hemoglobin increased by single or combination therapy of these drugs. Drug treatment also decreased oxidative stress damage of renal tissues in CRF rats. Histopathological lesions were attenuated in each drug treatment group by various degrees. Additionally, drug treatment affected the expression of extracellular matrix (ECM) proteins including plasminogen activator inhibitor 1, collagen I, matrix metalloprotease-1, and tissue inhibitor of metalloproteinases 1. In particular, the combination therapy of K, J, and Y was superior to the respective monotherapy, which supported the prescription of KJY combination. We further studied the inhibitory effect of KJY on LPS-induced inflammation in RAW264.7 macrophages. The results showed that KJY inhibited LPS-induced secretion of inflammatory cytokines (Interferon-gamma, Interleukin-1 Beta, chemokine (C-X-C motif) ligand 10, cyclooxygenase-2 and Tumor necrosis factor-α in RAW264.7 macrophages. Combination therapy of KJY suppressed the protein expression of Cyclooxygenase-2 and inducible nitric oxide synthase in vivo and in vitro. Further study indicated that KJY inhibited STAT1 activation by down regulating p-STAT1 to exert anti-inflammatory effect and improve renal function in rats with chronic renal failure.

Crucial Roles of 5-HT and 5-HT 2 Receptor in Diabetes-Related Lipid Accumulation and Pro-Inflammatory Cytokine Generation in Hepatocytes

Background/Aims: Previously, we confirmed that liver-synthesized 5-HT rather than non-liver 5-HT, acting on the 5-HT2 receptor (5-HT2R), modulates lipid-induced excessive lipid synthesis (ELS). Here, we further revealed the effects of the hepatocellular 5-HT system in diabetes-related disorders. Methods: Studies were conducted in male ICR mice, human HepG2 cells, and primary mouse hepatocytes (PMHs) under gene or chemical inhibition of the 5-HT system, key lipid metabolism, and inflammation-related factors. Protein and messenger RNA expression and levels of the factors were determined via western blotting, reverse transcription PCR, and quantitative assay kits, respectively. Hepatic steatosis with inflammation and fibrosis, intracellular lipid droplet accumulation (LDA), and reactive oxygen species (ROS) location were determined via hematoxylin and eosin, Masson’s trichrome, Oil red O, and fluorescent-specific staining, respectively. Results: Palmitic acid induced the activation of the 5-HT system: the activation of 5-HT2R, primarily 5-HT2AR, in addition to upregulating monoamine oxidase A (MAO-A) expression and 5-HT synthesis, by activating the G protein/ phospholipase C pathway modulated PKCε activation, resulting in ELS with LDA; the activation of NF-κB, which mediates the generation of pro-inflammatory cytokines, was primarily due to ROS generation in the mitochondria induced by MAO-A–catalyzed 5-HT degradation, and secondarily due to the activation of PKCε. These effects of the 5-HT system were also detected in palmitic acid- or high glucose-treated PMHs and regulated multiple inflammatory signaling pathways. In diabetic mice, co-treatment with antagonists of both 5-HT synthesis and 5-HT2R significantly abolished hepatic steatosis, inflammation, and fibrosis as well as hyperglycemia and dyslipidemia. Conclusion: Activation of the hepatocellular 5-HT system plays a crucial role in inducing diabetes-related hepatic dysfunction and is a potential therapeutic target.

5-HT 2 receptor mediates high-fat diet-induced hepatic steatosis and very low density lipoprotein overproduction in rats.

BACKGROUND 5-HT has been shown to mediate abnormality of hepatic lipid metabolism through activation of mammalian target of rapamycin (mTOR). However, it is unclear whether 5-HT is directly involved in high-fat diet (HFD)-induced hepatic steatosis. MATERIALS AND METHODS Male rats were allocated into seven groups with control, either HFD feeding, 5-HT treatment, or HFD feeding and 5-HT treatment with or without sarpogrelate treatment, all of which were executed for 4 weeks. HepG2 cells were exposed to 5-HT or palmitic acid (PA) with or without rapamycin or Sar treatment. RESULTS Rats fed with HFD or exposed to 5-HT led to abnormalities with activated hepatic mTOR-S6K pathway, overproduction of hepatic triglycerides and VLDL with steatosis, and hyperlipidemia, which were exacerbated by a combination of HFD and 5-HT. Sarpogrelate significantly inhibited above abnormalities induced by HFD and 5-HT, alone or in a combination. Additionally, HFD caused up-regulation of 5-HT2 receptors (5-HT2R), including 5-HT2AR and 5-HT2BR, and 5-HT synthesis in the liver, without obvious influence on other 5-HT receptors gene expression. In HepG2 cells, both PA and 5-HT induced overproduction of triglycerides and VLDL with lipid droplets, and PA up-regulated 5-HT2AR and 5-HT2BR expression and 5-HT synthesis as well. Rapamycin fully abolished PA or 5-HT-induced mTOR activation, which was more effective than sarpogrelate. However, the inhibitory effects of rapamycin on PA or 5-HT-induced overproduction of triglycerides and VLDL were less than sarpogrelate. CONCLUSIONS Up-regulation of hepatic 5-HT2R and 5-HT synthesis by HFD is crucial for HFD-induced overproduction of hepatic triglycerides and VLDL with hyperlipidemia.

The Effects of Xiangqing Anodyne Spray on Treating Acute Soft-Tissue Injury Mainly Depend on Suppressing Activations of AKT and p38 Pathways

Objectives. In the present study we try to elucidate the mechanism of Xiangqing anodyne spray (XQAS) effects on acute soft-tissue injury (STI). Methods. Acute STI model was established by hammer blow in the rat hind leg muscle. Within 8 hours, instantly after modeling and per 2-hour interval repeated topical applications with or without XQAS, CP or IH ethanol extracts spray (CPS and IHS) were performed, respectively; muscle swelling rate and inflammation-related biochemical parameters, muscle histological observation, and mRNA and protein expression were then examined. Results. XQAS dose-dependently suppressed STI-caused muscle swelling, proinflammatory mediator productions, and oxidative stress as well as severe pathological changes in the injured muscle tissue. Moreover, CPS mainly by blocking p38 activation while IHS majorly by blocking AKT activation led to cytoplastic IκBα degradation with NF-κB p65 translocated into the nucleus. There are synergistic effects between CP and IH components in the XQAS on preventing from acute STI with suppressing IκBα degradation, NF-κB p65 translocation, and subsequent inflammation and oxidative stress-related abnormality. Conclusion. Marked effects of XQAS on treating acute STI are ascribed to strong anti-inflammatory and antioxidative actions with a reasonable combination of CP active components, blocking p38-NF-κB pathway activated, and IH active components, blocking AKT-NF-κB pathway activated.