am-630 and Fibrosis

In diabetic nephropathy agonism of CB2 receptors reduces albuminuria and podocyte loss; however, the role of CB2 receptors in obesity-related nephropathy is unknown. The aim of this study was to determine the role of CB2 receptors in a model of diet-induced obesity (DIO) and characterize the hallmark signs of renal damage in response to agonism (AM1241) and antagonism (AM630) of CB2 receptors.. Male Sprague Dawley rats were fed a high-fat diet (HFD: 40% digestible energy from lipids) for 10 weeks. In another cohort, after 9 weeks on a HFD, rats were injected daily with either 3 mg·kg(-1) AM1241, 0.3 mg·kg(-1) AM630 or saline for 6 weeks.. Ten weeks on a HFD significantly reduced renal expression of CB2 receptors and renal function. Treatment with AM1241 or AM630 did not reduce weight gain or food consumption in DIO. Despite this, AM1241 significantly reduced systolic BP, peri-renal adipose accumulation, plasma leptin, urinary protein, urinary albumin, urinary sodium excretion and the fibrotic markers TGF-β1, collagen IV and VEGF in kidney lysate. Treatment with AM630 of DIO rats significantly reduced creatinine clearance and increased glomerular area and kidney weight (gross and standardized for body weight). Diastolic BP, glucose tolerance, insulin sensitivity, plasma creatinine, plasma TGF-β1 and kidney expression of fibronectin and α-smooth muscle actin were not altered by either AM1241 or AM630 in DIO.. This study demonstrates that while agonism of CB2 receptors with AM1241 treatment for 6 weeks does not reduce weight gain in obese rats, it leads to improvements in obesity-related renal dysfunction.. This article is part of a themed section on Endocannabinoids. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v173.7/issuetoc.

Topics: Animals; Cannabinoids; Cytokines; Dietary Fats; Fibrosis; Indoles; Kidney; Kidney Glomerulus; Kidney Tubules; Male; Obesity; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB2; Weight Gain

Studies have shown that cannabinoid CB2 receptors are involved in wound repair, however, its physiological roles in fibrogenesis remain to be elucidated. In the present study, the capacity of cannabinoid CB2 receptors in the regulation of skin fibrogenesis during skin wound healing was investigated. To assess the function of cannabinoid CB2 receptors, skin excisional BALB/c mice were treated with either the cannabinoid CB2 receptor selective agonist, GP1a, or antagonist, AM630. Skin fibrosis was assessed by histological analysis and profibrotic cytokines were determined by immunohistochemistry, immunofluorescence staining, reverse transcription‑quantitative polymerase chain reaction and immunoblotting in these animals. GP1a decreased collagen deposition, reduced the levels of transforming growth factor (TGF)‑β1, TGF‑β receptor I (TβRI) and phosphorylated small mothers against decapentaplegic homolog 3 (P‑Smad3), but elevated the expression of its inhibitor, Smad7. By contrast, AM630 increased collagen deposition and the expression levels of TGF‑β1, TβRI and P‑Smad3. These results indicated that cannabinoid CB2 receptors modulate fibrogenesis and the TGF‑β/Smad profibrotic signaling pathway during skin wound repair in the mouse.

Topics: Actins; Animals; Blotting, Western; Collagen Type I; Collagen Type III; Cytokines; Disease Models, Animal; Fibrosis; Indoles; Male; Mice; Mice, Inbred BALB C; Microscopy, Fluorescence; Protein Serine-Threonine Kinases; Real-Time Polymerase Chain Reaction; Receptor, Cannabinoid, CB2; Receptor, Transforming Growth Factor-beta Type I; Receptors, Transforming Growth Factor beta; Skin Diseases; Smad3 Protein; Transforming Growth Factor beta1; Wound Healing

Previous studies showed that cannabinoid 2 (CB2) receptor is expressed in multiple effector cells during skin wound healing. Meanwhile, its functional involvement in inflammation, fibrosis, and cell proliferation in other organs and skin diseases implied CB2 receptor might also regulate skin wound healing. To verify this hypothesis, mice excisional wounds were created and treated with highly selective CB2 receptor agonist GP1a (1-(2,4-dichlorophenyl)-6-methyl- N-piperidin-1-yl-4H-indeno[1,2-c]pyrazole-3-carboxamide) and antagonist AM630 ([6-iodo-2- methyl-1-(2-morpholin-4-ylethyl)indol-3-yl]-(4-methoxyphenyl)methanone) respectively. The inflammatory infiltration, cytokine expression, fibrogenesis, and wound re-epithelialization were analyzed. After CB2 receptor activation, neutrophil and macrophage infiltrations were reduced, and expressions of monocyte chemotactic protein (MCP)-1, stromal cell-derived factor (SDF)-1, Interleukin (IL)-6, IL-1β, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β1 and vascular endothelial growth factor (VEGF)-A were decreased. Keratinocyte proliferation and migration were enhanced. Wound re-epithelialization was accelerated. Fibroblast accumulation and fibroblast-to-myofibroblast transformation were attenuated, and expression of pro-collagen I was decreased. Furthermore, HaCaT cells in vitro were treated with GP1a or AM630, which revealed that CB2 receptor activation promoted keratinocyte migration by inducing the epithelial to mesenchymal transition. These results, taken together, indicate that activating CB2 receptor could ameliorate wound healing by reducing inflammation, accelerating re-epithelialization, and attenuating scar formation. Thus, CB2 receptor agonist might be a novel perspective for skin wound therapy.

Topics: Animals; Cell Line; Collagen; Fibrosis; Gene Expression Regulation; Humans; Indenes; Indoles; Inflammation; Male; Mice; Pyrazoles; Re-Epithelialization; Receptor, Cannabinoid, CB2; Skin

The aim of the current study was to investigate the effects of cannabinoid receptor type 2 (CB2R) on the repair process of injured skeletal muscle, which could potentially lay solid foundations as a novel target for curing muscular fibrosis in future. A standardized rat model of skeletal muscle contusion was established, where rats were treated with the CB2R agonist JWH-133 or antagonist AM-630. The in vivo results revealed that CB2R activation with JWH-133 significantly diminished the fibrotic areas, down-regulated the mRNA levels of collagen type I/ІІІ and augmented the number of multinucleated regenerating myofibers in the injured zones. The reasons leading to the aforementioned results were directly attributable to decreased mRNA levels of TGF-β1, FN-EIIIA and α-SMA, reduced accumulation of myofibroblasts, and concomitantly increased mRNA levels of matrix metalloproteinase-1/2. However, we observed contrasting changes in rats treated with the CB2R antagonist AM-630. These results revealed multiple effects of CB2R in systematically inhibiting fibrotic formation and improving muscle regeneration, alongside its potential for clinical application in patients with skeletal muscle injuries and diseases.

Topics: Animals; Cannabinoids; Contusions; Fibrosis; Indoles; Male; Muscle, Skeletal; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB2; Regeneration; Wound Healing