Jiawei guomin decoction regulates the degranulation of mast cells in atopic dermatitis mice via the HIS/PAR-2 pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Guomin decoction (GMD) is a traditional Chinese medicine commonly used in clinical practice. It has traditionally been used to treat all allergic diseases. Currently, Jiawei Guomin Decoction (JWGMD) is used to treat sensitive skin after initial therapy. Although it has a significant clinical therapeutic effect, the exact role of mast cell degranulation in treating atopic dermatitis (AD) is still unclear. AIM OF THE STUDY: GMD and JWGMD can both treat allergic diseases, while JWGMD focuses on skin allergies. This study aims to explore the potential effect of JWGMD on the degranulation of mast cells in an AD mouse model induced by 2,4-dinitrofluorobenzene (DNFB) and investigate the effectiveness of JWGMD in alleviating disease progression to further provide specific therapeutic targets for treating AD. MATERIALS AND METHODS: The scratching times and skin lesions of model mice induced by DNFB were observed, and skin tissues were collected for subsequent measurement. Histopathological changes in the back skin of mice were observed by haematoxylin eosin (H&E) staining, Toluidine blue staining was used to detect the degranulation of mouse skin mast cells, and the relationship between the expression of histamine (HIS), mast cell tryptase (MCT) and mast cell degranulation was analysed by enzyme-linked immunosorbent assay (ELISA). The expression of protease-activated receptor-2 (PAR-2), histamine 1 receptor (H1R), H2R, H4R and MCT proteins in AD mice was detected by Western blot (WB). Immunofluorescence assay (IFA) further confirmed the localization of PAR-2, H1R, H2R, H4R, and MCT proteins in the skin. Quantitative real-time PCR (qPCR) was used to determine PAR-2, H1R, H2R and H4R mRNA levels in skin lesions to further clarify the mechanism by which JWGMD amplifies mast cell degranulation in AD. In addition, a reliable ultrahigh-performance liquid chromatography-quadrupole electrostatic field orbitrap mass spectrometry (UPLC-QE-MS) nontargeted metabolomics analysis was performed to analyse the differences in metabolite abundance between GMD and JWGMD, and these results were used to identify the active components in JWGMD that may have antipruritic and anti-inflammatory properties and inhibit mast cell degranulation. RESULTS: After intermittent stimulation with DNFB, the skin lesions showed extensive desquamation, dryness, scabbing, skin thickening, and slight bleeding. Both treatments alleviated this phenomenon and reduced the number of scratches, with JWGMD being the most effective. JWGMD can significantly reduce inflammatory cell infiltration, oedema, and some capillary neogenesis in mice and reduce the degranulation of mast cells. The ELISA results showed that JWGMD can increase the levels of MCT and HIS proteins. The WB and IFA results demonstrated that JWGMD reduced the expression levels of PAR-2, H1R, H4R, and MCT proteins in skin lesions, with protein localization mainly in the epidermal layer, while H2R protein levels were increased and mainly localized in the dermis. In addition, JWGMD downregulates the mRNA expression of PAR-2, H1R, H2R, and H4R. Interestingly, through UPLC-QE-MS nontargeted metabolomic analysis, we detected the anti-inflammatory and antiallergy active substances in JWGMD, such as methyl eugenol, dictamnine and sinapine. CONCLUSIONS: JWGMD may alleviate itching through methyl syringol, dictamnine, sinapine and other substances, and its mechanism may be related to inhibiting the HIS/PAR-2 pathway in AD model mice and further regulating the self-amplification of mast cell degranulation. JWGMD is a potential drug for treating AD. Therefore, it deserves continuous attention and research.

Protease-Activated Receptor 2 (PAR2) Expressed in Sensory Neurons Contributes to Signs of Pain and Neuropathy in Paclitaxel Treated Mice.

Chemotherapy-induced peripheral neuropathy (CIPN) is a common, dose-limiting side effect of cancer therapy. Protease-activated receptor 2 (PAR2) is implicated in a variety of pathologies, including CIPN. In this study, we demonstrate the role of PAR2 expressed in sensory neurons in a paclitaxel (PTX)-induced model of CIPN in mice. PAR2 knockout/wildtype (WT) mice and mice with PAR2 ablated in sensory neurons were treated with PTX administered via intraperitoneal injection. In vivo behavioral studies were done in mice using von Frey filaments and the Mouse Grimace Scale. We then examined immunohistochemical staining of dorsal root ganglion (DRG) and hind paw skin samples from CIPN mice to measure satellite cell gliosis and intra-epidermal nerve fiber (IENF) density. The pharmacological reversal of CIPN pain was tested with the PAR2 antagonist C781. Mechanical allodynia caused by PTX treatment was alleviated in PAR2 knockout mice of both sexes. In the PAR2 sensory neuronal conditional knockout (cKO) mice, both mechanical allodynia and facial grimacing were attenuated in mice of both sexes. In the DRG of the PTX-treated PAR2 cKO mice, satellite glial cell activation was reduced compared to control mice. IENF density analysis of the skin showed that the PTX-treated control mice had a reduction in nerve fiber density while the PAR2 cKO mice had a comparable skin innervation as the vehicle-treated animals. Similar results were seen with satellite cell gliosis in the DRG, where gliosis induced by PTX was absent in PAR cKO mice. Finally, C781 was able to transiently reverse established PTX-evoked mechanical allodynia. PERSPECTIVE: Our work demonstrates that PAR2 expressed in sensory neurons plays a key role in PTX-induced mechanical allodynia, spontaneous pain, and signs of neuropathy, suggesting PAR2 as a possible therapeutic target in multiple aspects of PTX CIPN.

Biochanin-A has antidiabetic, antihyperlipidemic, antioxidant, and protective effects on diabetic nephropathy via suppression of TGF-ß1 and PAR-2 genes expression in kidney tissues of STZ-induced diabetic rats.

One of the major complications of diabetes is diabetic nephropathy, and often many patients suffer from diabetic nephropathy. That is why it is important to find the mechanisms that cause nephropathy and its treatment. This study was designed to examine the antidiabetic effects of biochanin A (BCA) and evaluate its effects on oxidative stress markers and the expression of transforming growth factor-ß1 (TGF-ß1) and protease-activated receptors-2 (PAR-2) genes in the kidney of type 1 diabetic rats. After induction of diabetes using streptozotocin (STZ), 55 mg/kg bw dose, rats were randomly divided into four groups with six rats in each group as follows: normal group: normal control receiving normal saline and a single dose of citrate buffer daily; diabetic control group: diabetic control receiving 0.5% dimethyl sulfoxide daily; diabetic+BCA (10 mg/kg) group: diabetic rats receiving biochanin A at a dose of 10 mg/kg bw daily; diabetic+BCA (15 mg/kg) group: diabetic rats receiving biochanin A at a dose of 15 mg/kg bw daily. TGF-ß1 and PAR-2 gene expression was assessed by real-time. Spectrophotometric methods were used to measure biochemical factors: fast blood glucose (FBG), urea, creatinine, albumin, lipids profiles malondialdehyde (MDA), and superoxide dismutase (SOD). The course of treatment in this study was 42 days. The results showed that in the diabetic control group, FBG, serum urea, creatinine, expression of TGF-ß1 and PAR-2 genes, and the levels of MDA in kidney tissue significantly increased and SOD activity in kidney tissue and serum albumin significantly decreased compared to the normal group (p < 0.001). The results showed that administration of biochanin A (10 and 15 mg/kg) after 42 days significantly reduced the expression of TGF-ß1 and PAR-2 genes and FBG, urea, creatinine in serum compared to the diabetic control group (p < 0.001), also significantly increased serum albumin compared to the diabetic control group (p < 0.001). The level of MDA and SOD activity in the tissues of diabetic rats that used biochanin A (10 and 15 mg/kg) was significantly reduced and increased, respectively, compared to the diabetic control group (p < 0.001). Also, the result showed that in the diabetic control group lipids profiles significantly is disturbed compared to the normal group (p < 0.001), the results also showed that biochanin A (10 and 15 mg/kg) administration could significantly improved the lipids profile compared to the control diabetic group (p < 0.001). It is noteworthy that it was found that the beneficial effects of the biochanin A were dose dependent. In conclusion, administration of biochanin A for 42 days has beneficial effect and improves diabetes and nephropathy in diabetic rats. So probably biochanin A can be used as an adjunct therapy in the treatment of diabetes.

Pain and chronic pancreatitis: is it the plumbing or the wiring?

Our progress in understanding the biology of chronic pancreatitis has been slow, particularly with respect to the pathogenesis of pain, the cardinal symptom. Although traditional theories have focused on anatomic changes, with interstitial and ductal hypertension as the main inciting factors for pain generation, subsequent studies have not confirmed a correlation between ductal pressure and the severity of pain or its relief after ductal decompression. Empirical approaches directed at anatomic causes are at best of marginal value. Although these phenomena are clearly associated with the disease, they are not likely the root cause of the pain. Instead, they probably are inciting factors on a background of neuronal sensitization induced by damage to the perineurium and subsequent exposure of the nerves to mediators and products of inflammation. In this review, we discuss the inherent limitations in our current therapies and try to identify new targets and approaches for the future, such as TRPV1, nerve growth factor-TrkA signaling, and perhaps protease activator receptor-2.

Physiology and pathophysiology of proteinase-activated receptors (PARs): PAR-2 as a potential therapeutic target.

PAR-2 is the second member of the family of proteinase-activated receptors activated by trypsin, tryptase, and several other serine proteinases. In order to evaluate the therapeutic potential for PAR-2, we have performed studies on PAR-2-mediated signal transduction and investigated the effects of PAR-2 gene deficiency in disease models. In addition to the G-protein-coupled receptor-mediated common signal transduction pathways, inositol 1,4,5-trisphosphate production and mobilization of Ca(2+), PAR-2 can also activate multiple kinase pathways, ERK, p38MAPK, JNK, and IKK, in a cell-type specific manner. The studies using PAR-2-gene-deficient mice highlighted critical roles of PAR-2 in progression of skin and joint inflammation. We also describe the development and evaluation of potent and metabolically stable PAR-2 agonists in multiple assay systems both in vitro and in vivo. The structure-activity relationship analysis indicated the improved potencies of furoylated peptides. Furthermore, the resistance of the furoylated peptide against aminopeptidase contributed to the highly potent and sustained effects of the peptide in vivo. These studies suggest the potential therapeutic importance of PAR-2 in inflammatory diseases. Also, the PAR-2-gene-deficient mice and the potent and metabolically stable agonists are shown to be useful tools for evaluating the potency of PAR-2 as a therapeutic target.

Proteinase-activated Receptor 2 (PAR2): a challenging new target for treatment of vascular diseases.

Proteinase-activated Receptor 2 (PAR2) is a potential target for the design of drug treatments for vascular diseases. Its unique mechanism of activation by serine proteinases, questions regarding the identities of endogenous agonists and its apparent multiple activities in the vasculature contribute to complex pharmacology. The progress of the pursuit to understand the function of PAR2 relies on the design of short specific peptides as selective agonists for PAR2 in receptor-selective cultured cell expression systems and is limited by the lack of any PAR2 antagonists. Fortunately, the utilization of transgenic PAR2-deficient mice enables the identification of the actions of selective PAR2-derived activating peptides attributed to activation solely of PAR2 in more physiologically complex systems. Of multiple pharmacological responses, PAR2-derived peptide agonists reduce vascular tone, and therefore increase blood flow, via nitric oxide-dependent and -independent paracrine actions of the endothelium upon the underlying vascular smooth muscle cells of blood vessels. PAR2-mediated endothelial-dependent relaxation and hyperpolarization of vascular smooth muscle in select arterial vascular beds via a nitric oxide/cyclooxygenases-independent mechanism suggests a strategy for correction of endothelium-based vascular dysfunction. Vascular tissues respond to progression of vascular diseases such as atherosclerosis or to injury with variable changes of PAR2 expression. With further research and drug development, PAR2 agonists and antagonists may become a basis for a new class of therapeutic agents for treatment of vascular diseases.