Piperlonguminine attenuates renal fibrosis by inhibiting TRPC6.

ETHNOPHARMACOLOGICAL RELEVANCE: Liuwei Dihuang (LWDH) is a classic prescription that has been used to the treatment of "Kidney-Yin" deficiency syndrome for more than 1000 years in China. Recent studies have confirmed that LWDH can prevent the progression of renal fibrosis. Numerous studies have demonstrated the critical role that TRPC6 plays in the development of renal fibrosis. Due to the complex composition of LWDH and its remarkable therapeutic effect on renal fibrosis, it is possible to discover new active ingredients targeting TRPC6 for the treatment of renal fibrosis. AIM OF STUDY: This study aimed to identify selective TRPC6 inhibitors from LWDH and evaluate their therapeutical effects on renal fibrosis. MATERIALS AND METHODS: Computer-aided drug design was used to screen the biologically active ingredients of LWDH, and their affinities to human TRPC6 protein were detected by microcalorimetry. TRPC6, TRPC3, and TRPC7 over-expressed HEK293 cells were constructed, and the selective activities of the compounds on TRPC6 were determined by measuring [Ca2+]i in these cells. To establish an in vitro model of renal fibrosis, human renal proximal tubular epithelial HK-2 cells were stimulated with TGF-ß1. The therapeutic effects of LWDH compounds on renal fibrosis were then tested by detecting the related proteins. TRPC6 was knocked-down in HK-2 cells to investigate the effects of LWDH active ingredients on TRPC6. Finally, a unilateral ureteral obstruction model of renal fibrosis was established to test the therapeutic effect. RESULTS: From hundreds of LWDH ingredients, 64 active components with oral bioavailability ≥30% and drug-likeness index ≥0.18 were acquired. A total of 10 active components were obtained by molecular docking with TRPC6 protein. Among them, 4 components had an affinity with TRPC6. Piperlonguminine (PLG) had the most potent affinity with TRPC6 and blocking effect on TRPC6-mediated Ca2+ entry. A 100 µM of PLG showed no detectable inhibition on TRPC1, TRPC3, TRPC4, TRPC5, or TRPC7-mediated Ca2+ influx into cells. In vitro results indicated that PLG concentration-dependently inhibited the abnormally high expression of α-smooth muscle actin (α-SMA), collagen I, vimentin, and TRPC6 in TGF-ß1-induced HK-2 cells. Consistently, PLG also could not further inhibit TGF-ß1-induced expressions of these protein biomarkers in TRPC6 knocked-down HK-2 cells. In vivo, PLG dose-dependently reduced urinary protein, serum creatinine, and blood urea nitrogen levels in renal fibrosis mice and markedly alleviated fibrosis and the expressions of α-SMA, collagen I, vimentin, and TRPC6 in kidney tissues. CONCLUSION: Our results showed that PLG had anti-renal fibrosis effects by selectively inhibiting TRPC6. PLG might be a promising therapeutic agent for the treatment of renal fibrosis.

Analysis of the network pharmacology and the structure-activity relationship of glycyrrhizic acid and glycyrrhetinic acid.

Licorice, a herbal product derived from the root of Glycyrrhiza species, has been used as a sweetening agent and traditional herbal medicine for hundreds of years. Glycyrrhizic acid (GL) and glycyrrhetinic acid (GA) are the most important active ingredients in licorice. Both GL and GA have pharmacological effects against tumors, inflammation, viral infection, liver diseases, neurological diseases, and metabolic diseases. However, they also exhibit differences. KEGG analysis indicated that licorice is involved in neuroactive ligand‒receptor interactions, while 18ß-GA is mostly involved in arrhythmogenic right ventricular cardiomyopathy. In this article, we comprehensively review the therapeutic potential of GL and GA by focusing on their pharmacological effects and working mechanisms. We systemically examine the structure-activity relationship of GL, GA and their isomers. Based on the various pharmacological activities of GL, GA and their isomers, we propose further development of structural derivatives of GA after chemical structure modification, with less cytotoxicity but higher targeting specificity. More research is needed on the clinical applications of licorice and its active ingredients.

Local anaesthesia for surgical extraction of mandibular third molars: a systematic review and network meta-analysis.

OBJECTIVES: Pain management for the extraction of the mandibular third molar is a challenge as compelling evidence in comparative anaesthetics is currently lacking. MATERIALS AND METHODS: Thorough literature searches took place in PubMed, ScienceDirect, CENTRAL, Embase, Web of Science, CBM, and CNKI. Thirty-three trials were meta-analysed using a Bayesian statistical approach within the random-effects model. Grading of Recommendations Assessment, Development, and Evaluation was performed to determine the overall quality of evidence across all comparisons. RESULTS: In terms of success rate, an inferior alveolar nerve block (IANB) injection of 2% lidocaine with epinephrine was less effective than a combined injection of buccal infiltration (BI) and lingual infiltration (LI) with a 4% articaine (RR = 0.85 [0.75, 0.96], P = 0.611). According to visual analogue scale (VAS), 2% lidocaine-IANB with epinephrine caused higher VAS scores than 4% articaine-IANB with epinephrine (MD = 0.84 [0.28, 1.40], P = 0.057), whereas 0.5% levobupivacaine-IANB showed lower scores than 2% lidocaine-IANB (MD = - 1.62 [- 2.97, - 0.28], P = 0.045). Also, 2% lidocaine-IANB with epinephrine presented longer latency than both 4% articaine-IANB with epinephrine (MD = 39.44 [16.97, 61.90], P < 0.001) and 4% articaine-BI + LI with epinephrine (MD = 164.41 [16.23, 312.58], P < 0.001); 4% articaine-IANB with epinephrine produced shorter latency than 0.5% bupivacaine-IANB with epinephrine (MD = - 42.92 [- 70.28, - 15.56], P = 0.106); 0.75% ropivacaine-IANB caused shorter onset of action compared with 2% lidocaine-IANB (MD = - 40.88 [- 65.50, - 16.26], P < 0.001). In addition, 2% lidocaine-IANB with epinephrine produced significantly shorter duration than both 4% articaine-IANB with epinephrine (MD = - 47.33 [- 57.88, - 36.77], P = 0.265) and 2% mepivacaine-IANB with epinephrine (MD = - 10.01 [- 19.59, - 0.44], P = 0.769). The duration of action triggered by 4% articaine-IANB with epinephrine was shorter compared with 0.5% bupivacaine-IANB with epinephrine (MD = - 64.17 [- 74.65, - 53.69], P = 0.926). Both 0.5% levobupivacaine-IANB and 0.75% ropivacaine-IANB produced longer duration of action than 2% lidocaine-IANB (MD = 333.70 [267.33, 400.07], P < 0.001) and (MD = 288.01 [287.67, 288.34], P = 0.634, respectively). CONCLUSIONS: The network meta-analysis demonstrated that the intraosseous injection of 4% articaine with epinephrine had the most noteworthy success rate. However, the combination of BI and LI of 4% articaine with epinephrine, and IANB of 0.5% bupivacaine were, according to a VAS, the most effective. It should be noted that a rapid onset of action was produced by BI combined with LI of 4% articaine with epinephrine and IANB of 2% mepivacaine with epinephrine, while the most prolonged duration of action was generated by IANB of 0.5% levobupivacaine or 0.5% bupivacaine. CLINICAL RELEVANCE: For a better understanding of local anaesthesia for the extraction of the third molar, our study was aimed to provide evidence to guide better dental practices in pain management for clinicians.