Pimitespib, an HSP90 inhibitor, augments nifuroxazide-induced disruption in the IL-6/STAT3/HIF-1α autocrine loop in rats with bleomycin-challenged lungs: Evolutionary perspective in managing pulmonary fibrosis.

Idiopathic pulmonary fibrosis is a fatal lung disorder in which the etiology and pathogenesis are still unobvious. Effective treatments are urgently needed considering that lung transplantation is the only treatment that could improve outcomes. This study aimed to investigate the therapeutic significance of the dual administration of pimitespib, an HSP90 inhibitor, and nifuroxazide, a STAT3 inhibitor, against bleomycin-induced pulmonary fibrosis in rats. Our results revealed that pimitespib/nifuroxazide inhibited bleomycin-induced alterations in the structure and the function of the lungs. They demonstrated significant decreases in the BALF total and differential cell counts, LDH activity, and total protein. Concurrently, there was a reduction in the accumulation of collagen as proved by decreased hydroxyproline and the gene expression of COL1A1 accompanied by lower levels of PDGF-BB, TIMP-1, and TGF-ß. The levels of IL-6 were also downregulated. Pimitespib-induced inhibition of HSP90 led to subsequent inhibition of HIF-1α and STAT3 client proteins since the closed HSP90 would not enclose its client proteins. Therefore, pimitespib resulted in the repression of HIF-1α/CREB-p300 HAT as well as the STAT3/CREB-p300 HAT nuclear interactions. On the other hand, nifuroxazide resulted in a notable decline in pSTAT3 and HIF-1α levels. Subsequently, the combined effects of both drugs led to a substantial reduction in ECM deposition. Herein, pimitespib augmented nifuroxazide-induced disruption in the IL-6/STAT3/HIF-1α autocrine loop. Our findings also disclose that this novel loop is a promising therapeutic attack site for possible pulmonary fibrosis repression studies. Therefore, the use of pimitespib/nifuroxazide embodies an evolutionary perspective in managing pulmonary fibrosis.

Diacetylrhein, an anthraquinone antiarthritic agent, suppresses dextran sodium sulfate-induced inflammation in rats: A possible mechanism for a protective effect against ulcerative colitis.

Ulcerative colitis (UC) is a chronic inflammatory life-threatening and premalignant disorder with no cure that even might end up with surgical removal of a large section or even all of the colon. It is characterized by relapsing-remitting courses of intestinal inflammation and mucosal damage in which oxidative stress and exaggerated inflammatory response play a significant role. Most of the current medications to maintain remission are symptomatic and have many adverse reactions. Therefore, the potential for improved management of patients with UC continues to increase. Yet, the benefits of using the antiarthritic agent diacetylrhein to counteract inflammation in UC are still obscure. Hence, our study was designed to explore its potential role in UC using a model of dextran sodium sulfate-induced acute colitis in rats. Our results revealed that diacetylrhein targeted the NLRP3 and inhibited the inflammasome assembly. Consequently, caspase-1 activity and the inflammatory cytokines IL-1ß and IL-18 were inhibited leading to a curbed pyroptosis process. Additionally, diacetylrhein revealed a significant antiapoptotic potential as revealed by the levels of pro-apoptotic and anti-apoptotic proteins. Concomitant to these effects, diacetylrhein also interrupted NFκB signals leading to improved microscopic features of inflamed colon and decreased colon weight to length ratio, indices of disease activity, and macroscopic damage. Additionally, a reduction in the myeloperoxidase activity, IL-6, and TGF-ß alongside an increase in the gene expression of Ocln and ZO-1 were detected. To conclude diacetylrhein showed a significant antioxidant and anti-inflammatory potential and therefore might represent a promising agent in the management of acute UC.