Praziquantel pharmacotherapy reduces systemic osteopontin levels and liver collagen content in murine schistosomiasis mansoni

The critical role of osteopontin (OPN) in fibrotic diseases

Fibrosis is a pathological condition characterized by the excessive deposition of extracellular matrix components in tissues and organs, leading to progressive architectural remodelling and contributing to the development of various diseases. Osteopontin (OPN), a highly phosphorylated glycoprotein, has been increasingly recognized for its involvement in the progression of tissue fibrosis. This review provides a comprehensive overview of the genetic and protein structure of OPN and focuses on our current understanding of the role of OPN in the development of fibrosis in the lungs and other tissues. Additionally, special attention is given to the potential of OPN as a biomarker and a novel therapeutic target in the treatment of fibrosis.

MicroRNA-181b promotes schistosomiasis-induced hepatic fibrosis by targeting Smad7

Schistosomiasis is a common parasitic disease. Hepatosplenic schistosomiasis, caused by Schistosoma japonicum and Schistosoma mansoni, involves pathological changes, including worm egg-induced hepatic granuloma and fibrosis, which can markedly affect the liver's physiological functions. Although the drug praziquantel (PZQ) is used to treat schistosomiasis, drugs against schistosomiasis-induced liver fibrosis are rare in the clinical setting. Therefore, developing effective strategies to prevent and treat schistosomiasis-induced liver fibrosis is crucial. Previous studies have shown that miRNAs are involved in various liver diseases. In this study, we found a gradual increase in miR-181b expression in the murine liver as S. japonicum infection progressed, while the expression of Smad7 decreased. Down-regulating miR-181b significantly alleviated S. japonicum-induced hepatic granuloma and liver fibrosis. In vitro experiments showed that treatment with TGF-β1 upregulated miR-181b levels in the hepatic stellate cell (HSC) line LX2 in a concentration- and time-dependent manner. Downregulation of miR-181b significantly decreased collagen type I alpha 1 chain (COL1A1) expression in TGF-β1-stimulated LX2 cells. These findings indicate that miR-181b promotes HSC activation by down-regulating Smad7 expression, activating the TGF-β1/Smad signaling pathway, and leading to excess collagen expression and deposition. Our findings suggest that miR-181b might be a potentially novel therapeutic target for schistosomiasis-induced liver fibrosis.

Pyridoxal Kinase of Disease-causing Human Parasites: Structural and Functional Insights to Understand its Role in Drug Discovery

Abstract:

Human parasites cause several diseased conditions with high morbidity and mortality in a large section of the population residing in various geographical areas. Nearly three billion people suffer from either one or many parasitic infections globally, with almost one million deaths annually. In spite of extensive research and advancement in the medical field, no effective vaccine is available against prominent human parasitic diseases that necessitate identification of novel targets for designing specific inhibitors. Vitamin B6 is an important ubiquitous co-enzyme that participates in several biological processes and plays an important role in scavenging ROS (reactive oxygen species) along with providing resistance to oxidative stress. Moreover, the absence of the de novo vitamin B6 biosynthetic pathway in human parasites makes this pathway indispensable for the survival of these pathogens. Pyridoxal kinase (PdxK) is a crucial enzyme for vitamin B6 salvage pathway and participates in the process of vitamers B6 phosphorylation. Since the parasites are dependent on pyridoxal kinase for their survival and infectivity to the respective hosts, it is considered a promising candidate for drug discovery. The detailed structural analysis of PdxK from disease-causing parasites has provided insights into the catalytic mechanism of this enzyme as well as significant differences from their human counterpart. Simultaneously, structure-based studies have identified small lead molecules that can be exploited for drug discovery against protozoan parasites. The present review provides structural and functional highlights of pyridoxal kinase for its implication in developing novel and potent therapeutics to combat fatal parasitic diseases.