Hepatoprotective Effects of Fused Pyridine Derivatives: Regulation of the TGF-β/Smad, miR-21/Smad7, and PPARγ Pathways in Carbon Tetrachloride-Induced Liver Fibrosis

Mahmoud Mohamed Khalil,1 Reem H Elhamammy,1 Hanan M Ragab,2 Mohamed Hussein Abdelgalil,1 Eman Sheta,3 Ahmed R Elaraby,4 Tamer M Ibrahim,5,6 Ahmed Wahid1 1Department of Biochemistry, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt; 2Department of Pharmaceutical Chemistry, College of Pharmacy, Al-Farahidi University, Baghdad, 10021, Iraq; 3Department of Pathology, Faculty of Medicine, Alexandria University, Alexandria, Egypt; 4Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Sinai University, Kantara Branch, Ismailia, Egypt; 5Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Kafrelsheikh University, Kafrelsheikh, Egypt; 6Department of Pharmaceutical Chemistry, Faculty of Pharmacy, The British University in Egypt, Al-Sherouk City, Cairo, EgyptCorrespondence: Ahmed Wahid, Department of Biochemistry, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt, Tel +201125566987, Email [email protected]: The liver functions as the body’s central metabolic organ, responsible for a wide array of vital processes, making its protection a key objective in medical research. Consequently, the promising hepatoprotective potential of several 4-phenyltetrahydroquinoline derivatives motivated us to comprehensively investigate the mechanisms of action of four newly synthesized compounds on carbon tetrachloride (CCl4)-induced liver injury in rats.Methods: Liver tissues and serum samples were collected from all experimental groups of Sprague-Dawley rats for histopathological examination, serological testing, RT-PCR, and ELISA. The mRNA expression levels of TGF-β, Smad2, α-SMA, Col1a1, Smad7, miR-21, and PPARγ, along with the protein levels of MMP-9 and TGF-β, were analyzed in liver tissues. Additionally, the HepG2 cell line was used for in vitro hepatotoxicity testing.Results: The mRNA expression of miR-21, Smad2, α-SMA, Col1A1, and TGF-β, as well as the protein levels of TGF-β and MMP-9, was reduced in rats treated with our compounds compared to CCl4-induced liver fibrosis in adult male Sprague-Dawley rats. Conversely, these compounds increased the mRNA expression of Smad7 and PPARγ. Additionally, the histopathological analysis showed a decrease in the degree of liver fibrosis following treatment with the tested compounds.Conclusion: The tested fused pyridine derivatives may protect the liver from fibrosis by modulating the TGF-β/Smad, miR-21-regulated TGF-β/Smad7, and PPARγ signaling pathways. These findings suggest that these derivatives could serve as novel agents for protecting the liver against fibrosis.Keywords: liver fibrosis, 4-phenyltetrahydroquinoline derivatives, rats, hepatotoxicity, CCl4, TGF-β, Smad, PPARγ, miR-21