TLR4-IN-C34 protects against acute kidney injury via modulating TLR4/MyD88/NF-κb axis, MAPK, and apoptosis

OBJECTIVES

Acute kidney injury (AKI) is a major component of isoproterenol (ISO) induced cardiorenal syndrome. In this study, we investigated the effect of TLR4-IN-C34 as a toll-like receptor (TLR)-4 inhibitor on ameliorating ISO-induced AKI and the possible molecular underlying pathways.

MATERIALS AND METHODS

The study included 4 groups: control group, ISO group (rats received 100 mg/kg ISO in 2 doses 24 hr apart, SC), ISO+C341 and ISO+C343 groups (rats received 1 or 3 mg/kg TLR4-IN-C34 respectively twice one hour before each ISO injection, IP).

RESULTS

Obtained results showed that TLR4-IN-C34 injection prior to ISO decreased serum creatinine level (P<0.05). Renal tissue histopathologic changes were markedly decreased by TLR4-IN-C34. Renal relative expression of MAPK and MyD88 mRNA decreased significantly in both ISO+C34₁ and ISO+C34₃ groups compared with the ISO group (P<0.05). Furthermore, TLR-IN-C34 lowered the inflammatory cytokines IL-8, IL-1β, and IL-12 renal levels (P<0.05). Immunostained kidney sections showed a marked decrease in NF-κb positive cells in addition to the apoptotic marker Bax (P<0.05) by the two tested doses of TLR4-IN-C34. On the other hand, the expression of the antiapoptotic marker Bcl-2 by renal cells was markedly increased.

CONCLUSION

It can be concluded that TLR4-IN-C34 ameliorates ISO-induced AKI through anti-inflammatory anti-apoptotic effects and modulation of TLR4 signaling pathways.

The NLRP3 inhibitor dapansutrile attenuates folic acid induced nephrotoxicity via inhibiting inflammasome/caspase-1/IL axis and regulating autophagy/proliferation

AIMS

Chemical renal toxicity is common and has limited therapeutic interventions. The NLRP3 inhibitor dapansutrile (DAPA) undergoes clinical phase II trials and it shows promising beneficial effects in various inflammatory diseases. The current study aims at evaluating the effect of DAPA on folic acid (FA) induced acute kidney injury (AKI) and its possible transition to chronic injury.

MATERIALS AND METHODS

Two treatment protocols were studied depending on DAPA injection timing. A prophylactic protocol involving the injection of DAPA (0.2 mg/kg) daily for seven days before FA challenge and a therapeutic protocol where DAPA was injected after FA. Each protocol included four groups of rats: control group, DAPA group, FA group and DAPA+FA group. Serum creatinine, urea and uric acid were measured. Also, kidney injury, necrosis and fibrosis percentage in addition to infiltration of CD68 positive cells were evaluated. Activation markers of inflammasome and the expression of Ki-67 and LC-3 were measured.

KEY FINDINGS

Results showed an improvement in renal tissue integrity and a significant decrease in kidney function biomarkers, caspase-1, IL-1β and IL-18 by DAPA injection (p < 0.05). In addition, DAPA decreased the proliferation marker Ki-67 and the autophagic marker LC-3 (p < 0.01).

SIGNIFICANCE

DAPA potentially alleviates FA induced nephrotoxicity through targeting inflammasome/caspase-1/IL axis. Moreover, it shows a regulatory effect on renal regeneration and autophagy.

Erlotinib can halt adenine induced nephrotoxicity in mice through modulating ERK1/2, STAT3, p53 and apoptotic pathways

Renal fibrosis is a failed regenerative process that facilitates chronic kidney disease progression. The current study was designed to study the effect of erlotinib, a receptor tyrosine kinase inhibitor, on the progression of renal fibrosis. The study included four groups of mice: control group; adenine group: received adenine (0.2% w/w) daily with food for 4 weeks; erlotinib group: received 80 mg/kg/day erlotinib orally (6 ml/kg/day, 1.3% w/v suspension in normal saline 0.9%) for 4 weeks; adenine + erlotinib group: received adenine and erlotinib concurrently. Kidney function and antioxidant biomarkers were measured. Renal expression of Bcl2 and p53 and histopathological changes (tubular injury and renal fibrosis) were scored. Renal tissue levels of transforming growth factor-β₁, p-ERK1/2 and p-STAT3 were measured. Results obtained showed significant decrease (P < 0.001) in serum creatinine, urea and uric acid in erlotinib + adenine group. Level of malondialdehyde was decreased significantly (P < 0.001) while reduced glutathione and catalase levels were increased (P < 0.01) by erlotinib concurrent administration. Erlotinib markedly reduced fibrosis and tubular injury and decreased TGF-β1, p-ERK1/2 and p-STAT3 (P < 0.5). In addition, expression level of Bcl-2 was elevated (P < 0.001) while that of p53-was reduced compared to adenine alone. Erlotinib can attenuate renal fibrosis development and progression through anti-fibrotic, antioxidant and anti-apoptotic pathways.

Modified citrus pectin stops progression of liver fibrosis by inhibiting galectin-3 and inducing apoptosis of stellate cells

Modified citrus pectin (MCP) is a pH modified form of the dietary soluble citrus peel fiber known as pectin. The current study aims at testing its effect on liver fibrosis progression. Rats were injected with CCl4 (1 mL/kg, 40% v/v, i.p., twice a week for 8 weeks). Concurrently, MCP (400 or 1200 mg/kg) was administered daily in drinking water from the first week in groups I and II (prophylactic model) and in the beginning of week 5 in groups III and IV (therapeutic model). Liver function biomarkers (ATL, AST, and ALP), fibrosis markers (laminin and hyaluronic acid), and antioxidant biomarkers (reduced glutathione (GSH) and superoxide dismutase (SOD)) were measured. Stained liver sections were scored for fibrosis and necroinflammation. Additionally, expression of galectin-3 (Gal-3), α-smooth muscle actin (SMA), tissue inhibitor metalloproteinase (TIMP)-1, collagen (Col)1A1, caspase (Cas)-3, and apoptosis related factor (FAS) were assigned. Modified pectin late administration significantly (p < 0.05) decreased malondialdehyde (MDA), TIMP-1, Col1A1, α-SMA, and Gal-3 levels and increased levels of FAS, Cas-3, GSH, and SOD. It also decreased percentage of fibrosis and necroinflammation significantly (p < 0.05). It can be concluded that MCP can attenuate liver fibrosis through an antioxidant effect, inhibition of Gal-3 mediated hepatic stellate cells activation, and induction of apoptosis.