CUX1 promotes epithelial-mesenchymal transition (EMT) in renal fibrosis of UUO model by targeting MMP7

Levosimendan mitigates renal fibrosis via TGF-β1/Smad axis modulation in UUO rats

Chronic kidney disease (CKD) is characterized by kidney fibrosis involving epithelial-mesenchymal transition (EMT), and extracellular matrix (ECM) accumulation, and often leads to end-stage kidney disease (ESKD). Currently, available therapies are not uniformly effective and lead to serious adverse effects. Levosimendan (LVS), a calcium sensitizer and an inodilator, manages cardiac failure. We aimed to evaluate the renoprotective effect of LVS on unilateral ureteral obstruction (UUO)-induced CKD in male Sprague-Dawley (SD) rats and exogenous transforming growth factor-β1 (TGF-β1)-induced fibrosis in NRK-52E cells. Rats were randomly grouped as normal control (NC), sham, UUO and UUO + LVS (3 mg/kg, p.o., o.d.) for 21 days. All animals were sacrificed post-treatment, and plasma, urine and kidney specimens were utilized for biochemistry, histology, immunohistochemistry and immunoblotting. Moreover, exogenous TGF-β1 was used to stimulate kidney fibrosis in NRK-52E cells and treated with LVS (10 µM) for 48 h. The in-vitro samples were collected for cell morphology, viability, immunofluorescence and immunoblotting. LVS treatment significantly improved the kidney mass, plasma and urine creatinine, BUN, urine urea nitrogen and plasma proteins levels of TGF-β1 and fibronectin. Histology revealed a significant decrease in tubular necrosis, glomerulosclerosis and tubulointerstitial fibrosis in LVS-treated rats. Moreover, LVS treatment remarkably downregulated the levels of α-SMA, vimentin, p-Smad 2/3 and upregulated E-cadherin in UUO rats, decreased Smad 4, collagen I, β-catenin, and MMP-7-mediated ECM and increased Smurf 2 and Smad 7 in NRK-52E cells. LVS inhibits EMT and ECM turnover via TGF-β1/Smad axis modulation, highlighting the potential clinical use of LVS for CKD.

The Homeobox Transcription Factor CUX1 Coordinates Postnatal Epithelial Developmental Timing but Is Dispensable for Lung Organogenesis and Regeneration

Lung epithelial progenitors use a complex network of known and predicted transcriptional regulators to influence early lung development. In this study, we evaluated the function of one predicted regulator, CUX1, that we identified from transcriptional regulatory analysis of the SOX9+ distal lung progenitor network. We generated a new Cux1-floxed mouse model and created an epithelium-specific knockout of CUX1 using Shh-Cre (Cux1ShhCre-LOF). Postnatal Cux1ShhCre-LOF animals recapitulated key skin phenotypic features found in prior constitutive CUX1 knockout animals, confirming the functionality of our new floxed model. Postnatal Cux1ShhCre-LOF mice displayed subtle alveolar simplification and a transient delay in alveologenesis and alveolar type 1 cell development without persistent lung phenotypes. Cux1ShhCre-LOF mice developed failure to thrive in their second and third weeks of life because of delayed ileal maturation, which similarly resolves by Postnatal Day 35. Finally, we challenged Cux1ShhCre-LOF with influenza-mediated lung injury to demonstrate that Cux1ShhCre-LOF mice undergo productive alveolar regeneration that is indistinguishable from that in wild-type animals. Together, these findings indicate that epithelium-specific loss of CUX1 leads to transient developmental delays in the skin, lung, and intestine without defects in definitive organogenesis. We conclude that CUX1 function is required for temporal optimization of developmental maturation in multiple organs with implications for susceptibility windows in developmental disease pathogenesis.

Poricoic acid A attenuates renal fibrosis by inhibiting endoplasmic reticulum stress-mediated apoptosis

Renal fibrosis is a common manifestation in the progression of chronic kidney disease (CKD) to kidney failure. Currently, there is no available therapy to prevent the progression of renal fibrosis. Poricoic acid A (PAA) isolated from Poria cocos shows notable antifibrotic effects. However, its potential mechanism is still unclear. This study aimed to evaluate the effects and the potential mechanisms of PAA against renal fibrosis. A mouse model of renal fibrosis was established using unilateral ureteral obstruction (UUO). We showed that PAA administration significantly alleviated renal lesions and collagen deposition in UUO mice. Mice with UUO resulted in epithelial-to-mesenchymal transition (EMT) and the activation of endoplasmic reticulum stress (ERS) in the renal tissues, while PAA treatment significantly inhibited EMT and ERS activation. Additionally, PAA markedly alleviated ERS-mediated apoptosis in UUO mice. Molecular docking results indicated that PAA stably combined to GRP78 and ATF4. In conclusion, these results demonstrated that PAA possesses a significant bioactivity against renal fibrosis and its treatment mechanism might be the inhibition of ERS-mediated apoptosis.

Structure-Based Optimization and Biological Evaluation of Potent and Selective MMP-7 Inhibitors for Kidney Fibrosis

Matrix metalloproteinase-7 (MMP-7) has been shown to play important roles in pathophysiological processes involved in the development/progression of diseases such as cancer and fibrosis. We discovered selective MMP-7 inhibitors composed of arylsulfonamide, carboxylate, and short peptides by a molecular hybridization approach. These compounds interacted with MMP-7 via multiple hydrogen bonds in the cocrystal structures. To obtain compounds for in vivo evaluation, we attempted structural optimization, particularly targeting Tyr167 at the S3 subsite through structure-based drug design, and identified compound 15 as showing improved MMP-7 potency and MMP subtype selectivity. A novel π-π stacking interaction with Tyr167 was achieved when 4-pyridylalanine was introduced as the P3 residue. Compound 15 suppressed the progression of kidney fibrosis in a dose-dependent manner in a mouse model of unilateral ureteral obstruction. Thus, we demonstrated, for the first time, that potent and selective MMP-7 inhibitors could prevent the progression of kidney fibrosis.