Ilomastat

Diabetic kidney disease (DKD) is a serious complication of diabetes patients with long time duration, presenting with albuminuria and/or a reduced estimated glomerular filtration rate (eGFR), and without symptoms of other primary causes of kidney injury. Clinical studies showed matrix metalloproteinase 2 (MMP2) is the potential indicator for DKD diagnosis. However, the typical measurement of MMP2 is complicated and time-consuming. Therefore, it is necessary to develop an easy and reliable approach for MMP2 detection. Herein, we proposed a reliable and easy-to-use nanopore solution for the quantitative measurement of MMP2 at the single-molecule level using α-hemolysin nanopore. Assisted by machine learning, the peptide substrate and peptide products digested by MMP2 were classified with 100 % accuracy. The quantitative range of MMP2 concentration was 50-400 ng/ml. We further investigated the inhibitory effects of MMP2 activity by different chemicals including Cu²⁺, Ni²⁺, Zn²⁺, EDTA, and its inhibitor GM6001. Finally, MMP2 measurement was explored in the presence of simulated urine. Our research provides a new solution of quantification of MMP2 activity combined with machine learning for DKD diagnosis.

Aberrant BMPR2 (bone morphogenetic protein receptor 2) signaling is associated with the pathogenesis of pulmonary hypertension. SMAD4 (mothers against decapentaplegic homolog 4) is an essential downstream effector of BMPR2 signaling, but whether and how it participates in pulmonary hypertension are unclear.

Globally and vascular cell-specifically inducible knockout mouse models were used to examine the role of SMAD4 deficiency in differential cell compartments in the development of pulmonary hypertension. Single-cell transcriptomic analysis in combination with in vitro cell function measurements was conducted to provide mechanistic insights into pulmonary hypertension pathogenesis.

Adult mice with Smad4 global deletion or endothelial cell-specific deletion spontaneously developed pulmonary hypertension manifestations, characterized by elevated right ventricle systolic pressure and excessive muscularization in pulmonary distal vessels, which were accompanied by other cardiovascular abnormalities. By contrast, mice with smooth muscle cell-specific Smad4 deletion had no pulmonary hypertension but rather displayed evident aortic aneurysm and dissection. At the cellular level, SMAD4 deficiency led to impairment of both endothelial cell-cell and cell-matrix adhesions and disorganized ECM (extracellular matrix), resulting in increased vascular leak and weakened endothelium-matrix attachment. Notably, endothelial Itgb1 deletion mimicked the impact of endothelial Smad4 loss on pulmonary hypertension. Finally, enhancing endothelial cell adhesion and ECM assembly by administrating an MMP (matrix metallopeptidase) inhibitor ilomastat could alleviate the pulmonary hypertension manifestations caused by endothelial SMAD4 deficiency.

SMAD4 deficiency in endothelial cells, but not smooth muscle cells, plays a pathogenic role in pulmonary hypertension, via dampening endothelial cell-cell and cell-matrix adhesions and ECM organization.