Granzyme B deficiency promotes osteoblastic differentiation and calcification of vascular smooth muscle cells in hypoxic pulmonary hypertension

Abstract

Calcification is a major risk factor for vascular integrity. This pathological symptom and the underlying mechanisms in hypoxic pulmonary artery hypertension remain elusive. Here we report that pulmonary vascular medial calcification is elevated in pulmonary artery hypertension models as a result of an osteoblastic phenotype change of pulmonary arterial smooth muscle cells induced by hypoxia. Notably, inhibiting store-operated calcium channels significantly decreased osteoblastic differentiation and calcification of pulmonary arterial smooth muscle cells under hypoxia. We identified granzyme B, a major constituent of cytotoxic T lymphocytes/natural killer cell granules involved in apoptosis, as the main regulator of pulmonary arterial calcification. Overexpression of granzyme B blocked the mineralization through its effect on store-operated calcium channels in cultured pulmonary arterial smooth muscle cells under hypoxic conditions. Mice with overexpression of granzyme B exposed to hypoxia for 3 weeks showed attenuated vascular calcification and pathological progression of hypoxic pulmonary arterial hypertension. Our findings emphasize the central function of granzyme B in coordinating vascular calcification in hypoxic pulmonary arterial hypertension.

circRNA CDR1as Promotes Pulmonary Artery Smooth Muscle Cell Calcification by Upregulating CAMK2D and CNN3 via Sponging miR-7-5p

“… 13 , 27 , 28 Moreover, the combination of hypoxia and vascular calcification in the established PH rat models was identified in our previous study. 14 In this research, we confirmed that in HPASMCs, hypoxia treatment promoted the expression of bone-related proteins (Runx2, MSX2, BMP2, and SOX9) during calcification. More importantly, in the current study, we sought to characterize circRNAs involved in the regulation of HPASMC calcification and homeostasis.…”

“…ARS staining was performed as described previously. 14 In brief, HPASMCs were cultured with different treatments in pro-calcifying media containing 2.5 mM inorganic phosphate for the induction of calcification. After washing with PBS, the cells were fixed with 95% ethanol for 10 min and stained with ARS dye (pH 4.2) at 37°C for 30 min.…”

“… 9 , 10 , 11 , 12 Hypoxia plays a contributory role in triggering arterial calcification by increasing the expression of osteogenic markers and decreasing the expression of VSMC lineage markers. 13 , 14 It remains unclear how pathologic arterial calcification is activated by hypoxia in PH, specifically in human PASMCs (HPASMCs), where it has localized paracrine effects on the pulmonary vascular beds.…”

The Protective Effects of the Autophagic and Lysosomal Machinery in Vascular and Valvular Calcification: A Systematic Review

“…7-KC was shown to aggravate VCN by inducing lysosomal dysfunction and autophagosome accumulation [ 82 ] Lastly, granzyme B was degraded in hypoxia-induced pulmonary calcification by chaperone-mediated autophagy, characterized by an increase in Heat Shock Protein Family A (Hsp70) Member 8 (HSPA8) and lysosome-associated membrane protein 2 (LAMP2A). Conversely, granzyme B overexpression alleviated VCN both in vivo and in vitro [ 83 ].…”

“…Granzyme B, a cytotoxic serum protease protein, was demonstrated to mitigate hypoxia-induced pulmonary arterial calcification (PAC) [ 83 ]. However, during hypoxia, granzyme B was degraded by chaperone-mediated autophagy (CMA).…”