Calponin 1 inhibits agonist-induced ERK activation and decreases calcium sensitization in vascular smooth muscle.

Smooth muscle cell (SMC) contraction and vascular tone are modulated by phosphorylation and multiple modifications of the thick filament, and thin filament regulation of SMC contraction has been reported to involve extracellular regulated kinase (ERK). Previous studies in ferrets suggest that the actin-binding protein, calponin 1 (CNN1), acts as a scaffold linking protein kinase C (PKC), Raf, MEK and ERK, promoting PKC-dependent ERK activation. To gain further insight into this function of CNN1 in ERK activation and the regulation of SMC contractility in mice, we generated a novel Calponin 1 knockout mouse (Cnn1 KO) by a single base substitution in an intronic CArG box that preferentially abolishes expression of CNN1 in vascular SMCs. Using this new Cnn1 KO mouse, we show that ablation of CNN1 has two effects, depending on the cytosolic free calcium level: (1) in the presence of elevated intracellular calcium caused by agonist stimulation, Cnn1 KO mice display a reduced amplitude of stress and stiffness but an increase in agonist-induced ERK activation; and (2) during intracellular calcium depletion, in the presence of an agonist, Cnn1 KO mice exhibit increased duration of SM tone maintenance. Together, these results suggest that CNN1 plays an important and complex modulatory role in SMC contractile tone amplitude and maintenance.

Intracellular localization of MyosinXXI discriminates Leishmania spp and Leptomonasseymouri.

The patients with the most dreaded Leishmania donovani infections are now regularly been detected with co-infecting monoxenous trypanosomatid, Leptomonas seymouri, of which pathological consequence is obscure. Due to high degree of morphological similarity, its presence remains unmarked in the culture which leads to anomalous research outcomes. The available methods to detect Leptomonas in cultures are cumbersome and are not quantitative. We report here that MyosinXXI serves as a distinguishing biomarker that can be used to mark the presence of L. seymouri in Leishmania cultures. The method uses Leishmania MyosinXXI antibodies employed in immunofluorescence microscopy that shows a specialized localization pattern in Leishmania but not in Leptomonas (Patent application No. IN201711014439). This method is not only qualitative, but can also quantify the L. seymouri load in the cultured field isolates and serves as a remarkable tool to ascertain laboratory strains of Leishmania.

Vascular aging, the vascular cytoskeleton and aortic stiffness.

Vascular aging, aortic stiffness and hypertension are mechanistically interrelated. The perspective presented here will focus mainly on the molecular mechanisms of age-associated increases in the stiffness of the vascular smooth muscle cell (VSMC). This review will highlight the mechanisms by which the VSMC contributes to disorders of vascular aging. Distinct functional sub-components of the vascular cell and the molecular mechanisms of the protein-protein interactions, signaling mechanisms and intracellular trafficking processes in the setting of the aging aorta will be detailed.