Biology subjects

Saito, J.

Publications and source records attributed to Saito, J..

3 recordsLinked to original sources

bioRxiv2024

Sphingosine kinase 1 is integral for elastin deficiency-induced arterial hypermuscularization

Defective elastin and smooth muscle cell (SMC) accumulation characterize both arterial diseases (e.g., atherosclerosis, restenosis and supravalvular aortic stenosis [SVAS]), and physiological ductus arteriosus (DA) closure. Elastin deficiency induces SMC hyperproliferation; however, mechanisms underlying this effect are not well elucidated. Elastin (ELN) is expressed from embryonic day (E) 14 in the mouse aorta. Immunostains of Eln(+/+) and Eln(-/-) aortas indicate that SMCs of the Eln null aorta are first hyperproliferative at E15.5, prior to morphological differences. Bulk RNA-seq reveals that sphingosine kinase 1 (Sphk1) is the most upregulated transcript in Eln(-/-) aortic SMCs at E15.5. Reduced ELN increases levels of transcription factor early growth response 1 (EGR1), resulting in increased SPHK1 levels in cultured human aortic SMCs and in the mouse aorta at E15.5 and P0.5. Aortic tissue from Williams-Beuren Syndrome patients, who have elastin insufficiency and SVAS, also has upregulated SPHK1 expression. SMC-specific Sphk1 deletion or pharmacological inhibition of SPHK1 attenuates SMC proliferation and mitigates aortic disease, leading to extended survival of Eln(-/-) mice. In addition, EGR1 and SPHK1 are increased in the wild-type mouse DA compared to adjacent descending aorta. Treatment with a SPHK1 inhibitor attenuates SMC proliferation and reduces SMC accumulation, leading to DA patency. In sum, SPHK1 is a key node in elastin deficiency-induced hypermuscularization, and inhibiting this kinase may be a therapeutic strategy for SVAS and select congenital heart diseases in which a patent DA maintains circulation. One Sentence SummarySphingosine kinase 1-induced by defective elastin promotes muscularization in pathological aortic stenosis and physiological ductus arteriosus occlusion.

developmental biology↗

bioRxiv2024

Investigating Novel Streptomyces Bacteriophage Endolysins as Potential Antimicrobial Agents

BackgroundAs antibiotic resistance has become a major global threat; the World Health Organization (WHO) has urgently called for alternative strategies for control of bacterial infections. Endolysin, a phage-encoded protein, can degrade bacterial peptidoglycan (PG) and disrupt bacterial growth. According to the WHO, there are only three endolysin products currently in clinical phase development. In this study we explore novel endolysins from Streptomyces phages as only a few of them have been experimentally characterized. Using several bioinformatics tools, we identified nine different functional domain combinations from 250 Streptomyces phages putative endolysins. LazerLemon gp35 (CHAP; LL35lys), Nabi gp26 (amidase; Nb26lys), and Tribute gp42 (PGRP/amidase; Tb42lys) were selected for experimental studies. We hypothesized that (1) the proteins of interest will have the ability to degrade purified PG, and (2) the proteins will have potential antimicrobial activity against bacteria from families of importance in antibiotic resistance, such as ESKAPE safe relatives (Enterococcus raffinosus, Staphylococcus epidermidis, Klebsiella aerogenes, Acinetobacter baylyi, Pseudomonas putida, and Escherichia coli). ResultsLL35lys, Nb26lys, and Tb42lys exhibit PG-degrading activity on zymography and hydrolysis assay. The enzymes (100 {micro}g/mL) can reduce PG turbidity to 32-40%. The killing assay suggests that Tb42lys has a broader range (E. coli, P. putida, A. baylyi and K. aerogenes). While Nb26lys better attacks Gram-negative than Gram-positive bacteria, LL35lys can only reduce the growth of the Gram-positive ESKAPE strains but does so effectively with a low MIC90 of 2 {micro}g/mL. A higher concentration ([≥]300 {micro}g/mL) of Nb26lys is needed to inhibit P. putida and K. aerogenes. ConclusionFrom 250 putative endolysins, bioinformatic methods were used to select three putative endolysins for cloning and study: LL35lys, Nb26lys, and Tb42lys. All have shown PG-degrading activity, a critical function of endolysin. With a low MIC, LL35lys shows activity for the Gram-positive ESKAPE strains, while Nb26lys and Tb42lys are active against the Gram-negatives. Therefore, endolysins from Streptomyces phage have potential as possible antimicrobial agents against ESKAPE bacteria.

microbiology↗

bioRxiv2023

Loss of presenilin-1 in smooth muscle cells ameliorates elastin aortopathy

Smooth muscle cell (SMC) accumulation is central to the pathogenesis of elastin-defective arterial diseases, such as atherosclerosis, pulmonary hypertension and supravalvular aortic stenosis (SVAS). We previously demonstrated that elastin insufficiency activates the Notch pathway in aortic SMCs, resulting in hypermuscularization. Activation of Notch is catalyzed by the enzyme gamma-secretase, but the role of specific catalytic subunits PSEN-1 or PSEN-2 in elastin aortopathy is not defined. This study utilizes genetic approaches to query the role of PSEN-1/2 in the pathogenesis of elastin mutant mice, which model human SVAS. Although endothelial cell-specific Psen1 deletion does not improve elastin aortopathy, deletion of either Psen1 in SMCs or Psen2 globally attenuates Notch downstream gene expression and SMC proliferation, mitigating aortic disease. With SMC-specific Psen1 deletion in elastin nulls, these rescue effects are more robust and in fact, survival is increased. On the background of Psen1 deletion in SMCs, global Psen2 deletion yields additional benefits in regard to elastin aortopathy. Finally, SMC deletion of Psen1 also attenuates hypermuscularization in newborns heterozygous for the elastin null gene, which genetically mimics SVAS. Taken together, these findings put forth SMC PSEN-1 as a potential therapeutic target in elastin aortopathy.

developmental biology↗