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Usami, R.

Publications and source records attributed to Usami, R..

2 recordsLinked to original sources

Bioengineered iPSC Vessels Recapitulate Human Vascular Physiological Function and Aging Phenotypes

Vascular aging contributes to multisystem diseases and limits health span. Although various animal models have contributed to aging research, their vasculatures poorly recapitulate human physiology. Even existing tissue-engineered blood vessels fail to mimic human vascular function and pathology, hindering translational advances in vascular aging studies. Here, we present a novel human physiological vascular model fabricated via the unique molding-induced circumferential alignment of human induced pluripotent stem cell (iPSC)-derived vascular smooth muscle cells with luminally seeded endothelial cells. This architecture enabled dynamic vasodiameter changes in response to vasoactive stimuli, including hormones and intraluminal pressure. Using iPSCs from a patient with Werner syndrome, the model recapitulated aging-associated phenotypes, such as hypercontractility and increased vascular compliance, possibly due to impaired nitric oxide bioavailability. Transcriptomic and metabolomic analyses revealed age-related dysregulation consistent with vascular senescence. As a key advantage of the vasculature, spatial transcriptomic analysis demonstrated upregulation of the aging marker CDKN1A near the lumen and downregulation of COL6A1 and TPM1 throughout the vessel. Treatment with mitochonic acid 5, a mitochondria-targeted compound, significantly reversed the aging phenotypes. These findings demonstrate that our engineered vascular model recapitulates key aspects of human vascular properties and provides a platform for mechanistic studies of vascular aging and drug discovery aimed at extending health span.

bioengineering↗

Non-DNA-damaging DNA-PK activation improving hearing and prolonging life due to NAD+ and SIRT upregulation

Emerging evidence strongly supports a close relationship between age-related hearing loss and frailty, highlighting the importance of early detection and intervention. Recently, we invented a mitochondria-homing drug named mitochonic acid 5 (MA-5), that increases the adenosine triphosphate (ATP) levels, rescue mitochondrial function, and protect tissue damages. Currently, the phase I clinical trial has been finished in Japan (jRCT2031210495) and the phase 2 clinical trial has already been approved by PMDA. Here we show that MA-5 improved various types of hearing loss in mouse models. Structural chemical bioanalysis revealed that MA-5 is a mixture of equal amount of S- and R- enantiomer and both S- and R- enantiomer increase ATP by binding mitochondrial protein, mitofilin. However, S-enantiomer significantly increased the NAD+ levels by binding to the NAD+-producing key enzyme nicotinamide phosphoribosyltransferase (NAMPT). Moreover, the S-enantiomer increased the sirtuin 1 protein by suppressing polyubiquitination induced by tripartite motif containing 28 (TRIM28) phosphorylation which was triggered by DNA-dependent protein kinase (DNA-PK) activation in the absence of DNA damage. Transcriptomic signatures showed that the signature of MA-5 shows an inverse correlation with aging and mortality and is oriented in the same direction as the OSKM-related iPSCs, suggesting the modification of aging pathways. Oral administration of MA-5 to mitochondrial disease model mouse showed increased survival. Our findings suggest that, in addition to enhancing ATP levels, the coordinated regulation of NAD+ metabolism, SIRT protein expression, and DNA-PK activity-constituting a novel therapeutic triad may contribute to the amelioration of hearing impairment and mitochondrial dysfunction, thereby improving life prognosis.

cell biology↗