Jeon, Y.-M. | bioRxiv Science

bioRxiv2026

Supplemental deinoxanthin ameliorates bone marrow microenvironmental impairments and recovers functional damage of bone marrow-retained cells in total body irradiation-exposed mice

Total body irradiation (TBI) can impair the bone marrow (BM) microenvironment and dysregulate the fates of BM-residing cells by overproducing reactive oxygen species (ROS) and inflammatory mediators. This study aims to investigate the potency and mechanism of Deinococcus radiodurans-derived deinoxanthin (DEIX) in mitigating TBI-mediated injuries in the BM microenvironment and BM-resident cells. C57BL/6 mice were divided into control, TBI, TBI+DEIX, and/or DEIX groups, in which the mice were exposed to sub-lethal TBI (5 Gy) or in combination with oral DEIX supplementation (25 mg/kg body weight). While the DEIXs effect on BM and BM-resident cells was determined after five weeks of TBI, RNA sequence profiling on the mouse group-derived BM cells was performed after two weeks of TBI. Supplementation with DEIX protected mice against TBI-mediated decrease in bone mineral density of trabecular bones. Supplemental DEIX suppressed BM microenvironmental impairment and the induction of oxidative stress and senescence in BM cells of TBI-exposed mice. That suppression was orchestrated by the DEIX-induced restoration of TBI-stimulated disorders in osteogenic, osteoclastogenic, and adipogenic activation in the BM. Ex vivo assays using BM cells supported the notion that DEIX restores TBI-mediated defects in BM cell function, including colony formation, migration, and differentiation. RNA sequence profiling demonstrated DEIXs potency to modulate the expression of genes that regulate cellular and systemic immune responses, cell proliferation and differentiation, and bone metabolism. Collectively, our results highlight the roles and associated mechanisms of DEIX in mitigating TBI-mediated microenvironmental impairment and in regulating BM-resident cells.

cell biology↗

bioRxiv2018

PTK2 regulates the UPS impairment via p62 phosphorylation in TDP-43 proteinopathy

TDP-43 proteinopathy is a common feature in a variety of neurodegenerative disorders including Amyotrophic lateral sclerosis (ALS) cases, Frontotemporal lobar degeneration (FTLD), and Alzheimers disease. However, the molecular mechanisms underlying TDP-43-induced neurotoxicity are largely unknown. In this study, we demonstrated that TDP-43 proteinopathy induces impairment in ubiquitin-proteasome system (UPS) evidenced by an accumulation of ubiquitinated proteins and reduction of proteasome activity in neuronal cells. Through kinase inhibitor screening, we identified PTK2 as a suppressor of neurotoxicity induced by UPS impairment. Importantly, PTK2 inhibition significantly reduces ubiquitin aggregates and attenuated TDP-43-induced cytotoxicity in Drosophila model of TDP-43 proteinopathy. We further identified that phosphorylation of p62 at serine 403 (p-p62S403), a key component in the autophagic degradation of poly-ubiquitinated proteins, is increased upon TDP-43 overexpression and dependent on activation of PTK2 in neuronal cells. Moreover, expressing a non-phosphorylated form of p62 (p62S403A) significantly represses accumulation of polyubiquitinated proteins and neurotoxicity induced by TDP-43 overexpression in neuronal cells. In addition, inhibition of TBK1, a kinase which phosphorylates S403 of p62, ameliorates neurotoxicity upon UPS impairment in neuronal cells. Taken together, our data suggest that activation of PTK2-TBK1-p62 axis plays a critical role in the pathogenesis of TDP-43 by regulating neurotoxicity induced by UPS impairment. Therefore, targeting PTK2-TBK1-p62 axis may represent a novel therapeutic intervention for neurodegenerative diseases with TDP-43 proteinopathy.

neuroscience↗