Biology subjects

Maharjan, D. T.

Publications and source records attributed to Maharjan, D. T..

3 recordsLinked to original sources

bioRxiv2019

Keratin-Based Epidermal Green Autofluorescence is a Common Biomarker of Organ Injury

It is critical to discover biomarkers for non-invasive evaluation of the levels of inflammation and oxidative stress in human body - two key pathological factors in numerous diseases. Our study has indicated keratin 1-based epidermal autofluorescence (AF) as a biomarker of this type: Inducers of both inflammation and oxidative stress dose-dependently increased epidermal green AF with polyhedral structure in mice, with the AF intensity being highly associated with the dosages of the inducers. Lung cancer also induced increased epidermal green AF of mice, which was mediated by inflammation. Significant and asymmetrical increases in green AF intensity with polyhedral structure were found in the Dorsal Index Fingers skin of acute ischemic stroke (AIS) patients. While the AF intensity of the subjects with high risk for developing AIS, ischemic stroke patients in recovery phase and lung cancer patients was significantly higher than that of healthy controls, both AF intensity and AF asymmetry of these four groups were markedly lower than those of the AIS patients, which have shown promise for AIS diagnosis. Several lines of evidence have indicated K1 as an origin of the AF, e.g., K1 siRNA administration attenuated the oxidative stress-induced AF increase of mice. Collectively, our study has indicated K1-based epidermal AF as a biomarker for non-invasive evaluation of the levels of inflammation and oxidative stress in the body. These findings have established a basis for novel keratins AF-based biomedical imaging technology for non-invasive, efficient and economic diagnosis and screening of such inflammation- and oxidative stress-associated diseases as AIS.

biophysics↗

bioRxiv2018

Oxidative Stress Mediates UVC-Induced Increases in Epidermal Autofluorescence of C57 Mouse Ears

Our recent study has reported that UV-induced epidermal autofluorescence (AF) can be used as a novel biomarker for predicting UV-induced skin damage, which is originated from UV-induced, cysteine protease-mediated keratin 1 degradation. A key question regarding these findings is: Does oxidative stress play a significant role in the UV-induced epidermal AF and keratin 1 proteolysis? In our current study, we administered the widely used antioxidant N-acetyl cysteine (NAC) into the skin of mouse ears to test our hypothesis that oxidative stress mediates UV-induced increases in the epidermal AF and keratin 1 degradation. Our study has shown that NAC administration can significantly attenuate the UVC-induced AF increases. The NAC administration can also significantly decrease the UVC-induced keratin 1 degradation. Collectively, our findings have indicated that the oxidative stress induced by UVC is causative to the UVC-induced increases in epidermal AF and keratin 1 proteolysis. Moreover, since oxidative stress is significantly increased in multiple regions of the body in several major diseases, the oxidative stress-induced increases in epidermal AF may become a novel biomarker for diagnosis of major diseases.

biochemistry↗

bioRxiv2017

UV-Induced Keratin 1 Proteolysis Mediates UV-Induced Skin Damage

Keratins play critical roles in intermediate filament formation, inflammatory responses and cellular signaling in epithelium. While keratins is a major epidermal fluorophore, the mechanisms underlying the autofluorescence (AF) of keratins and its biomedical implications have remained unknown. Our study used mouse skin as a model to study these topics, showing that UV dose-dependently induced increases in green AF at the spinous layer of the epidermis of mouse within 6 hr of the UV exposures, which may be used for non-invasive prediction of UV-induced skin damage. The UV-induced AF appears to be induced by cysteine protease-mediated keratin 1 proteolysis: 1) UV rapidly induced significant keratin 1 degradation; 2) administration of keratin 1 siRNA largely decreased the UV-induced AF; and 3) administration of E-64, a cysteine protease inhibitor, significantly attenuated the UV-induced AF and keratin 1 degradation. Our study has also suggested that the UV-induced keratin 1 proteolysis may be a novel crucial pathological factor in UV-induced skin damage, which is supported by both the findings that indicate critical biological roles of keratin 1 in epithelium and our observation that prevention of UV-induced keratin 1 proteolysis can lead to decreased UV-induced skin damage. Collectively, our study has suggested that UV-induced keratin 1 proteolysis may be a novel and valuable target for diagnosis, prevention and treatment of UV-induced skin damage.

pathology↗