in-vivo-imaging-of-reactive-oxygen-species-in-a-murine-wound-model

<em>In Vivo</em> Imaging of Reactive Oxygen Species in a Murine Wound Model

The generation of reactive oxygen species (ROS) is a hallmark of inflammatory processes, but in excess, oxidative stress is widely implicated in various ...

New York University School of Medicine

Therapeutics utilizing siRNA are currently limited by the availability of safe and effective delivery systems. Cutaneous diseases, specifically ones with significant genetic components are ideal candidates for topical siRNA based therapy but the anatomical structure of skin presents a considerable hurdle. Here, we optimized a novel liposome and protein hybrid nanoparticle delivery system for the topical treatment of diabetic wounds with severe oxidative stress. We utilized a cationic lipid nanoparticle (CLN) composed of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) and the edge activator sodium cholate (NaChol), in a 6:1 ratio of DOTAP:NaChol (DNC). Addition of a cationic engineered supercharged coiled-coil protein (CSP) in a 10:1:1 ratio of DNC:CSP:siRNA produced a stable lipoproteoplex (LPP) nanoparticle, with optimal siRNA complexation, minimal cytotoxicity, and increased transfection efficacy. In a humanized murine diabetic wound healing model, our optimized LPP formulation successfully delivered siRNA targeted against Keap1, key repressor of Nrf2 which is a central regulator of redox mechanisms. Application of LPP complexing siKeap1 restored Nrf2 antioxidant function, accelerated diabetic tissue regeneration, and augmented reduction-oxidation homeostasis in the wound environment. Our topical LPP delivery system can readily be translated into clinical use for the treatment of diabetic wounds and can be extended to other cutaneous diseases with genetic components.

Novel lipoproteoplex delivers Keap1 siRNA based gene therapy to accelerate diabetic wound healing.

Despite improvements in awareness and treatment of type II diabetes mellitus (TIIDM), this disease remains a major source of morbidity and mortality worldwide, and prevalence continues to rise. Oxidative damage caused by free radicals has long been known to contribute to the pathogenesis and progression of TIIDM and its complications. Only recently, however, has the role of the Nrf2/Keap1/ARE master antioxidant pathway in diabetic dysfunction begun to be elucidated. There is accumulating evidence that this pathway is implicated in diabetic damage to the pancreas, heart, and skin, among other cell types and tissues. Animal studies and clinical trials have shown promising results suggesting that activation of this pathway can delay or reverse some of these impairments in TIIDM. In this review, we outline the role of oxidative damage and the Nrf2/Keap1/ARE pathway in TIIDM, focusing on current and future efforts to utilize this relationship as a therapeutic target for prevention, prognosis, and treatment of TIID.

The Nrf2/Keap1/ARE Pathway and Oxidative Stress as a Therapeutic Target in Type II Diabetes Mellitus.

Though unmitigated oxidative stress in diabetic chronic non-healing wounds poses a major therapeutic challenge, currently, there are no effective pharmacological agents. We targeted the cytoprotective Nrf2/Keap1 pathway, which is dysfunctional in diabetic skin and the regenerative environment in the diabetic wound. We assessed the efficacy of a potent Nrf2-activator, RTA 408, a semi-synthetic oleanane triterpenoid, on accelerating diabetic wound healing.

Targeted Nrf2 activation therapy with RTA 408 enhances regenerative capacity of diabetic wounds.

The molecular and cellular level reaches of the metabolic dysregulations that characterize diabetes are yet to be fully discovered. As mechanisms underlying management of reactive oxygen species (ROS) gain interest as crucial factors in cell integrity, questions arise about the role of redox cues in regulation and maintenance of bone marrow-derived multipotent stromal cells (BMSCs) that contribute to wound healing, particularly in diabetes. Through comparison of BMSCs from wild type and diabetic mice, with a known redox and metabolic disorder, we found that the cytoprotective Nrf2/Keap1 pathway is dysregulated and functionally insufficient in diabetic BMSCs. Nrf2 is basally active, but in chronic ROS we found irregular inhibition of Nrf2 by Keap1, altered metabolism and limited BMSC multipotency. Forced upregulation of Nrf2-directed transcription, through knockdown of Keap1, restores redox homeostasis. Normalized Nrf2/Keap1 signaling restores multipotent cell properties in diabetic BMSCs through Sox2 expression. These restored BMSCs can resume their role in regenerative tissue repair and promote healing of diabetic wounds. Knowledge of diabetes and hyperglycemia-induced deficits in BMSC regulation, and strategies to reverse them offers translational promise. Our study establishes Nrf2/Keap1 as a cytoprotective pathway, as well as a metabolic rheostat that affects cell maintenance and differentiation switches in BMSCs.

Piul S. Rabbani

Hansjörg Wyss Department of Plastic Surgery

New York University School of Medicine

In Vivo Imaging of Reactive Oxygen Species in a Murine Wound Model

Piul S. Rabbani

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Hansjörg Wyss Department of Plastic Surgery

New York University School of Medicine

In Vivo Imaging of Reactive Oxygen Species in a Murine Wound Model

Hansjörg Wyss Department of Plastic Surgery