2016 — 2019 |
Sharma, Shruti |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Targeting Interleukin-6 Trans-Signaling in Diabetic Retinopathy @ Georgia Regents University
Project Summary Diabetic retinopathy (DR) is a sight-threatening neurovasculopathy, which is the leading cause of blindness in working-aged Americans. The new therapies to prevent retinal injury and enhance repair is a critical unmet need. The main focus of this proposal is to test a novel pharmacological compound sgp130Fc for the treatment of DR. Interleukin-6 (IL-6) is the major mediator of inflammation and increasing evidence suggests that the IL-6 pathway plays a prominent role in the pathogenesis of DR. Interestingly, even though the retinal endothelial cells lack membrane bound IL-6 receptor, IL-6 mediated signaling is observed in these cells. Studies have shown that IL-6/soluble IL-6R complex can bind to glycoprotein 130 (gp130) to initiate downstream signaling in cells that do not express the IL-6 receptor and this process is known as IL-6 trans-signaling. Current approaches to block IL-6 signaling inhibit both classical and trans-signaling pathways. Recent studies suggest that IL-6 trans-signaling is particularly important in regulating processes localized to the site of disease or infection and is crucially involved in inflammatory diseases. We hypothesize that inhibiting only the trans-signaling pathway of IL-6 will be superior to complete IL-6 blockade, because important physiologic functions of IL-6 will remain intact. This novel intervention strategy represents the first attempt to investigate the effects of selective IL-6 trans-signaling blockade in DR treatment. We have exciting preliminary data showing that inhibition of IL-6 trans-signaling significantly decreases the inflammatory response in human retinal endothelial cells and diabetic mice retina. In this proposal we will test the hypothesis that sgp130-Fc will slow disease progression and attenuate pathological ocular inflammation in diabetic retinopathy, when administered either prior to onset of DR or later at a clinically evident disease stage. In Aim-1, we will use in vitro approaches to determine the effects of IL-6 trans-signaling on endothelial-pericyte interaction, expression of adhesion and tight junctions molecules in the endothelial system, maintenance of barrier function, pericyte migration, ROS production, apoptosis and proliferation of endothelial cells and pericytes. In Aim-2, we will use the streptozotocin (STZ)-induced type-1 diabetes (T1D) mouse model to determine the effect of sgp130Fc drug treatment on the diabetes-induced retinal vascular pathology by conducting molecular, structural and functional studies in diabetic mice retinas. This project has the potential to provide a new therapeutic approach to treat retinal vascular pathology associated with diabetes.
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0.957 |
2019 — 2021 |
Sharma, Shruti |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Intracellular Nucleic Acid Sensing and Age-Related Chronic Inflammation @ Tufts University Boston
Chronic inflammation is a common pathological basis for age-associated increases in autoimmunity, diabetes, cancer, cardiovascular and Alzheimer?s disease as well as shortened lifespan. Failure to resolve an activated innate immune response contributes significantly to chronic inflammation. Despite the profound clinical implications, the specific innate pathways contributing to chronic inflammation remain unknown. We reasoned that age-associated accrual of damaged DNA, which in other settings is a known driver of inflammation through cell-intrinsic DNA-sensing pathways, may contribute to age-associated chronic inflammation through these same innate pathways. Notably, cell-intrinsic DNA-sensing pathways require the participation of the DNA-sensor, cGAS and ER-resident adaptor, STING and are potent inducers of the pleiotropic cytokine family, type I interferons (IFN-I). IFN-I have been linked to chronic inflammation in disorders such as autoimmunity and cancer. While the molecular components of age-associated chronic inflammation remain undefined, a significant body of work suggests that recirculating innate cells may be compromised, however, the contribution of tissue resident macrophages to aging has not been addressed. Tissue macrophages are distinct from other myeloid-derived cells, not only in their origins, but also because they integrate epigenetic and microenvironment cues to carry out a unique set of functions. In addition to mounting innate immune responses, tissue macrophages are indispensable for tissue patterning, resolution of inflammation and tissue repair. Here we propose to test the hypothesis that cytosolic DNA-sensing promotes constitutive IFN-I induction within tissue macrophages and drives age-associated chronic inflammation. We will systematically address how specific innate processes contribute to immune dysfunction in the elderly in three specific aims. 1) We will evaluate the contribution of cytosolic DNA-sensing pathways to aging-associated constitutive IFN-I and proinflammatory signatures in tissues and resident macrophages using mice deficient in cGAS and STING. 2) We will determine the direct contribution cytosolic DNA sensing pathways in exclusively shaping tissue macrophage fate and function with age by conditionally deleting STING directly in tissue macrophage progenitors. As the epigenomes and transcriptomes of tissue macrophages are highly plastic, we will utilize next generation sequencing to identify genome-wide changes instigated by cytosolic DNA-sensing pathways in these cells with progressive age. 3) Finally, we will extend our findings to humans and determine the baseline IFN-I signatures and responsiveness of tissue macrophages from the lungs of geriatric patients and correlate them to well-represented loss-of-function haplotypes of STING. By uncovering the molecular details of chronic inflammation in aging humans, the findings from this study offer new immunomodulatory strategies and targets to bolster protective immunity as well as block detrimental inflammation, as desired, during aging.
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0.942 |