Banca de QUALIFICAÇÃO: THÉO HENRIQUE DE LIMA VASCONCELLOS
Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.STUDENT : THÉO HENRIQUE DE LIMA VASCONCELLOS
DATE: 11/08/2023
TIME: 13:00
LOCAL: Sala 211 do Bloco Zeta do Campus de São Bernardo do Campo da Universidade Federal do ABC
TITLE:
ETHANOL AGGRAVATES NEUROINFLAMMATION TRIGGERED BY OXIDATIVE STRESS: THE ROLE OF INTRACELLULAR CALCIUM STORES IN RETINAL DEGENERATION
PAGES: 82
BIG AREA: Ciências Biológicas
AREA: Fisiologia
SUBÁREA: Fisiologia de Órgãos e Sistemas
SPECIALTY: Neurofisiologia
SUMMARY:
The retina is a photosensitive neuroepithelium in the inner eye region and is considered an integral component of the central nervous system (CNS). An imbalance in the physiological conditions or changes in the number of functional photoreceptors can lead to critical visual deficits. One such disease that virtually leads to vision impairment is retinitis pigmentosa (RP). Among the causes of autosomal recessive RP (arRP) are mutations in the PDE6B gene, culminating in rod-type photoreceptors' initial cell death and cones' subsequent degradation. However, the processes underlying the primary rod cell death are not fully known, although studies point to mechanisms involved in the inflammatory response, oxidative and metabolic stress, epigenetic factors, and calcium dysregulation. Among the latter, the type 1 inositol-1,4,5-triphosphate receptor (IP3R1), responsible for intracellular calcium homeostasis, could participate in the progression of this pathology. IP3R1 is associated with several cellular events, such as cell death and proliferation. In animal models for autosomal recessive RP, several alterations related to calcium dysregulation, like mitochondrial and endoplasmic reticulum overload, have been described, affecting the photoreceptors' metabolism. In this scenario, this project aims to describe an in vitro model of double-hit of oxidative stress, description of IP3R1 subcellular pattern in the retina comparing wild-type animal (C57BL/6) vs. an animal model of arRP (C3H/HeJ), and analyze the effects of the pharmacological blocking of IP3R1 in both in vitro and in vivo neurodegenerative models with an IP3R1 inhibitor 2-Aminoethyl diphenylborinate (2-APB), focusing on analyses of glial cells and inflammatory aspects. Here, we described our in vitro double-hit model, that consists of addition of H2O2 for 24 hours, and prior to the second hit, the pre-treatment for 30 minutes of vehicle or 2-APB, and finally adding ethanol (EtOH) as second hit. The idea of this experimental design is to understand the role of IP3R1 in neurodegeneration, linked by stress oxidative, also, the cells utilized in vitro does not have mutations on TLR4. Our analysis showed that our model led to strong neuroinflammatory reaction in microglia cells, rescued by 2-APB treatment, with morphologic alterations, and prevalence of anti-inflammatory phenotype in these conditions. Astrocytes remain altered even with 2-APB treatment. The number of neurons has increased, and these are more branched - indicating a possible neuroprotection effect of pharmacological intervention of IP3R1 by 2-APB in vitro. Our descriptive results of IP3R1 subcellular distribution in wilt-type and arRP mice showed a translocation of this protein to the lesion site in mid to late degeneration, indicating a possible role of IP3R1 in this disease progression, furthermore a potential target for arRP. The pharmacological intervention in arRP mice was performed using 2-APB by subretinal injection, our results showed no alterations in retinal morphometry either in thickness and by TUNEL assay, with 2-APB not rescuing photoreceptor cells. The macroglial cells were not altered, by microglia showed smaller size, and higher number in the outer retina compared to control. By multiplex cytokine analysis is possible to note a reduction of several cytokines: IL-17, TNF-α, IL-10, and IL-13, with a disorganization of the inflammatory response. With these results, we intended to evaluate the role of the IP3R1 protein in the progression of arRP, and its role in neuroinflammatory processes, which may open perspectives for therapies focused on calcium dysregulation.
COMMITTEE MEMBERS:
Presidente - Interno ao Programa - 1887027 - FERNANDO AUGUSTO DE OLIVEIRA RIBEIRO
Membro Titular - Examinador(a) Interno ao Programa - 1544365 - GISELLE CERCHIARO
Membro Titular - Examinador(a) Interno ao Programa - 1674592 - TIAGO RODRIGUES
Membro Suplente - Examinador(a) Interno ao Programa - 3066269 - VINICIUS DE ANDRADE OLIVEIRA