The functional role of MyD88 on cell death and locomotor recovery after spinal cord contusion

• Grant number: 19/09942-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: December 01, 2019
• End date: September 30, 2020
• Field of knowledge: Biological Sciences - Physiology - Physiology of Organs and Systems
• Principal Investigator: Alexandre Hiroaki Kihara
• Grantee: Giovanna Francisco Correa
• Host Institution: Centro de Matemática, Computação e Cognição (CMCC). Universidade Federal do ABC (UFABC). Ministério da Educação (Brasil). Santo André , SP, Brazil

Abstract

The spinal cord injury (SCI) is usually caused by severe falls, automobile accidents, injury with weapons and firearms, among others. SCI patients suffer both physically and psychologically since this condition often leads to paraplegia or quadriplegia, thus compromising motor, reflex and autonomic functions. Unfortunately, functional recover is not always possible due to the low regeneration capacity of nerve tissue. The first phase after SCI comprises the loss of cells and axonal disruption, while the second phase is characterized by spreading of secondary cell death, followed by prominent inflammation that contributes to the aggravation of the neural damage. In the context of neuroinflammation, the family of Toll-Like Receptors (TLRs) are able to recognize both pathogen - associated molecular patterns (PAMPs) and damage - associated molecular patterns (DAMPs) such as nucleic acids and proteins. Activation of TLRs generates intracellular signaling cascades that are mediated by myeloid differentiation primary response 88 (MyD88). MyD88 conveys signal transduction from TLRs, culminating in the activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) that is translocated to the nuclei increasing gene expression of inflammatory cytokines that leads to cellular apoptosis and impairment of tissue regeneration. However, little is known about the role of MyD88 - dependent pathway on SCI. Thus, the main purpose of this project is to study the role of MyD88 pathway in the development of secondary injury, in cellular apoptosis and recovery of motor function after mechanical SCI. For this, we intend to characterize MyD88 expression through immunofluorescence and western blot (WB) experiments. Next, we will evaluate the spread of secondary cell death by using the terminal kit deoxynucleotidyl transferase-mediated d-UTP nick end-labeling (TUNEL), activation of apoptotic pathway by western blot and motor recovery using the Basso Mouse Scale (BMS) comparing wild type and MyD88 knockout animals. With this, we intend to elucidate the main characteristics of this pathway when related to the signaling of neuroinflammation and with that, to contribute to the development of new treatment methods for the mechanical trauma of the spinal cord. All equipment and apparatus necessary to develop this project are available in Neurogenetics Lab as in other multiuser facilities at UFABC. This proposal will be supported by FAPESP (Auxílio Regular #2017/26439-0) and CNPq (Edital Universal B 431000/2016-6). (AU)