In vitro studies of the bidirectional interaction between renin angiotensin system and nicotine receptors

• Grant number: 23/05460-1
• Support Opportunities: Scholarships abroad - Research
• Start date: October 01, 2023
• End date: January 31, 2024
• Field of knowledge: Biological Sciences - Physiology - Physiology of Organs and Systems
• Principal Investigator: Carla Máximo Prado
• Grantee: Carla Máximo Prado
• Host Investigator: Ayman K. Hamouda
• Host Institution: Instituto de Saúde e Sociedade (ISS). Universidade Federal de São Paulo (UNIFESP). Campus Baixada Santista. Santos , SP, Brazil
• Institution abroad: University of Texas at Tyler (UT Tyler), United States

Abstract

The Renin-Angiotensin System (RAS) plays a fundamental role in maintaining organism homeostasis. Its effect on inflammation, particularly pulmonary, has gained prominence in recent years. The angiotensin converse enzyme 2 (ACE2), highly expressed in lung cells, has an important role in balancing the pro- and anti-inflammatory effects induced by the AT1R and MasR receptors, respectively. We demonstrated that overexpression of ACE2 induces a reduction in the expression of ±7, ±4, and ²2 subtypes of nicotinic acetylcholine receptors (nAChR) in BEAS-2B cells. High levels of ACE2 have been associated with increased SARS-COV-2 virus entry into the cell and with severe COVID-19 during the pandemic, such as the elderly and hypertensive individuals. The anti-inflammatory role of nAChRs has already been well-demonstrated, so understanding a possible relationship between ACE2 and nAChR is extremely relevant not only for advancing the pathophysiological mechanisms involved in various diseases, but also as new therapeutic targets. Aim: To elucidate whether there is a bidirectional interaction between ACE2 and nAChRs in vitro and whether this interaction affects the cellular response to acute injury. Materials and Methods: Wild-type and ACE2-overexpressing cells will be cultured and stimulated with lipopolysaccharide (LPS-exposed) or vehicle (control) then the expression level of ±7, ±4, and ²2 nAChRs will be evaluated by RT-qPCR and radioligand binding assays. Cytokine levels will be also evaluated to determine the level of cellular response. Then, control and LPS-exposed cells will be treated with nicotine or PNU 282987, an agonist of nAChR±7. In addition to the proposed above, the expression and activity of ACE2 and the expression of the AT1R and MasR receptors will also be evaluated. It is expected to provide a better understanding of the relationship between the renin-angiotensin system and nAChRs and the impact of this relationship on the lung cell response to LPS, a model that is widely used to mimic in vitro mechanisms of Acute Respiratory Distress Syndrome. (AU)