An Investigation into the Role of Arf6 in MCH-mediated Rearrangements in 3T3-L1 Preadipocytes

Abstract

Obesity has become a pandemic in our society. One potential method to alleviate this crisis is the use of pharmaceutical therapy to manage how our bodies metabolize the energy that we consume. Chronic overconsumption can lead to the activation of inflammatory responses and metabolic dysregulation, such as insulin resistance, and promote the obese condition. The pathways involved in the motility of pre-adipocyte cells are important in understanding how our bodies interpret and react to specific biochemical signals. This research is focused on a pathway that activates the expansion and migration of pre-adipocytes. Melanin-concentrating Hormone (MCH) is a neuropeptide that is known for regulating appetite and metabolism within adipocytes through the G protein-coupled receptor, MCHR1. MCHR1 is known to act through a Gq/PLC pathway to destabilize actin. Our proposed pathway is that MCHR1 activates ARNO, a guanine nucleotide exchange factor that is required in the subsequent activation of ADP-ribosylation factor 6 (Arf6). These events in succession may result in destabilized actin in murine 3T3-L1 pre-adipocytes. A pharmaceutical inhibitor of Arf6, NAV-2729, as well as the overexpression of dominant negative ARNO/Arf6 plasmids were used to determine if Arf6 was indeed a downstream signaling component in this pathway. Fluorescence microscopy was used to visualize the actin stress fibers and morphology of the cell and a scratch wound was performed to determine if the migration rate was affected. Preliminary results from our fluorescence stain show that the structure of actin was affected by NAV-2729 after MCH addition, however, additional trials and analysis are required.