OLFML3 REGULATES MICROGLIA FUNCTIONS VIA IBA1 DURING NEUROINFLAMMATION: INTERACTION AND EXPRESSION ANALYSIS

Neuroinflammation is a common pathophysiological mechanism involved in various neuropathologies. Olfactomedin-like 3 (Olfml3), a secreted glycoprotein, has emerged as a novel marker of microglia. However, its interacting partners and functional role in microglia and neuroinflammation remain elusive. The Olfml3 interacting proteins were screened using STRING, and Iba1, a key regulator of cytoskeletal dynamics and phagocytosis, was identified as a potential interactor. The three-dimensional structure of Olfml3 was predicted using homology modelling and docked with Iba1. This was followed by molecular dynamics simulation, which showed stable interaction of Olfml3 and Iba1 over time, indicating direct interaction at the structural level. Further, a chronic LPS-induced neuroinflammation model was established in male BALB/c mice (days 1-14; 750 μg/kg body weight) and delayed microglial modulation was introduced with minocycline (days 8-14; 50 mg/kg body weight). Behavioural parameters were evaluated to assess cognitive deficits and anhedonia. LPS administration showed neuroinflammation-associated cognitive impairment and affective disturbance. A significantly increased expression of Iba1, Olfml3, Tnf-α, while reduced Tgf-β and Bdnf, indicates a shift towards a pro-inflammatory microglial state. Olfml3 was found to co-localise with Iba1, implying possible involvement in microglial activation. Silencing of Olfml3 led to significant inhibition of Iba1 expression, indicating the presence of an Olfml3-Iba1 axis in the brain. Further, minocycline administration significantly improved behavioural outcomes and attenuated LPS-induced upregulation of Olfml3, Iba1 and Tnf-α expression while restoring Tgf-β and Bdnf expression. Taken together, the Olfml3-Iba1 axis could be a potential pharmacological target during neuroinflammation.