Proteomic analysis of gut in Labeo rohita reveals ECM as Key Player in host's Response to Aeromonas hydrophila Infection

In the aquaculture sector, one of the challenges include disease outbreaks such as bacterial infections, particularly from Aeromonas hydrophila (Ah), impacting both wild and farmed fish. In this study, we conducted a proteomic analysis of the gut tissue in Labeo rohita following Ah infection to elucidate the protein alterations and its implications for immune response. Our findings reveal significant dysregulation in extracellular matrix (ECM) associated proteins during Ah infection, with increased abundance of elastin and Collagen alpha-3(VI) contributing to matrix rigidity. Pathway and enrichment analysis of differentially expressed proteins (DEPs) highlights the involvement of ECM-related pathways, including Focal adhesions, Integrin cell surface interactions, and actin cytoskeleton organization. Focal adhesions, crucial for connecting intracellular actin bundles to the ECM, play a pivotal role in immune response during infections. Increased abundance of integrin alpha 1, integrin beta 1, and Tetraspanin suggests their involvement in the host's response to Ah infection. Proteins associated with actin cytoskeleton reorganization, such as myosin, tropomyosin, and phosphoglucomutase, exhibit increased abundance, influencing changes in cell behavior. Additionally, upregulated proteins like LTBP1 and Fibrillin-2 contribute to TGF-beta signaling and focal adhesion, indicating their role in immune regulation. The study also identifies elevated levels of laminin, galectin 3, and tenascin-C, which interact with integrins and other ECM components, influencing immune cell migration and function. These proteins, along with decorin and lumican, act as immunomodulators, coordinating pro- and anti-inflammatory responses. ECM fragments released during pathogen invasion serve as "danger signals," initiating pathogen clearance and tissue repair through Toll-like receptor signaling.