WNK2 and diabetes mellitus: GRg1 demonstrates protective effects in conditions such as Alzheimer's disease (AD), Parkinson's disease (PD), ischemic stroke, cardiovascular dysfunction, diabetes, and aging, acting primarily through the nuclear factor kappa B (NF-κB), mitogen-activated protein kinase (MAPK), Wnt/β-catenin, and peroxisome proliferator-activated receptor gamma/heme oxygenase-1 (PPARγ/HO-1) signaling pathways.