LRP5: A Multifaceted Co-Receptor in Development, Disease, and Therapeutic Target.

Low-density lipoprotein receptor-related protein 5 (LRP5) is a multifunctional transmembrane coreceptor that plays a pivotal role in development and disease. Wnt/β-catenin signaling is the primary downstream signaling pathway activated by LRP5. Furthermore, some LRP5 functions are mediated by noncanonical pathways, such as AKT/P21 and TGF-β/Smad signaling. Pathologically, both loss-of-function and gain-of-function mutations in LRP5 produce distinct phenotypes, ranging from osteoporosis-pseudoglioma syndrome to high bone mass disorders. Beyond the skeletal system, LRP5 has emerged as a key regulator of retinal angiogenesis, vascular integrity, renal tubular function, neurodevelopment, and lipid metabolism. Its physiological functions are highlighted by its ability to influence adipocyte differentiation, insulin sensitivity, and neuronal synaptic plasticity. Moreover, LRP5 displays a dual role in development and disease progression. Although it plays a protective role in acute injuries such as myocardial infarction and acute kidney injury, LRP5 also contributes to chronic pathologies such as tubulointerstitial fibrosis, polycystic kidney disease, and atherosclerosis through fibrotic and inflammatory pathways. Recent therapeutic interest has focused on modulating LRP5 activity using agents such as anti-Dickkopf-related protein 1 antibody, sclerostin inhibitors, polyclonal antibodies, CRISPR/Cas9 knockout, and some natural products. This review discusses the current understanding of LRP5's physiological and pathological roles across organ systems and highlights its therapeutic potential, emphasizing the need for targeted approaches considering its context-dependent effects.