Alzheimer’s disease (AD) stands as the predominant form of dementia, presenting significant and escalating global challenges. Its etiology is intricate and diverse, stemming from a combination of factors such as aging, genetics, and environment. Our current understanding of AD pathologies involves various hypotheses, such as the cholinergic, amyloid, tau protein, inflammatory, oxidative stress, metal ion, glutamate excitotoxicity, microbiota-gut-brain axis, and abnormal autophagy. Nonetheless, unraveling the interplay among these pathological aspects and pinpointing the primary initiators of AD require further elucidation and validation. In the past decades, most clinical drugs have been discontinued due to limited effectiveness or adverse effects. Presently, available drugs primarily offer symptomatic relief and often accompanied by undesirable side effects. However, recent approvals of aducanumab (1) and lecanemab (2) by the Food and Drug Administration (FDA) present the potential in disrease-modifying effects. Nevertheless, the long-term efficacy and safety of these drugs need further validation. Consequently, the quest for safer and more effective AD drugs persists as a formidable and pressing task. This review discusses the current understanding of AD pathogenesis, advances in diagnostic biomarkers, the latest updates of clinical trials, and emerging technologies for AD drug development. We highlight recent progress in the discovery of selective inhibitors, dual-target inhibitors, allosteric modulators, covalent inhibitors, proteolysis-targeting chimeras (PROTACs), and protein-protein interaction (PPI) modulators. Our goal is to provide insights into the prospective development and clinical application of novel AD drugs.

The overactivation of transient receptor potential canonical 3 (TRPC3) is associated with neurodegenerative diseases and hypertension. Pyrazole 3 (Pyr3) is reported as the most selective TRPC3 inhibitor, but it has two inherent structural limitations: (1) the labile ester moiety leads to its rapid hydrolysis to the inactive Pyr8 in vivo, and (2) the alkylating trichloroacrylic amide moiety is known to be toxic. To circumvent these limitations, we designed a series of conformationally restricted Pyr3 analogues and reported that compound 20 maintains high potency and selectivity for human TRPC3 over its closely related TRP channels. It has significantly improved metabolic stability compared with Pyr3 and has a good safety profile. Preliminary evaluation of 20 demonstrated its ability to rescue Aβ-induced neuron damage with similar potency to that of Pyr3 in vitro. Collectively, these results suggest that 20 represents a promising scaffold to potentially ameliorate the symptoms associated with TRPC3-mediated neurological and cardiovascular disorders.

To investigate how dysregulated transient receptor potential canonical channels (TRPCs) are associated with Alzheimer’s disease (AD), we challenged primary neurons with amyloid-β (Aβ). Both the naturally secreted or synthetic Aβ oligomers (AβOs) induced long-lasting increased TRPC3 and downregulated the TRPC6 expression in mature excitatory neurons (CaMKIIα-high) via a Ca²⁺-dependent calcineurin-coupled NFAT transcriptionally and calpain-mediated protein degradation, respectively. The TRPC3 expression was also found to be upregulated in pyramidal neurons of human AD brains. The selective downregulation of the Trpc6 gene induced synaptotoxicity, while no significant effect was observed from the Trpc3-targeting siRNA, suggesting potentially differential roles of TRPC3 and 6 in modulating the synaptic morphology and functions. Electrophysiological recordings of mouse hippocampal slices overexpressing TRPC3 revealed increased neuronal hyperactivity upon the TRPC3 channel activation by its agonist. Furthermore, the AβO-mediated synaptotoxicity appeared to be positively correlated with the degrees of the induced dendritic Ca²⁺ flux in neurons, which was completely prevented by the co-treatment with two pyrazole-based TRPC3-selective antagonists Pyr3 or Pyr10. Taken together, our findings suggest that the aberrantly upregulated TRPC3 is another ion channel critically contributing to the process of AβO-induced Ca²⁺ overload, neuronal hyperexcitation, and synaptotoxicity, thus representing a potential therapeutic target of AD.

Calcium dysregulation is increasingly recognized as a convergent mechanism underlying neuronal vulnerability and glial overactivation in Alzheimer's disease (AD). Transient Receptor Potential Canonical (TRPC) channels are potential key modulators of Ca ²⁺ signaling in multiple cell types in central nervous system (CNS), mediating different pathophysiological roles. However, their cell type‐specific remodeling and cellular origins of these changes in human AD tissue remain poorly defined. This study investigated their expression patterns with main focus on the two closely related members of TRPC3 and TRPC6 across human AD brains and two relevant mouse models. Formalin‐fixed paraffin‐embedded cortical and hippocampal tissues from AD patients and age‐matched controls were examined using immunohistochemistry. Spatial relationships between TRPC3/TRPC6 and glial fibrillary acidic protein (GFAP)‐positive astrocytes were assessed in adjacent serial sections. TRPC3 expression was markedly increased in AD cortex and hippocampus whereas TRPC6 was significantly reduced primarily in pyramidal neurons. TRPC3‐positive regions showed close spatial correspondence with reactive astrocytes, particularly in the hippocampal and subcortical white matter regions, suggesting a partial astrocytic origin. TRPC6 exhibited negligible overlap with GFAP. These observations were reproduced in brain sections of both 5xFAD and PS19 transgenic (Tg) mice compared to their littermate controls. Our findings reveal a conserved pattern of divergent TRPC remodeling across human and mouse models with AD pathology. In addition, TRPC1 expression was significantly reduced in AD samples while TRPC4 and TRPC5 had no significant change in expression. Taken together, selected TRPC family members may undergo differential remodeling during AD pathogenesis, with TRPC3 and TRPC6 showing the most prominent and consistent alterations.

The FGF receptors (FGFRs) belong to a family of receptor tyrosine kinases. Abundant evidence shows that FGFRs are closely related to tumor cell invasion and angiogenesis. Hence, targeted modulation... Graphical abstract