Shared and unique therapeutic targets of KarXT and clozapine for schizophrenia treatment revealed by network pharmacology and molecular docking analyses: Implications for differential clinical responses

Xanomeline plus trospium (KarXT) is a combination drug targeting muscarinic receptors with demonstrated efficacy against positive, negative, and cognitive symptoms of schizophrenia, although therapeutic effects on positive and negative symptoms do not differ significantly from risperidone and olanzapine. Clozapine remains the most effective treatment for schizophrenia unresponsive to other antipsychotics and demonstrates superior efficacy for positive and negative symptoms compared to risperidone and olanzapine. However, the common and distinct molecular targets underlying these different clinical responses to KarXT and clozapine are not fully understood. Potential xanomeline and clozapine targets were identified by searching PharmMapper, SwissTargetPrediction, GeneCards, and SuperPred, and schizophrenia-related targets by searching GeneCards, OMIM, and TTD. Protein-protein interaction (PPI) networks were constructed to identify hub targets, and GO and KEGG pathway enrichment analyses were conducted for the top 25 targets using DAVID. Cytoscape was used to build a network linking drugs, pathways, targets, and disease. Molecular docking simulations were conducted to assess drug binding affinities to core targets. Combined database searches identified 103 overlapping targets for xanomeline and schizophrenia, and 285 overlapping targets for clozapine and schizophrenia. PPI network and KEGG pathway analyses identified FOS, CASP3, NFKB1, AKT1, IGF1, KDR, and CDC42, proteins related to apoptosis, inflammation, neuroprotection, and MAPK signaling, as core xanomeline targets, and FOS, CASP3, NFKB1, TNF, IL6, IFNG, and CXCL8, proteins involved in apoptosis, inflammation, immune responses, and IL-17 signaling, as core clozapine targets. Molecular docking confirmed strong binding between drugs and core targets. KarXT and clozapine share core targets FOS, CASP3, and NFKB1. Distinct KarXT targets such as AKT1, IGF1, KDR, and CDC42, and clozapine targets including TNF, IL6, IFNG, and CXCL8 may explain differences in therapeutic efficacy. These bioinformatics findings support recent meta-analyses and provide guidance for more appropriate drug selection.