Journal of Biomedical Science (May 2024)

Targeting cathepsin S promotes activation of OLF1-BDNF/TrkB axis to enhance cognitive function

  • Hao-Wei Lee,
  • Szu-Jung Chen,
  • Kuen-Jer Tsai,
  • Kuei-Sen Hsu,
  • Yi-Fan Chen,
  • Chih-Hua Chang,
  • Hsiao-Han Lin,
  • Wen-Yun Hsueh,
  • Hsing-Pang Hsieh,
  • Yueh-Feng Lee,
  • Huai-Chueh Chiang,
  • Jang-Yang Chang

DOI
https://doi.org/10.1186/s12929-024-01037-2
Journal volume & issue
Vol. 31, no. 1
pp. 1 – 23

Abstract

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Abstract Background Cathepsin S (CTSS) is a cysteine protease that played diverse roles in immunity, tumor metastasis, aging and other pathological alterations. At the cellular level, increased CTSS levels have been associated with the secretion of pro-inflammatory cytokines and disrupted the homeostasis of Ca2+ flux. Once CTSS was suppressed, elevated levels of anti-inflammatory cytokines and changes of Ca2+ influx were observed. These findings have inspired us to explore the potential role of CTSS on cognitive functions. Methods We conducted classic Y-maze and Barnes Maze tests to assess the spatial and working memory of Ctss −/− mice, Ctss +/+ mice and Ctss +/+ mice injected with the CTSS inhibitor (RJW-58). Ex vivo analyses including long-term potentiation (LTP), Golgi staining, immunofluorescence staining of sectioned whole brain tissues obtained from experimental animals were conducted. Furthermore, molecular studies were carried out using cultured HT-22 cell line and primary cortical neurons that treated with RJW-58 to comprehensively assess the gene and protein expressions. Results Our findings reported that targeting cathepsin S (CTSS) yields improvements in cognitive function, enhancing both working and spatial memory in behavior models. Ex vivo studies showed elevated levels of long-term potentiation levels and increased synaptic complexity. Microarray analysis demonstrated that brain-derived neurotrophic factor (BDNF) was upregulated when CTSS was knocked down by using siRNA. Moreover, the pharmacological blockade of the CTSS enzymatic activity promoted BDNF expression in a dose- and time-dependent manner. Notably, the inhibition of CTSS was associated with increased neurogenesis in the murine dentate gyrus. These results suggested a promising role of CTSS modulation in cognitive enhancement and neurogenesis. Conclusion Our findings suggest a critical role of CTSS in the regulation of cognitive function by modulating the Ca2+ influx, leading to enhanced activation of the BDNF/TrkB axis. Our study may provide a novel strategy for improving cognitive function by targeting CTSS.

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