Shinjiro Hino

It is well‐established that spinal microglia and peripheral macrophages play critical roles in the etiology of neuropathic pain; however, growing evidence suggests sex differences in pain hypersensitivity owing to microglia and macrophages. Therefore, it is crucial to understand sex‐ and androgen‐dependent characteristics of pain‐related myeloid cells in mice with nerve injury‐induced neuropathic pain. To deplete microglia and macrophages, pexidartinib (PLX3397), an inhibitor of the colony‐stimulating factor 1 receptor, was orally administered, and mice were subjected to partial sciatic nerve ligation (PSL). Following PSL induction, healthy male and female mice and male gonadectomized (GDX) mice exhibited similar levels of spinal microglial activation, peripheral macrophage accumulation, and mechanical allodynia. Treatment with PLX3397 significantly suppressed mechanical allodynia in normal males; this was not observed in female and GDX male mice. Sex‐ and androgen‐dependent differences in the PLX3397‐mediated preventive effects were observed on spinal microglia and dorsal root ganglia (DRG) macrophages, as well as in expression patterns of pain‐related inflammatory mediators in these cells. Conversely, no sex‐ or androgen‐dependent differences were detected in sciatic nerve macrophages, and inhibition of peripheral CC‐chemokine receptor 5 prevented neuropathic pain in both sexes. Collectively, these findings demonstrate the presence of considerable sex‐ and androgen‐dependent differences in the etiology of neuropathic pain in spinal microglia and DRG macrophages but not in sciatic nerve macrophages. Given that the mechanisms of neuropathic pain may differ among experimental models and clinical conditions, accumulating several lines of evidence is crucial to comprehensively clarifying the sex‐dependent regulatory mechanisms of pain.

The high glycolytic activity of cancer cells leads to lactic acidosis (LA) in the tumor microenvironment. LA is not merely a consequence of metabolic activities but also has functional roles in metabolic reprogramming and cancer progression. Cholangiocarcinoma (CCA) cells exhibit a high dependency on glycolysis for survival and growth, but the specific effects of LA on cellular characteristics remain unknown. Here, we demonstrate that long‐term LA (LLA) reprograms the metabolic phenotype of CCA cells from glycolytic to oxidative and enhances their migratory activity. In CCA cell culture, short‐term LA (24 h) showed a growth inhibitory effect, while extended LA exposure for more than 2 weeks (LLA) led to enhanced cell motility. Coincidentally, LLA enhanced the respiratory capacity with an increase in mitochondrial mass. Inhibition of mitochondrial function abolished LLA‐induced cell motility, suggesting that metabolic remodeling affects the phenotypic outcomes. RNA‐sequencing analysis revealed that LLA upregulated genes associated with cell migration and epithelial–mesenchymal transition (EMT), including thrombospondin‐1 ( THBS1 ), which encodes a pro‐EMT‐secreted protein. Inhibition of THBS1 resulted in the suppression of both LLA‐induced cell motility and respiratory capacity. Moreover, high THBS1 expression was associated with poor survival in patients with CCA. Collectively, our study suggests that the increased expression of THBS1 by LLA promotes phenotypic alterations, leading to CCA progression.