Colorectal carcinoma (CRC) is a malignant tumor of the digestive system. Cancer-associated fibroblasts (CAFs) are important cellular elements in the tumor microenvironment of CRC, which contribute to CRC progression and immune escape. To predict the survival outcome and therapeutic responses of CRC patients, we identified genes connected with stromal CAF and generated a risk model. In this study, we used multiple algorithms to reveal CAF-related genes in the Gene Expression Omnibus and The Cancer Genome Atlas datasets and construct a risk model composed by prognostic CAF-associated genes. Then, we evaluated whether the risk score could predict CAF infiltrations and immunotherapy in CRC and confirmed the expression of the risk model in CAFs. Our results showed that CRC patients with high CAF infiltrations and stromal score had worse prognosis than those with low-CAF infiltrations and stromal score. We obtained 88 stromal CAF-associated hub-genes and generated a CAF risk model consisting of ZNF532 and COLEC12. Compared with low-risk group, the overall survival in high-risk group was shorter. The relationship between risk score, ZNF532 and COLEC12, and stromal CAF infiltrations and CAF markers was positive. In addition, the effect of immunotherapy in the high-risk group was not as good as that in the low-risk group. Patients with the high-risk group were enriched in chemokine signaling pathway, cytokine-cytokine receptor interaction, and focal adhesion. Finally, we confirmed that the expressions of ZNF532 and COLEC12 in risk model were widely distributed in fibroblasts of CRC, and the expression levels were higher in fibroblasts than CRC cells. In conclusion, the prognostic CAF signature of ZNF532 and COLEC12 can be applied not only to predict the prognosis of CRC patients but also to evaluate the immunotherapy response in CRC patients, and these findings provide the possibility for further development of individualized treatment for CRC.

Enhanced glycolysis contributes to the chemotherapy resistance of colorectal cancer (CRC). However, whether tRNA-derived small RNAs (tsRNAs) regulate CRC oxaliplatin sensitivity through glycolysis-mediated histone lactylation remains unclear. By analyzing RNA-seq data from CRC samples in the TCGA database, we identified a glucose metabolism-related tsRNA. Overexpression of tsRNA-08614 was investigated to explore its impact on CRC sensitivity to oxaliplatin. The targeting gene of tsRNA-08614 was validated through a dual-luciferase reporter assay. The specific molecular mechanism of tsRNA-08614 regulating CRC oxaliplatin sensitivity was further revealed by ChIP-seq and RNA-seq. We found a down-regulated tsRNA-08614 targeted glycolysis-related gene, which was associated with chemotherapy resistance. Overexpression of tsRNA-08614 promoted oxaliplatin sensitivity of CRC cells. tsRNA-08614 inhibited the expression of the target gene ALDH1A3 and reduced glycolysis, whereas the glycolytic inducer reversed the enhanced sensitivity caused by tsRNA-08614. Interference of tsRNA-08614 increased H3K18la and pan-Kla levels, while the lactate inhibitor partially suppressed these effects. Furthermore, overexpression of tsRNA-08614 reprogrammed the transcription of genes mediated by histone lactylation modification, with EFHD2 showing the most significant differential expression. EFHD2 inhibited the sensitivity of CRC cells to oxaliplatin by upregulating CMPK2 and enhancing mitochondrial function. Finally, we demonstrated that tsRNA-08614 enhanced sensitivity to oxaliplatin in CRC by reducing histone lactylation levels in vivo. tsRNA-08614 regulates ALDH1A3 to inhibit glycolysis and histone lactylation modification, thereby suppressing the transcriptional activity of EFHD2 and ultimately promoting the sensitivity of CRC to oxaliplatin. These findings suggest that tsRNA-08614 may represent a novel molecular target to combat oxaliplatin resistance in CRC chemotherapy.

Physical symptoms and aversion induced by opioid withdrawal strongly affect the management of opioid addiction. YTH N6-methyladenosine (m6A) RNA binding protein 1 (YTHDF1), an m6A-binding protein, from the periaqueductal gray (PAG) reportedly contributes to morphine tolerance and hyperalgesia. However, the role of YTHDF1 in morphine withdrawal remains unclear. A naloxone-precipitated morphine withdrawal model was established in C57/BL6 mice or transgenic mice. YTHDF1 was knocked down via adeno-associated virus transfection. Combined with the results of the single-cell RNA sequencing analysis, the changes in morphine withdrawal somatic signs and conditioned place aversion (CPA) scores were compared when YTHDF1 originating from different neurons in the ventrolateral periaqueductal gray (vlPAG) was knocked down. We further explored the role of inflammatory factors and transcription factors related to inflammatory response in morphine withdrawal. Our results revealed that YTHDF1 expression was upregulated in the vlPAG of mice with morphine withdrawal and that the knockdown of vlPAG YTHDF1 attenuated morphine withdrawal-related somatic signs and aversion. The levels of NF-κB and p-NF-κB were reduced after the inhibition of YTHDF1 in the vlPAG. YTHDF1 from vlPAG inhibitory neurons, rather than excitatory neurons, facilitated morphine withdrawal responses. The inhibition of YTHDF1 in vlPAG somatostatin (Sst)-expressing neurons relieved somatic signs of morphine withdrawal and aversion, whereas the knockdown of YTHDF1 in cholecystokinin (Cck)-expressing or parvalbumin (PV)-expressing neurons did not change morphine withdrawal-induced responses. The activity of c-fos + neurons, the intensity of the calcium signal, the density of dendritic spines, and the frequency of mIPSCs in the vlPAG, which were increased in mice with morphine withdrawal, were decreased with the inhibition of YTHDF1 from vlPAG inhibitory neurons or Sst-expressing neurons. Knockdown of NF-κB in Sst-expressing neurons also alleviated morphine withdrawal-induced responses. YTHDF1 originating from Sst-expressing neurons in the vlPAG is crucial for the modulation of morphine withdrawal responses, and the underlying mechanism might be related to the regulation of the expression and phosphorylation of NF-κB.