[Establishment of a prediction model for colorectal cancer immune cell infiltration based on the cancer genome atlas (TCGA) database].

OBJECTIVE: To study the correlation between immune cell infiltration in colorectal cancer tissue and clinical prognosis and to explore the levels of some immune cell genes for predicting the prognosis of patients with glioma colorectal cancer. METHODS: In this study, we extracted colorectal cancer data from the cancer genome atlas (TCGA). Based on a deconvolution algorithm (called CIBERSORT) and clinically annotated expression profiles, the analysis assessed the infiltration patterns of 22 immune cells in colorectal cancer tissue to determine the association between each cell type and survival. Differences in five-year survival rate effectively illustrate the clinical prognostic value of each immune cell proportion in colorectal cancer, using a bar graph, correlation-based heatmap to represent the proportion of immune cells in each colorectal cancer sample. RESULTS: A total of 473 colorectal cancer tissues and 41 normal control tissues were extracted from the TCGA database, and the comparative analysis showed that there were differences in the proportion of various TIICs in colorectal cancer tissues, which could characterize individual differences and have prognostic value. Among the cell subsets studied, the proportions of memory B cells, plasma cells, CD4+ T cells, natural killer (NK) cells, M0 macrophages, M2 macrophages, and activated mast cells were significantly different between normal and cancer tissues. Resting NK cells, CD8+ T cells, and plasma cells were associated with T phase, activated dendritic cells were associated with N phase, and eosinophils, M1 macrophages, and activated mast cells were associated with M phase. Survival analysis showed that activated dendritic cells were positively associated with five-year survival rate in colorectal cancer patients. Naive CD4+ T cells were inversely associated with five-year survival rate. CONCLUSION: There are different degrees of immune cell infiltration in colorectal cancer tissues, and these differences may be important determinants of prognosis and treatment response. We conducted a new gene expression-based study of immune cell subtype levels and prognosis in colorectal cancer, which has potential clinical prognostic value in colorectal cancer patients.

Role of TRPV1 and ASIC3 channels in experimental occlusal interference-induced hyperalgesia in rat masseter muscle.

BACKGROUND: Masticatory muscle pain may occur following immediate occlusal alteration by dental treatment. The underlying mechanisms are poorly understood. Transient receptor potential vanilloid-1 (TRPV1) and acid-sensing ion channel-3 (ASIC3) mediate muscle hyperalgesia under various pathologic conditions. We have developed a rat model of experimental occlusal interference (EOI) that consistently induces mechanical hyperalgesia in jaw muscles. Whether TRPV1 and ASIC3 mediate this EOI-induced hyperalgesia is unknown. METHODS: Rat model of EOI-induced masseter hyperalgesia was established. Real-time polymerase chain reaction, Western blot and retrograde labelling combined with immunofluorescence were performed to evaluate the modulation of TRPV1 and ASIC3 expression in trigeminal ganglia (TGs) and masseter afferents of rats after EOI. The effects of intramuscular administration of TRPV1 and ASIC3 antagonists on the EOI-induced hyperalgesia in masseter muscle were examined. RESULTS: After EOI, gene expressions and protein levels of TRPV1 and ASIC3 in bilateral TGs were up-regulated. The percentage of ASIC3- (but not TRPV1-) positive neurons in masseter afferents increased after EOI. More small-sized and small to medium-sized masseter afferents expressed TRPV1 and ASIC3 separately following EOI. These changes peaked at day 7 and then returned to original status within 10 days after EOI. Intramuscular administration of the TRPV1 antagonist AMG-9810 partially reversed this mechanical hyperalgesia in masseter muscle. No improvement was exhibited after administration of the ASIC3 antagonist APETx2. Co-injection of AMG-9810 and APETx2 enhanced the effect of AMG-9810 administration alone. CONCLUSIONS: Peripheral TRPV1 and ASIC3 contribute to the development of the EOI-induced mechanical hyperalgesia in masseter muscle.

Inflammatory pain memory facilitates occlusal interference-induced masticatory muscle hyperalgesia in rats.

BACKGROUND: Patients with an orofacial pain history appear to be more susceptible to occlusal interference pain in dental practice for unknown reasons. Pain memory has a critical function in subsequent pain perception. This study aims to explore whether orofacial pain memory could affect the masticatory muscle pain perception for occlusal interference. METHODS: Cross-injection of 2% carrageenan into bilateral masseters in male rats was carried out to establish the inflammatory pain memory model. The effects of pain memory on masseter muscle nociception were tested by applying crowns with heights beyond the occlusal plane by 0.2 or 0.4 mm onto a maxillary molar 2 weeks after inflammation in the right masseter. The 0.4-mm crowns were removed on day 2 or day 4 after application to further confirm the effects of pain memory. Moreover, memory impairment was established using ibotenic acid (IBO) infusion into the bilateral hippocampus, followed by behaviour tests, including the Morris water maze test and the locomotor activity test. The relationship between pain memory and occlusal interference-induced masseter muscle pain perception was subsequently re-examined. The head withdrawal thresholds of masseters on both sides were measured to reflect the perception. RESULTS: Inflammatory pain memory aggravated the 0.2-mm crown-induced mechanical hyperalgesia of the masseters, but not in the 0.4-mm crown group. However, the recovery of the 0.4-mm crown-induced mechanical hyperalgesia was postponed. The effects of pain memory were reversed in rats with impaired mnemonic function of the hippocampus. CONCLUSIONS: Inflammatory pain memory facilitated occlusal interference-induced masseter muscle pain.

Vesicle permeabilization by protofibrillar alpha-synuclein: implications for the pathogenesis and treatment of Parkinson's disease.

Fibrillar alpha-synuclein is a component of the Lewy body, the characteristic neuronal inclusion of the Parkinson's disease (PD) brain. Both alpha-synuclein mutations linked to autosomal dominant early-onset forms of PD promote the in vitro conversion of the natively unfolded protein into ordered prefibrillar oligomers, suggesting that these protofibrils, rather than the fibril itself, may induce cell death. We report here that protofibrils differ markedly from fibrils with respect to their interactions with synthetic membranes. Protofibrillar alpha-synuclein, in contrast to the monomeric and the fibrillar forms, binds synthetic vesicles very tightly via a beta-sheet-rich structure and transiently permeabilizes these vesicles. The destruction of vesicular membranes by protofibrillar alpha-synuclein was directly observed by atomic force microscopy. The possibility that the toxicity of alpha-synuclein fibrillization may derive from an oligomeric intermediate, rather than the fibril, has implications regarding the design of therapeutics for PD.

Acceleration of oligomerization, not fibrillization, is a shared property of both alpha-synuclein mutations linked to early-onset Parkinson's disease: implications for pathogenesis and therapy.

The Parkinson's disease (PD) substantia nigra is characterized by the presence of Lewy bodies containing fibrillar alpha-synuclein. Early-onset PD has been linked to two point mutations in the gene that encodes alpha-synuclein, suggesting that disease may arise from accelerated fibrillization. However, the identity of the pathogenic species and its relationship to the alpha-synuclein fibril has not been elucidated. In this in vitro study, the rates of disappearance of monomeric alpha-synuclein and appearance of fibrillar alpha-synuclein were compared for the wild-type (WT) and two mutant proteins, as well as equimolar mixtures that may model the heterozygous PD patients. Whereas one of the mutant proteins (A53T) and an equimolar mixture of A53T and WT fibrillized more rapidly than WT alpha-synuclein, the other (A30P) and the corresponding equimolar mixture with WT fibrillized more slowly. However, under conditions that ultimately produced fibrils, the A30P monomer was consumed at a comparable rate or slightly more rapidly than the WT monomer, whereas A53T was consumed even more rapidly. The difference between these trends suggested the existence of nonfibrillar alpha-synuclein oligomers, some of which were separated from fibrillar and monomeric alpha-synuclein by sedimentation followed by gel-filtration chromatography. Spheres (range of heights: 2-6 nm), chains of spheres (protofibrils), and rings resembling circularized protofibrils (height: ca. 4 nm) were distinguished from fibrils (height: ca. 8 nm) by atomic force microscopy. Importantly, drug candidates that inhibit alpha-synuclein fibrillization but do not block its oligomerization could mimic the A30P mutation and thus may accelerate disease progression.