Precision Technique for Splenectomy Limits Mouse Stress Responses for Accurate and Realistic Measurements for Investigating Inflammation and Immunity

Electroacupuncture alleviates intestinal inflammation via a distinct neuro-immune signal pathway in the treatment of postoperative ileus

BACKGROUND

The induction of intestinal inflammation as a result of abdominal surgery is an essential factor in postoperative ileus (POI) development. Electroacupuncture (EA) at ST36 has been demonstrated to relieve intestinal inflammation and restore gastrointestinal dysmotility in POI. This study aims to elucidate the neuroimmune pathway involved in the anti-inflammatory properties of EA in POI.

METHODS

After intestinal manipulation (IM) was performed to induce POI, intestinal inflammation and motility were assessed 24 h post-IM, by evaluating gastrointestinal transit (GIT), cytokines expression, and leukocyte infiltration. Experimental surgery, pharmacological intervention, and genetic knockout mice were used to elucidate the neuroimmune mechanisms of EA.

RESULTS

EA at ST36 significantly improved GIT and reduced the expression of pro-inflammatory cytokines and leukocyte infiltration in the intestinal muscularis following IM in mice. The anti-inflammatory effectiveness of EA treatment was abolished by sub-diaphragmatic vagotomy, whereas splenectomy did not hinder the anti-inflammatory benefits of EA treatment. The hexamethonium chloride (HEX) administration contributes to a notable reduction in the EA capacity to suppress inflammation and enhance motility dysfunction, and EA is ineffective in α7 nicotinic acetylcholine receptor (α7nAChR) knockout mice.

CONCLUSIONS

EA at ST36 prevents intestinal inflammation and dysmotility through a neural circuit that requires vagal innervation but is independent of the spleen. Further findings revealed that the process involves enteric neurons mediating the vagal signal and requires the presence of α7nAChR. These findings suggest that utilizing EA at ST36 may represent a possible therapeutic approach for POI and other immune-related gastrointestinal diseases.

An integrated framework for prognosis prediction and drug response modeling in colorectal liver metastasis drug discovery

BACKGROUND

Colorectal cancer (CRC) is the third most prevalent cancer globally, and liver metastasis (CRLM) is the primary cause of death. Hence, it is essential to discover novel prognostic biomarkers and therapeutic drugs for CRLM.

METHODS

This study developed two liver metastasis-associated prognostic signatures based on differentially expressed genes (DEGs) in CRLM. Additionally, we employed an interpretable deep learning model utilizing drug sensitivity databases to identify potential therapeutic drugs for high-risk CRLM patients. Subsequently, in vitro and in vivo experiments were performed to verify the efficacy of these compounds.

RESULTS

These two prognostic models exhibited superior performance compared to previously reported ones. Obatoclax, a BCL-2 inhibitor, showed significant differential responses between high and low risk groups classified by prognostic models, and demonstrated remarkable effectiveness in both Transwell assay and CT26 colorectal liver metastasis mouse model.

CONCLUSIONS

This study highlights the significance of developing specialized prognostication approaches and investigating effective therapeutic drugs for patients with CRLM. The application of a deep learning drug response model provides a new drug discovery strategy for translational medicine in precision oncology.

Ticagrelor regulates the differentiation of MDSCs after acute myocardial infarction to reduce cardiac injury

Myeloid-derived suppressor cells (MDSCs) are important participants after acute myocardial infarction (AMI), but the role of their different subtypes in AMI remains controversial. The anti-inflammatory effect of ticagrelor in AMI has been discovered. However, the detailed anti-inflammatory mechanism has not been fully demonstrated. In this study, we aimed to determine whether ticagrelor can regulate the differentiation of MDSCs into anti-inflammatory subgroups to exert anti-inflammatory effects after AMI. In vitro experiments revealed no difference in the mRNA and protein expression of P2Y12 receptors on MDSCs and macrophages. Ticagrelor promotes the differentiation of in vitro cultured MDSCs to monocytic-MDSCs (M-MDSCs). A mouse AMI model was established to investigate the anti-inflammatory effects of ticagrelor in vivo after AMI by interfering with the differentiation of MDSCs. On the first day after AMI, spleen-derived polymorphonuclear-MDSCs (PMN-MDSCs) were predominant in the circulation and infarcted heart. Ticagrelor increased the percentage of M-MDSCs in the circulation and infarcted heart of AMI mice in a dose-dependent manner, attenuated cardiac inflammation and increased cardiac contractile function. M-MDSC injection significantly decreased cardiac inflammation levels and improved cardiac function in splenectomized AMI mice compared with PMN-MDSC injection. These data point to a novel anti-inflammatory role for ticagrelor after AMI by interfering with the differentiation of MDSCs.

Blocking the A2B adenosine receptor alleviates myocardial damage by inhibiting spleen-derived MDSC mobilisation after acute myocardial infarction

BACKGROUND

Myeloid-derived suppressor cell (MDSC) mobilisation is an important immune event in acute myocardial infarction (AMI). The A_2B adenosine receptor (A_2BAR) plays key role in regulating MDSC function, but its specific involvement in MDSC mobilisation in AMI remains unclear.

METHODS

In AMI patients, the circulating MDSC ratio and A_2BAR mRNA expression were measured. A mouse AMI model was established by left anterior descending coronary artery (LADCA) ligation. MDSCs were analysed by FACS and immunofluorescence staining (of heart tissue). A_2BAR mRNA expression was assessed by qRT-PCR. Myocardial injury was detected by HE staining. Myocardial cell apoptosis was analysed by immunohistochemistry. Cardiac systolic function was evaluated by transthoracic echocardiography.

RESULTS

In AMI patients, the circulating MDSC ratio was increased and positively correlated with A_2BAR mRNA expression (r = 0.86, p < 0.01). In AMI model mice, the percentage of MDSCs was increased in the circulation and infarcted heart and decreased in the spleen. MRS-1754-mediated A_2BAR inhibition decreased the MDSC ratio in the circulation and infarcted heart and prevented the decrease in MDSC number in the spleens of mice with AMI. A_2BAR blockade inhibited myocardial cell apoptosis, alleviated myocardial inflammatory injury, and improved myocardial systolic function in the AMI mouse model. Similar results were found in mice after splenectomy. Additionally, spleen-derived MDSC injection increased the MDSC ratio in the infarcted heart, increased myocardial cell apoptosis, aggravated myocardial injury, and decreased cardiac systolic function in mice with AMI.

CONCLUSION

Blocking A_2BAR alleviates myocardial damage and improves myocardial systolic function through inhibition of spleen-derived MDSC mobilisation after AMI. Key MessagesSpleen-derived MDSC mobilisation aggravates myocardial inflammatory injury within 24 h of AMI.A_2BAR promotes spleen-derived MDSC mobilisation within 24 h of AMI.Blocking A_2BAR improves myocardial systolic function through inhibition of spleen-derived MDSC mobilisation.

Chlamydia spreads to the large intestine lumen via multiple pathways

Chlamydia in the genital tract is known to spread via the blood circulation system to the large intestinal lumen to achieve long-lasting colonization. However, the precise pathways for genital Chlamydia to access to the large intestinal lumen remain unclear. The spleen was recently reported to be critical for the chlamydial spreading. In the current study, it was found that following intravaginal inoculation with Chlamydia, mice with or without splenectomy both produced infectious Chlamydia in the rectal swabs, indicating that spleen is not essential for genital Chlamydia to spread to the gastrointestinal tract. This conclusion was validated by the observation that intravenously inoculated Chlamydia was also detected in the rectal swabs of mice regardless of splenectomy. Careful comparison of the tissue distribution of live chlamydial organisms following intravenous inoculation revealed redundant pathways for Chlamydia to reach the large intestine lumen. The intravenously inoculated Chlamydia was predominantly recruited to the spleen within 12h and then detected in the stomach lumen by 24h, the intestinal lumen by 48h and rectal swabs by 72h. These observations suggest a potential spleen-to-stomach pathway for hematogenous Chlamydia to reach the large intestine lumen. This conclusion was supported by the observation made in mice under coprophagy-free condition. However, in the absence of spleen, hematogenous Chlamydia was predominantly recruited to the liver and then simultaneously detected in the intestinal tissue and lumen, suggesting a potential liver-to-intestine pathway for Chlamydia to reach the large intestine lumen. Thus, genital/hematogenous Chlamydia may reach the large intestinal lumen via multiple redundant pathways.

Autologous Splenocyte Reinfusion Improves Antibody-Mediated Immune Response to the 23-Valent Pneumococcal Polysaccharide-Based Vaccine in Splenectomized Mice

Common clinical options, currently, for necessary splenectomy are vaccinations and antibiotic prophylaxis. However, despite these two adjuncts, there still occur numerous cases of overwhelming post-splenectomy infection. To examine whether reperfusion of critical splenic lymphocytes could boost immune response, we harvested splenic lymphocytes, reperfused the autologous lymphocytes, and then administered a pneumococcal vaccine (PNEUMOVAX^®23, i.e., PPSV23) in splenectomized mice. We found that splenectomy impaired the immune response in the splenectomized group compared to the non-splenectomized group; the splenectomized group with lymphocyte reinfusion had a higher response to polysaccharide vaccination based on antibody titer than the splenectomized group without lymphocyte reinfusion. The sham group with the native spleen had the most elevated antibody titer against the PPSV23 polysaccharide antigen. This may be additive, resulting from contributions of the splenic structure, along with the phagocytic function of the spleen and its constituent cells affecting the antibody response. Reinfusion of splenic lymphocytes may enhance immunity without the complications associated with splenic fragment autotransplantation, which never gained acceptance. This technique is safe and simple since the splenic lymphocytes are autologous and, therefore, not self-reactive, and very similar to autologous blood transfusion. This concept may be beneficial in cases of unavoidable splenectomy, especially in pediatric cases.