Profiling Humoral Immunity After Mixing and Matching COVID-19 Vaccines Using SARS-CoV-2 Variant Protein Microarrays.

In November 2022, 68% of the population received at least one dose of COVID-19 vaccines. Owing to the ongoing mutations, especially for the variants of concern (VOCs), it is important to monitor the humoral immune responses after different vaccination strategies. In this study, we developed a SARS-CoV-2 variant protein microarray that contained the spike proteins from the VOCs, e.g., alpha, beta, gamma, delta, and omicron, to quantify the binding antibody and surrogate neutralizing antibody. Plasmas were collected after two doses of matching AZD1222 (AZx2), two doses of matching mRNA-1273 (Mx2), or mixing AZD1222 and mRNA-1273 (AZ+M). The results showed a significant decrease of surrogate neutralizing antibodies against the receptor-binding domain in all VOCs in AZx2 and Mx2 but not AZ+M. A similar but minor reduction pattern of surrogate neutralizing antibodies against the extracellular domain was observed. While Mx2 exhibited a higher surrogate neutralizing level against all VOCs compared with AZx2, AZ+M showed an even higher surrogate neutralizing level in gamma and omicron compared with Mx2. It is worth noting that the binding antibody displayed a low correlation to the surrogate neutralizing antibody (R-square 0.130-0.382). This study delivers insights into humoral immunities, SARS-CoV-2 mutations, and mixing and matching vaccine strategies, which may provide a more effective vaccine strategy especially in preventing omicron.

Relationship between social participation and depressive symptoms in patients with multimorbidity: the chained mediating role of cognitive function and activities of daily living.

OBJECTIVE: The potential mechanisms linking social participation and depressive symptoms in Chinese individuals with multimorbidity are not yet fully understood. This study aims to explore how cognitive function and activities of daily living (ADLs) mediate the relationship between social participation and depressive symptoms in individuals with multimorbidity. METHODS: We selected 3782 participants with multimorbidity from the 2018 China Health and Retirement Longitudinal Study. Data related to social participation, cognitive function, ADLs, and depressive symptoms were extracted. Regression and Bootstrap analyses were used to explore the sequential mediating effects of social participation, cognitive function, ADLs, and depressive symptoms. RESULTS: (1) There was a significant correlation between social participation, cognitive function, activities of daily living, and depressive symptoms (p < 0.01). (2) Social participation directly affected depressive symptoms (ß = -0.205, p < 0.05). (3) Cognitive function (ß = -0.070, p < 0.01) and activities of daily living (ß = -0.058, p < 0.01) played separate mediating roles in the effect of social participation on depressive symptoms. (4) Cognitive function and activities of daily living had a chain-mediated role in the relationship between social participation and depressive symptoms in patients with multimorbidity (ß = -0.020, p < 0.01). CONCLUSION: A chained mediating effect was found between cognitive function, ADLs, social participation, and depressive symptoms in patients with multimorbidity. Social participation was found to improve the cognitive function of patients with multimorbidity, which in turn enhanced their daily life activities and ultimately alleviated their depressive symptoms.

Metformin abrogates Fusobacterium nucleatum-induced chemoresistance in colorectal cancer by inhibiting miR-361-5p/sonic hedgehog signaling-regulated stemness.

BACKGROUND: Chemotherapy resistance is the major cause of recurrence in patients with colorectal cancer (CRC). A previous study found that Fusobacterium (F.) nucleatum promoted CRC chemoresistance. Additionally, metformin rescued F. nucleatum-induced tumorigenicity of CRC. Here, we aimed to investigate whether metformin could revert F. nucleatum-induced chemoresistance and explore the mechanism. METHODS: The role of metformin in F. nucleatum-infected CRC cells was confirmed using cell counting kit 8 assays and CRC xenograft mice. Stemness was identified by tumorsphere formation. Bioinformatic analyses were used to explore the regulatory molecules involved in metformin and F. nucleatum-mediated regulation of the sonic hedgehog pathway. RESULTS: We found that metformin abrogated F. nucleatum-promoted CRC resistance to chemotherapy. Furthermore, metformin attenuated F. nucleatum-stimulated stemness by inhibiting sonic hedgehog signaling. Mechanistically, metformin diminished sonic hedgehog signaling proteins by targeting the MYC/miR-361-5p cascade to reverse F. nucleatum-induced stemness, thereby rescuing F. nucleatum-triggered chemoresistance in CRC. CONCLUSIONS: Metformin acts on F. nucleatum-infected CRC via the MYC/miR-361-5p/sonic hedgehog pathway cascade, subsequently reversing stemness and abolishing F. nucleatum-triggered chemoresistance. Our results identified metformin intervention as a potential clinical treatment for patients with chemoresistant CRC with high amounts of F. nucleatum.

Antibody Profiling of Dengue Severities Using Flavivirus Protein Microarrays.

Dengue is a viral disease transmitted by Aedes aegypti mosquitoes. According to the World Health Organization, about half of the world's population is at risk of dengue. There are four serotypes of the dengue virus. After infection with one serotype, it will be immune to such a serotype. However, subsequent infection with other serotypes will increase the risk of severe outcomes, e.g., dengue hemorrhagic fever, dengue shock syndrome, and even death. Since severe dengue is challenging to predict and lacks molecular markers, we aim to build a multiplexed Flavivirus protein microarray (Flaviarray) that includes all of the common Flaviviruses to profile the humoral immunity and cross-reactivity in the dengue patients with different outcomes. The Flaviarrays we fabricated contained 17 Flavivirus antigens with high reproducibility (R-square = 0.96) and low detection limits (172-214 pg). We collected serums from healthy subjects (n = 36) and dengue patients within 7 days after symptom onset (mild dengue (n = 21), hospitalized nonsevere dengue (n = 29), and severe dengue (n = 36)). After profiling the serum antibodies using Flaviarrays, we found that patients with severe dengue showed higher IgG levels against multiple Flavivirus antigens. With logistic regression, we found groups of markers with high performance in distinguishing dengue patients from healthy controls as well as hospitalized from mild cases (AUC > 0.9). We further reported some single markers that were suitable to separate dengue patients from healthy controls (AUC > 0.9) and hospitalized from mild outcomes (AUC > 0.8). Together, Flaviarray is a valuable tool to profile antibody specificities, uncover novel markers for decision-making, and shed some light on early preventions and treatments.

Intravenous metronidazole-, levofloxacin-containing triple therapy for treating patients with Helicobacter pylori-related active peptic ulcer complications: A pilot study.

OBJECTIVE: The aim of this pilot study was to evaluate the efficacy and safety of intravenous use esomeprazole, metronidazole, and/or levofloxacin in the treatment of Helicobacter pylori (H. pylori)-associated peptic ulcer complications. METHODS: Inpatients with peptic ulcer complications who were not able to take oral medicine were randomly assigned to three groups: triple therapy (esomeprazole, levofloxacin, metronidazole) and dual therapy (esomeprazole, levofloxacin/metronidazole) for 7 days. After intravenous treatment, all patients received open-label oral esomeprazole 20 mg bid for another 1 month. All subjects were followed up for gastroscopy at the seventh day of intravenous treatment to confirm the ulcer healing and 13 C-urea breath test to confirm successful H. pylori eradication 4-6 weeks after completion of oral esomeprazole therapy. RESULTS: The H. pylori eradication rate of both LEV-dual therapy (33.3%, 95% CI: 9.7%-70.0%) and MTZ-dual therapy (50%, 95% CI: 21.5%-78.5%) was significantly lower than that of triple therapy (95%, 95% CI: 71.1%-97.4%) (p = .003, .016). There were no significant differences in the adverse effects among all treatment groups, and the adverse effects were rare. CONCLUSIONS: The intravenous triple regimen, consisting of proton-pump inhibitor, metronidazole, and levofloxacin, could be considered in patients of H. pylori-associated peptic ulcer complications if oral medicine cannot be provided.

Profiling humoral responses to COVID-19 immunization in Kawasaki disease using SARS-CoV-2 variant protein microarrays.

Kawasaki disease (KD) is a form of acute systemic vasculitis syndrome that predominantly occurs in children under the age of 5 years. Its etiology has been postulated due to not only genetic factors but also the presence of foreign antigens or infectious agents. To evaluate possible associations between Kawasaki disease (KD) and COVID-19, we investigated humoral responses of KD patients against S-protein variants with SARS-CoV-2 variant protein microarrays. In this study, plasma from a cohort of KD (N = 90) and non-KD control (non-KD) (N = 69) subjects in categories of unvaccinated-uninfected (pre-pandemic), SARS-CoV-2 infected (10-100 days after infection), and 1-dose, 2-dose, and 3-dose BNT162b2 vaccinated (10-100 days after vaccination) was collected. The principal outcomes were non-KD-KD differences for each category in terms of anti-human/anti-His for binding antibodies and neutralizing percentage for surrogate neutralizing antibodies. Binding antibodies against spikes were lower in the KD subjects with 1-dose of BNT162b2, and mean differences were significant for the P.1 S-protein (non-KD-KD, 3401; 95% CI, 289.0 to 6512; P = 0.0252), B.1.617.2 S-protein (non-KD-KD, 4652; 95% CI, 215.8 to 9087; P = 0.0351) and B.1.617.3 S-protein (non-KD-KD, 4874; 95% CI, 31.41 to 9716; P = 0.0477). Neutralizing antibodies against spikes were higher in the KD subjects with 1-dose of BNT162b2, and mean percentage differences were significant for the 1-dose BNT162b2 B.1.617.3 S-protein (non-KD-KD, -22.89%; 95% CI, -45.08 to -0.6965; P = 0.0399), B.1.1.529 S-protein (non-KD-KD, -25.96%; 95% CI, -50.53 to -1.376; P = 0.0333), BA.2.12.1 S-protein (non-KD-KD, -27.83%; 95% CI, -52.55 to -3.115; P = 0.0195), BA.4 S-protein (non-KD-KD, -28.47%; 95% CI, -53.59 to -3.342; P = 0.0184), and BA.5 S-protein (non-KD-KD, -30.42%; 95% CI, -54.98 to -5.869; P = 0.0077). In conclusion, we have found that KD patients have a comparable immunization response to healthy individuals to SARS-CoV-2 infection and COVID-19 immunization.

Antibody Profiling in COVID-19 Patients with Different Severities by Using Spike Variant Protein Microarrays.

The disease progression of COVID-19 varies from mild to severe, even death. However, the link between COVID-19 severities and humoral immune specificities is not clear. Here, we developed a multiplexed spike variant protein microarray (SVPM) and utilized it for quantifying neutralizing activity, drug screening, and profiling humoral immunity. First, we demonstrated the competition between antispike antibody and ACE2 on SVPM for measuring the neutralizing activity against multiple spike variants. Next, we collected the serums from healthy subjects and COVID-19 patients with different severities and profile the neutralizing activity as well as antibody isotypes. We identified the inhibition of ACE2 binding was stronger against multiple variants in severe compared to mild/moderate or critical patients. Moreover, the serum IgG against nonstructural protein 3 was elevated in severe but not in mild/moderate and critical cases. Finally, we evaluated two ACE2 inhibitors, Ramipril and Perindopril, and found the dose-dependent inhibition of ACE2 binding to all the spike variants except for B.1.617.3. Together, the SVPM and the assay procedures provide a tool for profiling neutralizing antibodies, antibody isotypes, and reagent specificities.

γδ T Cells Promote Steatohepatitis by Orchestrating Innate and Adaptive Immune Programming.

BACKGROUND AND AIMS: The recruitment and activation of inflammatory cells in the liver delineates the transition from hepatic steatosis to steatohepatitis (SH). APPROACH AND RESULTS: We found that in SH, γδT cells are recruited to the liver by C-C chemokine receptor (CCR) 2, CCR5, and nucleotide-binding oligomerization domain-containing protein 2 signaling and are skewed toward an interleukin (IL)-17A+ phenotype in an inducible costimulator (ICOS)/ICOS ligand-dependent manner. γδT cells exhibit a distinct Vγ4+ , PD1+ , Ly6C+ CD44+ phenotype in SH. Moreover, γδT cells up-regulate both CD1d, which is necessary for lipid-based antigens presentation, and the free fatty acid receptor, CD36. γδT cells are stimulated to express IL-17A by palmitic acid and CD1d ligation. Deletion, depletion, and targeted interruption of γδT cell recruitment protects against diet-induced SH and accelerates disease resolution. CONCLUSIONS: We demonstrate that hepatic γδT cells exacerbate SH, independent of IL-17 expression, by mitigating conventional CD4+ T-cell expansion and modulating their inflammatory program by CD1d-dependent vascular endothelial growth factor expression.

Comparative Analysis of Chemical Constituents in Different Parts of Lotus by UPLC and QToF-MS.

Six parts of lotus (seeds, leaves, plumule, stamens, receptacles and rhizome nodes) are herbal medicines that are listed in the Chinese Pharmacopoeia. Their indications and functions have been confirmed by a long history of clinical practice. To fully understand the material basis of clinical applications, UPLC-QToF-MS combined with the UNIFI platform and multivariate statistical analysis was used in this study. As a result, a total of 171 compounds were detected and characterized from the six parts, and 23 robust biomarkers were discovered. The method can be used as a standard protocol for the direct identification and prediction of the six parts of lotus. Meanwhile, these discoveries are valuable for improving the quality control method of herbal medicines. Most importantly, this was the first time that alkaloids were detected in the stamen, and terpenoids were detected in the cored seed. The stamen is a noteworthy part because it contains the greatest diversity of flavonoids and terpenoids, but research on the stamen is rather limited.

SRSF3 functions as an oncogene in colorectal cancer by regulating the expression of ArhGAP30.

BACKGROUND: Splicing factor SRSF3 is an oncogene and overexpressed in various kinds of cancers, however, the function and mechanism involved in colorectal cancer (CRC) remained unclear. The aim of this study was to explore the relationship between SRSF3 and carcinogenesis and progression of CRC. METHODS: The expression of SRSF3 in CRC tissues was detected by immunohistochemistry. The proliferation and invasion rate was analyzed by CCK-8 assay, colony formation assay, transwell invasion assay and xenograft experiment. The expression of selected genes was detected by western blot or real time PCR. RESULTS: SRSF3 is overexpressed in CRC tissues and its high expression was associated with CRC differentiation, lymph node invasion and AJCC stage. Upregulation of SRSF3 was also associated with shorter overall survival. Knockdown of SRSF3 in CRC cells activated ArhGAP30/Ace-p53 and decreased cell proliferation, migration and survival; while ectopic expression of SRSF3 attenuated ArhGAP30/Ace-p53 and increases cell proliferation, migration and survival. Targeting SRSF3 in xenograft tumors suppressed tumor progression in vivo. CONCLUSIONS: Taken together, our data identify SRSF3 as a regulator for ArhGAP30/Ace-p53 in CRC, and highlight potential prognostic and therapeutic significance of SRSF3 in CRC.

CD24 Overexpression Related to Lymph Node Invasion and Poor Prognosis of Colorectal Cancer.

BACKGROUND: Cluster of differentiation 24 (CD24) has recently been reported as a biomarker for colorectal cancer. However, the clinical and prognostic significance of CD24 in colorectal cancer remains controversial. Therefore, we performed a meta-analysis to clarify this issue. METHODS: A comprehensive literature search was performed using Medline, Embase, Web of Science, and CNKI, and the statistical analysis was conducted using Stata software. RESULTS: A total of thirteen studies including 2,180 cases were included in this meta-analysis. The pooled analysis indicated that CD24 expression was associated with lymph node invasion (RR = 0.71 (negative versus positive), 95% CI = 0.52 - 0.96, p = 0.02, Figure 3), differentiation (RR = 0.81 (well versus poor), 95% CI = 0.67 - 0.99, p = 0.04), and T stage (RR = 0.74 (T1 + T2 versus T3 + T4), 95% CI = 0.65 - 0.85, p = 0.00). The prognosis analysis also suggested CD24 overexpression indicating poorer 5-year OS rate (RR = 0.74, 95% CI = 0.58 - 0.93, p = 0.01) However, CD24 was not associated with other clinicopathological features such as tumor size, tumor grade, distant metastasis, TNM stage and Dukes stage. CONCLUSIONS: Taken together, this meta-analysis suggested that CD24 is an efficient prognostic factor in colorectal cancer.

Upregulation of ASAP3 contributes to colorectal carcinogenesis and indicates poor survival outcome.

The function and clinical implication of ArfGAP with SH3 domain, ankyrin repeat, and PH domain 3 (ASAP3) in colorectal cancer (CRC) remains undefined. In the present study, we showed that the expression level of ASAP3 was dramatically increased in CRC and its upregulation was associated with American Joint Committee on Cancer stage (P < 0.001) and poor prognosis (P = 0.0022). The combination of stage and ASAP3 expression improved the prediction of survival in CRC patients. Suppression of ASAP3 inhibited cell proliferation by inducing G1 phase arrest without influencing apoptosis. ASAP3 promoted growth of colon tumors in mice with colitis, and accelerated cell invasion and migration in vitro. Increased ASAP3 was associated with activation of the nuclear factor-κB (NF-κB) canonical pathway in CRC. Upregulation of ASAP3 increased the phosphorylation and nuclear translocation of the p65 NF-κB subunit. Mechanistically, ASAP3 interacts with NF-κB essential modulator (NEMO) and could reduce the polyubiquitinylation of NEMO. Overall, ASAP3 might regulate NF-κB via binding to NEMO. ASAP3 acts as an oncogene in colonic cancer and could be a potential biomarker of colon carcinogenesis.

A study on the identification of factors related to depression in a population with an increasing number of chronic diseases in the short term in China based on a health ecology model.

BACKGROUND: The rapid increase in the number of patients with chronic diseases and depression, as well as the rapid spread of their effects, have led to these two health problems gradually developing into major public health issues in China and around the world. Currently, many individuals with chronic diseases are experiencing depressive symptoms one after another. Therefore, it is imperative to conduct research on how to prevent depression in this growing population of individuals with chronic diseases in a timely manner. METHODS: Based on the data of the 2015 and 2018 national follow-up surveys of the China Health and Retirement Longitudinal Study, a total of 7641 patients with short-term increase in the number of chronic diseases were selected as the study objects, and a binary logistic regression model was constructed according to the five dimensions of the health ecology model. The neural network model was used to explore the main (first two) factors affecting the increase in the number of chronic diseases in China in the short term, and the random forest and extreme value gradient lifting algorithm were used to verify them, and effective suggestions were put forward. RESULTS: The detection rate of depression in the population with increasing number of chronic diseases from 2015 to 2018 was 42.13 %. The model was established based on five dimensions of the health ecology model: Model 1 (Personal trait layer), Model 2 (Personal trait layer plus Behavioral feature layer), Model 3 (Personal trait layer plus Behavioral feature layer plus Living and working conditions layer), Model 4 (Personal trait layer plus Behavioral feature layer plus Living and working conditions layer plus Networking layer) and Model 5 (Personal trait layer plus Behavioral feature layer plus Living and working conditions layer plus Networking layer plus Policy environment layer).The prediction accuracy of the five models was 66.4 %, 68.3 %, 70.7 %, 71.6 % and 71.6 %, respectively, and Model 5 showed that the P values of gender, self-rated health, night's sleep time (h), disability, life satisfaction, child satisfaction, place of residence and highest level of education were all <0.05, life satisfaction and self-rated health importance were 0.249 (100 %) and 0.226 (90.8 %). CONCLUSION: Gender, self-rated health, night sleep duration, disability, satisfaction with life, satisfaction with children, place of residence and highest level of education were the main influencing factors for the increase of depressive symptoms in the population with chronic diseases in the short term, among which life satisfaction and self-rated health have the greatest impact on depressive symptoms, and there is an interaction between the two.

Enhancing psychological well-being in college students: the mediating role of perceived social support and resilience in coping styles.

BACKGROUND: The prevalence of depression among college students is higher than that of the general population. Although a growing body of research suggests that depression in college students and their potential risk factors, few studies have focused on the correlation between depression and risk factors. This study aims to explore the mediating role of perceived social support and resilience in the relationship between trait coping styles and depression among college students. METHODS: A total of 1262 college students completed questionnaires including the Trait Coping Styles Questionnaire (TCSQ), the Patient Health Questionnaire-9 (PHQ-9), the Perceived Social Support Scale (PSSS), and the Resilience Scale-14 (RS-14). Common method bias tests and spearman were conducted, then regressions and bootstrap tests were used to examine the mediating effects. RESULTS: In college students, there was a negative correlation between perceived control PC and depression, with a significant direct predictive effect on depression (ß = -0.067, P < 0.01); in contrast, negative control NC showed the opposite relationship (ß = 0.057, P < 0.01). PC significantly positively predicted perceived social support (ß = 0.575, P < 0.01) and psychological resilience (ß = 1.363, P < 0.01); conversely, NC exerted a significant negative impact. Perceived social support could positively predict psychological resilience (ß = 0.303, P < 0.01), and both factors had a significant negative predictive effect on depression. Additionally, Perceived social support and resilience played a significant mediating role in the relationship between trait coping styles and depression among college students, with three mediating paths: PC/NC → perceived social support → depression among college students (-0.049/0.033), PC/NC→ resilience → depression among college students (-0.122/-0.021), and PC/NC → perceived social support → resilience → depression among college students (-0.016/0.026). CONCLUSION: The results indicate that trait coping styles among college students not only directly predict lower depression but also indirectly influence them through perceived social support and resilience. This suggests that guiding students to confront and solve problems can alleviate their depression.

Roles of STAT3 and ZEB1 proteins in E-cadherin down-regulation and human colorectal cancer epithelial-mesenchymal transition.

The progression of colorectal carcinoma (CRC) to invasive and metastatic disease may involve localized occurrences of epithelial-mesenchymal transition (EMT). However, mechanisms of the EMT process in CRC progression are not fully understood. We previously showed that knockdown of signal transducer and activator of transcription 3 (STAT3) up-regulated E-cadherin (a key component in EMT progression) in CRC. In this study, we examined the roles of STAT3 in CRC EMT and ZEB1, an EMT inducer, in STAT3-induced down-regulation of E-cadherin. Knockdown of STAT3 significantly increased E-cadherin and decreased N-cadherin and vimentin expressions in highly invasive LoVo CRC cells. Meanwhile, overexpression of STAT3 significantly reduced E-cadherin and enhanced N-cadherin and vimentin expressions in weakly invasive SW1116 CRC cells. Activation of STAT3 significantly increased CRC cell invasiveness and resistance to apoptosis. Knockdown of STAT3 dramatically enhanced chemosensitivity of CRC cells to fluorouracil. STAT3 regulated ZEB1 expression in CRC cells, and the STAT3-induced decrease in E-cadherin and cell invasion depended on activation of ZEB1 in CRC cells. Additionally, pSTAT3(Tyr-705) and ZEB1 expressions were significantly correlated with TNM (tumor, lymph node, and metastasis stages) (p < 0.01). In conclusion, STAT3 may directly mediate EMT progression and regulate ZEB1 expression in CRC. ZEB1 may participate in STAT3-induced cell invasion and E-cadherin down-regulation in CRC cells. The expressions of pSTAT3(Tyr-705) and ZEB1 may be positively associated with CRC metastasis. Our data may provide potential targets to prevent and/or treat CRC invasion and metastasis.

Developing magnetic barcode bead fluorescence assay for high throughput analyzing humoral responses against multiple SARS-CoV-2 variants.

The continuous mutation of SARS-CoV-2 highlights the need for rapid, cost-effective, and high-throughput detection methods. To better analyze the antibody levels against SARS-CoV-2 and its variants in vaccinated or infected subjects, we developed a multiplex detection named Barcode Bead Fluorescence (BBF) assay. These barcode beads were magnetic, characterized by 2-dimensional edges, highly multiplexed, and could be decrypted with visible light. We conjugated 12 magnetic barcode beads with corresponding nine spike proteins (wild-type, alpha, beta, gamma, delta, and current omicrons), two nucleocapsid proteins (wild-type and omicron), and one negative control. First, the conjugated beads underwent serial quality controls via fluorescence labeling, e.g., reproducibility (R square = 0.99) and detection limits (119 pg via anti-spike antibody). Next, we investigated serums from vaccinated subjects and COVID-19 patients for clinical applications. A significant reduction of antibody levels against all variant beads was observed in both vaccinated and COVID-19 studies. Subjects with two doses of mRNA-1273 exhibited the highest level of antibodies against all spike variants compared to two doses of AZD1222 and unvaccinated. We also found that COVID-19 patients showed higher antibody levels against spike beads from wild-type, alpha, beta, and delta. Finally, the nucleocapsid beads served as markers to distinguish infections from vaccinated subjects. Overall, this study developed the BBF assay for analyzing humoral immune responses, which has the advantages of robustness, automation, scalability, and cost-effectiveness.

Rituximab, but not other biologics, impairs humoral immunity in patients with rheumatoid arthritis-a study using CoVariant protein arrays.

Objectives: RA is an autoimmune disease characterized by chronic inflammation and joint destruction. Biologics are crucial to achieving treat-to-target goals in patients with RA. The global spread and continuous variation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) necessitate the monitoring of variant-specific humoral responses post-vaccination. The aim of this study was to investigate how different biologic treatments for vaccinated RA patients might affect their neutralizing antibodies against multiple SARS-CoV-2 variants. Methods: We recruited RA patients who had received three doses of conventional SARS-CoV-2 vaccines and were treated with various biologics, e.g. TNF inhibitor (etanercept), IL-6 inhibitor (tocilizumab), CTLA4-Ig (abatacept) or anti-CD20 (rituximab). Serum samples were used to profile the binding and neutralizing antibodies using our own SARS-CoV-2 variant (CoVariant) protein array, developed previously. Results: Compared with healthy controls, only RA therapy with rituximab showed a reduction in neutralizing antibodies capable of targeting spike proteins in SARS-CoV-2 wild-type and most variants. This reduction was not observed in binding antibodies against SARS-CoV-2 wild-type or its variants. Conclusion: After receiving three doses of SARS-CoV-2 vaccination, RA patients who underwent rituximab treatment generated sufficient antibodies but exhibited lower neutralizing activities against wild-type and multiple variants, including current Omicron. Other biological DMARDs, e.g. TNF inhibitor, IL-6 inhibitor and CTLA4-Ig, did not show obvious inhibition.

Metformin Reprograms Tryptophan Metabolism to Stimulate CD8+ T-cell Function in Colorectal Cancer.

Colorectal carcinogenesis coincides with immune cell dysfunction. Metformin has been reported to play a role in stimulating antitumor immunity, suggesting it could be used to overcome immunosuppression in colorectal cancer. Herein, using single-cell RNA sequencing (scRNA-seq), we showed that metformin remodels the immune landscape of colorectal cancer. In particular, metformin treatment expanded the proportion of CD8+ T cells and potentiated their function. Analysis of the metabolic activities of cells in the colorectal cancer tumor microenvironment (TME) at a single-cell resolution demonstrated that metformin reprogrammed tryptophan metabolism, which was reduced in colorectal cancer cells and increased in CD8+ T cells. Untreated colorectal cancer cells outcompeted CD8+ T cells for tryptophan, leading to impaired CD8+ T-cell function. Metformin in turn reduced tryptophan uptake by colorectal cancer cells, thereby restoring tryptophan availability for CD8+ T cells and increasing their cytotoxicity. Metformin inhibited tryptophan uptake in colorectal cancer cells by downregulating MYC, which led to a reduction in the tryptophan transporter SLC7A5. This work highlights metformin as an essential regulator of T-cell antitumor immunity by reprogramming tryptophan metabolism, suggesting it could be a potential immunotherapeutic strategy for treating colorectal cancer. SIGNIFICANCE: Analysis of the impact of metformin on the colorectal cancer immunometabolic landscape at a single-cell resolution shows that metformin alters cancer cell tryptophan metabolism to stimulate CD8+ T-cell antitumor activity.

Microbiota-derived tryptophan catabolites mediate the chemopreventive effects of statins on colorectal cancer.

Epidemiological studies have indicated an association between statin use and reduced incidence of colorectal cancer (CRC), and work in preclinical models has demonstrated a potential chemopreventive effect. Statins are also associated with reduced dysbiosis in the gut microbiome, yet the role of the gut microbiome in the protective effect of statins in CRC is unclear. Here we validated the chemopreventive role of statins by retrospectively analysing a cohort of patients who underwent colonoscopies. This was confirmed in preclinical models and patient cohorts, and we found that reduced tumour burden was partly due to statin modulation of the gut microbiota. Specifically, the gut commensal Lactobacillus reuteri was increased as a result of increased microbial tryptophan availability in the gut after atorvastatin treatment. Our in vivo studies further revealed that L. reuteri administration suppressed colorectal tumorigenesis via the tryptophan catabolite, indole-3-lactic acid (ILA). ILA exerted anti-tumorigenic effects by downregulating the IL-17 signalling pathway. This microbial metabolite inhibited T helper 17 cell differentiation by targeting the nuclear receptor, RAR-related orphan receptor γt (RORγt). Together, our study provides insights into an anti-cancer mechanism driven by statin use and suggests that interventions with L. reuteri or ILA could complement chemoprevention strategies for CRC.