draining-lymph-node-metastasis-model-for-assessing-dynamics-antigen

Draining Lymph Node Metastasis Model for Assessing the Dynamics of Antigen-Specific CD8<sup>+</sup> T Cells During Tumorigenesis

Tumor antigen-specific CD8+ T cells from draining lymph nodes gain an accumulating importance in mounting anti-tumor immune response during tumorigenesis. ...

Third Military Medical University

Our previous study showed that dengue virus 2 (DENV2) infection induces rearrangement of vimentin into dense structures at the perinuclear area. However, the underlying mechanism of this phenomenon is poorly characterized. In the present work, we found that vimentin and Ser71 phosphorylated vimentin display similar distributions in DENV2-infected cells. DENV2 infection also induced ROCK activation and phosphorylation of vimentin at Ser71 as the DENV2 infection progressed. Furthermore, Ser71 phosphorylation and vimentin rearrangement induced by DENV2 infection were blocked by the ROCK inhibitor Y-27632. In addition, DENV2 led to endoplasmic reticulum (ER) redistribution in the perinuclear region of the host cells, which was partially blocked by pretreatment with Y-27632. Together, these data support indicate that ROCK may have a role in governing regulating vimentin and ER rearrangement during DENV2 infection. We hypothesize that DENV2 infection, via ROCK activation, induces both vimentin rearrangement and ER redistribution around the perinuclear region, which may play a structural role in anchoring DENV2 to replication sites.

ROCK is involved in vimentin phosphorylation and rearrangement induced by dengue virus.

TW-37 is a novel, potent and non-peptide Bcl-2 small-molecule inhibitor. Its activity in colorectal cancer (CRC) cells is studied. In both HCT-116 cells and primary human colon cancer cells, treatment with TW-37 at only nM concentration efficiently inhibited cell survival and proliferation. TW-37 also induced caspase-3/9 and apoptosis activation in CRC cells. Feedback autophagy activation was observed in TW-37-treated CRC cells. Reversely pharmacological autophagy inhibition or Beclin-1 knockdown by targeted-shRNA potentiated TW-37-induced apoptosis and killing of CRC cells. In vivo, intravenous injection of TW-37 inhibited HCT-116 tumor growth in mice. TW-37's anti-tumor activity was further potentiated against Beclin-1-silenced HCT-116 tumors. Together, targeting Bcl-2 family protein by TW-37 efficiently inhibits CRC cell growth in vitro and in vivo. Inhibition of feedback autophagy activation could further sensitize TW-37.

The preclinical analysis of TW-37 as a potential anti-colorectal cancer cell agent.

Alcohol consumption causes liver steatosis in humans. Metabolic disorders of lipids are one of the factors that cause liver steatosis in hepatocytes. Hepatic Niemann‑Pick C1‑like 1 (NPC1L1) regulates lipid homeostasis in mammals. The relationship between NPC1L1 and autophagy in those with a history of alcohol abuse is unclear. The present study aimed to investigate the function of NPC1L1 in the activation of hepatic autophagy in a mouse model with a human (h)NPC1L1 transgene under alcohol feeding conditions. The mice expressing hNPC1L1 (Ad‑L1) or controls (Ad‑null) were created by retro‑orbital adenovirus injection. The Ad‑L1 and Ad‑null mice were fed with alcohol or a non‑alcoholic diet to mimic chronic alcohol consumption in humans. Hepatic autophagy was demonstrated in isolated primary hepatocytes by monitoring autophagic vacuoles under fluorescence microscopy, and by western blotting for autophagic makers. Isolated hepatocytes from the livers of Ad‑L1 mice were treated with different doses of ezetimibe to study the restoration of autophagy. Chronic alcohol feeding caused liver injury and steatosis, shown by significantly higher levels of plasma alanine transaminase and aspartate transaminase activity, and by hematoxylin and eosin staining in Ad‑L1 and Ad‑null mice. Compared to Ad‑null control mice, the microtubule‑associated proteins 1A/1B light chain 3 (LC3) particles in the isolated hepatocytes of Ad‑L1 mice were decreased, both under alcohol and non‑alcoholic feeding. The ratio of LC3II/LC3I was significantly decreased, and the level of p62/sequestosome‑1 protein was significantly increased in Ad‑L1 mice compared with Ad‑null mice after alcohol feeding. Levels of LC3II protein were statistically increased in hepatocytes isolated from Ad‑L1 mice with ezetimibe treatment. The increase in LC3II expression was dose dependent. Within the tested range, it reached its highest level at 40 µM. The livers of Ad‑L1 mice represent a more human‑like state for the study of hepatic autophagy. Hepatic expression of human NPC1L1 resulted in an inhibition of autophagy; it may contribute to alcoholic fatty liver disease in humans.

Hepatic NPC1L1 overexpression attenuates alcoholic autophagy in mice.

Antigen-specific memory CD4 T cells can persist and confer rapid and efficient protection from microbial reinfection. However, the mechanisms underlying the long-term maintenance of the memory CD4 T cell pool remain largely unknown. Here, using a mouse model of acute infection with lymphocytic choriomeningitis virus (LCMV), we found that the serine/threonine kinase complex mammalian target of rapamycin complex 2 (mTORC2) is critical for the long-term persistence of virus-specific memory CD4 T cells. The perturbation of mTORC2 signaling at memory phase led to an enormous loss of virus-specific memory CD4 T cells by a unique form of regulated cell death (RCD), ferroptosis. Mechanistically, mTORC2 inactivation resulted in the impaired phosphorylation of downstream AKT and GSK3β kinases, which induced aberrant mitochondrial reactive oxygen species (ROS) accumulation and ensuing ferroptosis-causative lipid peroxidation in virus-specific memory CD4 T cells; furthermore, the disruption of this signaling cascade also inhibited glutathione peroxidase 4 (GPX4), a major scavenger of lipid peroxidation. Thus, the mTORC2-AKT-GSK3β axis functions as a key signaling hub to promote the longevity of virus-specific memory CD4 T cells by preventing ferroptosis.

The kinase complex mTORC2 promotes the longevity of virus-specific memory CD4 T cells by preventing ferroptosis.

Antitumor therapeutic vaccines are generally based on antigenic epitopes presented by major histocompatibility complex (MHC-I) molecules to induce tumor-specific CD8 T cells. Paradoxically, continuous T cell receptor (TCR) stimulation from tumor-derived CD8 T-cell epitopes can drive the functional exhaustion of tumor-specific CD8 T cells. Tumor-specific type-I helper CD4 T (T1) cells play an important role in the population maintenance and cytotoxic function of exhausted tumor-specific CD8 T cells in the tumor microenvironment. Nonetheless, whether the vaccination strategy targeting MHC-II-restricted CD4 T-cell epitopes to induce tumor-specific T1 responses can confer effective antitumor immunity to restrain tumor growth is not well studied. Here, we developed a heterologous prime-boost vaccination strategy to effectively induce tumor-specific T1 cells and evaluated its antitumor efficacy and its capacity to potentiate PD-1/PD-L1 immunotherapy.

CD4 T-cell epitope-based heterologous prime-boost vaccination potentiates anti-tumor immunity and PD-1/PD-L1 immunotherapy.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs), especially the Delta and Omicron variants, have been reported to show significant resistance to approved neutralizing monoclonal antibodies (mAbs) and vaccines. We previously identified a mAb named 35B5 that harbors broad neutralization to SARS-CoV-2 VOCs. Herein, we explored the protection efficacy of a 35B5-based nasal spray against SARS-CoV-2 VOCs in a small-scale clinical trial.

Nasal Spray of Neutralizing Monoclonal Antibody 35B5 Confers Potential Prophylaxis Against Severe Acute Respiratory Syndrome Coronavirus 2 Variants of Concern: A Small-Scale Clinical Trial.

Follicular helper T (T) cells provide specialized help for B cells to ensure optimal humoral immunity. The histone methyltransferase EZH2, as a chromatin repressor, secures the T differentiation by promoting T lineage associated gene expression during acute viral infection, including  and . By using conditional deletion murine system, we observed that EZH2 ablation in CD4 T cells was accompanied by aberrant accumulation of DNA methyltransferases (DNMTs) DNMT1 and DNMT3B in T cells. And the loss of EZH2 promoted aggravation of DNA methylation status at  locus. Therefore, our findings suggested that EZH2 plays an important role in maintenance of hypomethylation at  locus thus affecting T differentiation during acute viral infection.

EZH2 restricts  DNA methylation and promotes T differentiation during acute viral infection.

Blocking PD-1/PD-L1 signaling transforms cancer therapy and is assumed to unleash exhausted tumor-reactive CD8 T cells in the tumor microenvironment (TME). However, recent studies have also indicated that the systemic tumor-reactive CD8 T cells may respond to PD-1/PD-L1 immunotherapy. These discrepancies highlight the importance of further defining tumor-specific CD8 T cell responders to PD-1/PD-L1 blockade. Here, using multiple preclinical tumor models, we revealed that a subset of tumor-specific CD8 cells in the tumor draining lymph nodes (TdLNs) was not functionally exhausted but exhibited canonical memory characteristics. TdLN-derived tumor-specific memory (T) cells established memory-associated epigenetic program early during tumorigenesis. More importantly, TdLN-T cells exhibited superior anti-tumor therapeutic efficacy after adoptive transfer and were characterized as bona fide responders to PD-1/PD-L1 blockade. These findings highlight that TdLN-T cells could be harnessed to potentiate anti-tumor immunotherapy.

Shun Lei

Institute of Immunology

Third Military Medical University

Draining Lymph Node Metastasis Model for Assessing the Dynamics of Antigen-Specific CD8⁺ T Cells During Tumorigenesis

Shun Lei

Institute of Immunology

Third Military Medical University

Draining Lymph Node Metastasis Model for Assessing the Dynamics of Antigen-Specific CD8+ T Cells During Tumorigenesis

Draining Lymph Node Metastasis Model for Assessing the Dynamics of Antigen-Specific CD8⁺ T Cells During Tumorigenesis