An IκB Kinase-Regulated Feedforward Circuit Prolongs Inflammation

Natural lung-tropic TH9 cells: a sharp weapon for established lung metastases

BACKGROUND

Lung metastasis remains the primary cause of tumor-related mortality, with limited treatment options and unsatisfactory efficacy. In preclinical studies, T helper 9 (TH9) cells have shown promise in treating solid tumors. However, it is unclear whether TH9 cells can tackle more challenging situations, such as established lung metastases. Moreover, comprehensive exploration into the nuanced biological attributes of TH9 cells is imperative to further unravel their therapeutic potential.

METHODS

We adoptively transferred TH1, TH9, and TH17 cells into subcutaneous, in situ, and established lung metastases models of osteosarcoma and triple-negative breast cancer, respectively, comparing their therapeutic efficacy within each distinct model. We employed flow cytometry and an in vivo imaging system to evaluate the accumulation patterns of TH1, TH9, and TH17 cells in the lungs after transfusion. We conducted bulk RNA sequencing on in vitro differentiated TH9 cells to elucidate the chemokine receptor CXCR4, which governs their heightened pulmonary tropism relative to TH1 and TH17 cell counterparts. Using Cd4 cre Cxcr4 flox/flox mice, we investigate the effects of CXCR4 on the lung tropism of TH9 cells. We performed mass spectrometry to identify the E3 ligase responsible for CXCR4 ubiquitination and elucidated the mechanism governing CXCR4 expression within TH9 cellular milieu. Ultimately, we analyzed the tumor immune composition after TH9 cell transfusion and evaluated the therapeutic efficacy of adjunctive anti-programmed cell death protein-1 (PD-1) therapy in conjunction with TH9 cells.

RESULTS

In this study, we provide evidence that TH9 cells exhibit higher lung tropism than TH1 and TH17 cells, thereby exhibiting exceptional efficacy in combating established lung metastases. CXCR4-CXCL12 axis is responsible for lung tropism of TH9 cells as ablating CXCR4 in CD4+ T cells reverses their lung accumulation. Mechanistically, tumor necrosis factor receptor-associated factor 6 (TRAF6)-driven hyperactivation of NF-κB signaling in TH9 cells inhibited ITCH-mediated ubiquitination of CXCR4, resulting in increased CXCR4 accumulation and enhanced lung tropism of TH9 cells. Besides, TH9 cells' transfusion significantly improved the immunosuppressed microenvironment. TH9 cells and anti-PD-1 exhibit synergistic effects in tumor control.

CONCLUSIONS

Our findings emphasized the innate lung tropism of TH9 cells driven by the activation of TRAF6, which supports the potential of TH9 cells as a promising therapy for established lung metastases.

Acetylation, Phosphorylation, Ubiquitination (Oh My!): Following Post-Translational Modifications on the Ubiquitin Road

Ubiquitination is controlled by a series of E1, E2, and E3 enzymes that can ligate ubiquitin to cellular proteins and dictate the turnover of a substrate and the outcome of signalling events such as DNA damage repair and cell cycle. This process is complex due to the combinatorial power of ~35 E2 and ~1000 E3 enzymes involved and the multiple lysine residues on ubiquitin that can be used to assemble polyubiquitin chains. Recently, mass spectrometric methods have identified that most enzymes in the ubiquitination cascade can be further modified through acetylation or phosphorylation under particular cellular conditions and altered modifications have been noted in different cancers and neurodegenerative diseases. This review provides a cohesive summary of ubiquitination, acetylation, and phosphorylation sites in ubiquitin, the human E1 enzyme UBA1, all E2 enzymes, and some representative E3 enzymes. The potential impacts these post-translational modifications might have on each protein function are highlighted, as well as the observations from human disease.

Localization of the ubiquitin ligase Dma1 to the fission yeast contractile ring is modulated by phosphorylation

The timing of cytokinesis relative to other mitotic events in the fission yeast Schizosaccharomyces pombe is controlled by the septation initiation network (SIN). During a mitotic checkpoint, the SIN is inhibited by the E3 ubiquitin ligase Dma1 to prevent chromosome mis-segregation. Dma1 dynamically localizes to spindle pole bodies (SPBs) and the contractile ring (CR) during mitosis, though its role at the CR is unknown. Here, we examined whether Dma1 phosphorylation affects its localization or function. We found that preventing Dma1 phosphorylation by substituting the six phosphosites with alanines diminished its CR localization but did not affect its mitotic checkpoint function. These studies reinforce the conclusion that Dma1 localization to the SPB is key to its role in the mitotic checkpoint.

CORM-2 inhibits intracerebral hemorrhage-mediated inflammation

Background and purpose: Low-dose of carbon monoxide delivered by CO-releasing molecule-2 (CORM-2) had been confirmed having anti-inflammatory efficacy in some inflammatory diseases. Herein, we assessed the usefulness of CORM-2 in correcting intracerebral hemorrhage (ICH)-mediated inflammation.Methods: Healthy male Sprague Dawley (SD) rats randomly entered into four groups: sham-ICH, ICH, ICH+CORM-2, and ICH+ inactive carbon monoxide releasing molecule 2 (iCORM-2). ICH was induced by 50 μl of autologous arterial blood injected in situ in the rat brain. Neuro-functions of the ICH rats were evaluated with Garcia 18 scores at the 6th, 24th , 48th hou, and the fifthh day post-ICH. And brain tissues surrounding the hematoma area were collected from all ICH rats and assayed with Western blot and immunofluoresence analysis.Results: Neuro-dysfunctions in ICH rats were very severe than those in ICH +CORM-2 rats. Compared to sham group, the levels of HO-1, IKKβ, NF-κB, and TNF-α in ICH group began to elevate at the 6th hour, and reached to peak at the 48th hour post-ICH, all p < 0.05. While in ICH +CORM-2 group, the expressions of IKKβ, NF-κB, and TNF-α were very weaker than that in ICH group at every time points mentioned above; however, this phenomenon was not reproduced in ICH + iCORM-2 group. HO-1 in ICH+CORM-2 group highlighted in perihematomal area with many activated microglia (Iba-1-positive cells) and co-expressed with TNF-α, all of which were diminished at the fifth day post-ICH.Conclusion: CORM-2 may attenuate ICH-mediated inflammation by inhibiting microglial activation, which may involve the IKK/NF-κB pathway.AbbreviationsICH: intracerebral hemorrhage; CO: carbon monoxide; CORM-2: carbon monoxide releasing molecule-2; iCORM-2: inactive carbon monoxide releasing molecule-2; HO-1: heme oxygenase 1; IKKβ: inhibitor of IκB kinases β; NF-κB: nuclear factor-κB; TNF-α: tumor necrosis factor-α; Iba-1: ionized calcium binding adaptor molecule-1; IκB: inhibitor of NF-κB; iNOS: inducible nitric oxide synthase; Keap1: Kelch-like ECH-associated protein 1; Nrf2: NF-E2-related factor 2; DMSO: dimethylsulfoxide.

The Role of Non-coding RNAs in Viral Myocarditis

Viral myocarditis (VMC) is a disease characterized as myocardial parenchyma or interstitium inflammation caused by virus infection, especially Coxsackievirus B3 (CVB3) infection, which has no accurate non-invasive examination for diagnosis and specific drugs for treatment. The mechanism of CVB3-induced VMC may be related to direct myocardial damage of virus infection and extensive damage of abnormal immune response after infection. Non-coding RNA (ncRNA) refers to RNA that is not translated into protein and plays a vital role in many biological processes. There is expanding evidence to reveal that ncRNAs regulate the occurrence and development of VMC, which may provide new treatment or diagnosis targets. In this review, we mainly demonstrate an overview of the potential role of ncRNAs in the pathogenesis, diagnosis and treatment of CVB3-induced VMC.

ITCH as a potential therapeutic target in human cancers

The ITCH/AIP4 ubiquitin E3 ligase was discovered independently by two groups searching for atrophin-1 interacting proteins and studying the genetics of mouse coat color alteration, respectively. ITCH is classified as a NEDD4 family E3 ligase featured with the C-terminal HECT domain for E3 ligase function and WW domains for substrate recruiting. ITCH deficiency in the mouse causes severe multi-organ autoimmune disease. Its roles in maintaining a balanced immune response have been extensively characterized over the past two and a half decades. A wealth of reports demonstrate a multifaceted role of ITCH in human cancers. Given the versatility of ITCH in catalyzing both proteolytic and non-proteolytic ubiquitination of its over fifty substrates, ITCH's role in malignancies is believed to be context-dependent. In this review, we summarize the downstream substrates of ITCH, the functions of ITCH in both tumor cells and the immune system, as well as the implications of such functions in human cancers. Moreover, we describe the upstream regulatory mechanisms of ITCH and the efforts have been made to target ITCH using small molecule inhibitors.

Extracellular vesicle–mediated transfer of constitutively active MyD88L265P engages MyD88wt and activates signaling

MyD88L265P is present in the EVs secreted by WM cancer cells and triggers signaling in the recipient cells. MyD88-containing EVs shape the proinflammatory microenvironment in the bone marrow.

Phosphorylation of the E3 ubiquitin protein ligase ITCH diminishes binding to its cognate E2 ubiquitin ligase

Heightened and extended inflammation underlies the pathogenesis of many disorders, including inflammatory bowel disease, sepsis, and inflammatory arthritis. Ubiquitin networks help dictate the strength and duration of inflammatory signaling. In innate immunity, the itchy E3 ubiquitin protein ligase (ITCH)-A20 ubiquitin-editing complex inhibits receptor-interacting Ser/Thr kinase (RIPK) activation by removing Lys-63-linked polyubiquitinated chains from key proteins in the nuclear factor kappa B (NF-κB) signaling pathway. The complex then attaches polyubiquitinated chains to these proteins to target them for lysosomal or proteasomal destruction. ITCH is phosphorylated and thereby inhibited by inhibitor of nuclear factor kappa B kinase subunit beta (IKKβ) to fine-tune the inflammatory response to the strength of the offending signal. However, the biochemical mechanism by which E3 ubiquitination is impaired by IKK-driven phosphorylation remains unclear. Here, we report that this phosphorylation impedes ITCH binding to its cognate E2 ubiquitin ligase, UbcH7. Using CRISPR-Cas9 genetic knockout to mimic the ITCH-UbcH7-inhibited state, we further show that genetic UbcH7 deficiency phenocopies ITCH phosphorylation in regulating RIPK2 ubiquitination. We conclude that phosphorylation can disrupt the binding of an E3 ubiquitin ligase to an E2-conjugating enzyme, leading to prolonged inflammatory signaling. To our knowledge, this is the first report of E3 ubiquitin ligase phosphorylation inhibiting E3 ligase activity by impairing E2-E3 complex formation.

Runt-Related Transcription Factor 1 Regulates LPS-Induced Acute Lung Injury via NF-κB Signaling

Runt-related transcription factor 1 (RUNX1), a transcription factor expressed in multiple organs, plays important roles in embryonic development and hematopoiesis. Although RUNX1 is highly expressed in pulmonary tissues, its roles in lung function and homeostasis are unknown. We sought to assess the role of RUNX1 in lung development and inflammation after LPS challenge. Expression of RUNX1 was assessed in the developing and postnatal lung. RUNX1 was conditionally deleted in pulmonary epithelial cells. Pulmonary maturation was evaluated in the developing and postnatal lung, and lung inflammation was investigated in adult mice after LPS challenge. Interactions between RUNX1 and inflammatory signaling via NF-κB-IkB kinase β were assessed in vitro. RUNX1 was expressed in both mesenchymal and epithelial compartments of the developing and postnatal lung. The RUNX1 gene was efficiently deleted from respiratory epithelial cells producing Runx1^∆/∆ mice. Although lung maturation was delayed, Runx1^∆/∆ mice survived postnatally and subsequent growth and maturation of the lung proceeded normally. Increased respiratory distress, inflammation, and proinflammatory cytokines were observed in the Runx1-deleted mice after pulmonary LPS exposure. RUNX1 deletion was associated with the activation of NF-κB in respiratory epithelial cells. RUNX1 was required for the suppression of NF-κB signaling pathway via inhibition of IkB kinase β in in vitro studies. RUNX1 plays a critical role in the lung inflammation after LPS-induced injury.

Vinpocetine Inhibits NF-κB-Dependent Inflammation in Acute Ischemic Stroke Patients

Immunity and inflammation play critical roles in the pathogenesis of acute ischemic stroke. Therefore, immune intervention, as a new therapeutic strategy, is worthy of exploration. Here, we tested the inflammation modulator, vinpocetine, for its effect on the outcomes of stroke. For this multi-center study, we recruited 60 patients with anterior cerebral circulation occlusion and onset of stroke that had exceeded 4.5 h but lasted less than 48 h. These patients, after random division into two groups, received either standard management alone (controls) or standard management plus vinpocetine (30 mg per day intravenously for 14 consecutive days, Gedeon Richter Plc., Hungary). Vinpocetine treatment did not change the lymphocyte count; however, nuclear factor kappa-light-chain-enhancer of activated B cell activation was inhibited as seen not only by the increased transcription of IκBα mRNA but also by the impeded phosphorylation and degradation of IκBα and subsequent induction of pro-inflammatory mediators. These effects led to significantly reduced secondary lesion enlargement and an attenuated inflammation reaction. Compared to controls, patients treated with vinpocetine had a better recovery of neurological function and improved clinical outcomes during the acute phase and at 3-month follow-up. These findings identify vinpocetine as an inflammation modulator that could improve clinical outcomes after acute ischemic stroke. This study also indicated the important role of immunity and inflammation in the pathogenesis of acute ischemic stroke and the significance of immunomodulatory treatment.

CLINICAL TRIAL REGISTRATION INFORMATION

www.clinicaltrials.gov . Identifier: NCT02878772.