Accumulation Of Cells Research Articles

Protective effect of TCR-mediated MAIT cell activation during experimental autoimmune encephalomyelitis

Mucosal-associated invariant T (MAIT) cells express semi-invariant T cell receptors (TCR) for recognizing bacterial and yeast antigens derived from riboflavin metabolites presented on the non-polymorphic MHC class I-related protein 1 (MR1). Neuroinflammation in multiple sclerosis (MS) is likely initiated by autoreactive T cells and perpetuated by infiltration of additional immune cells, but the precise role of MAIT cells in MS pathogenesis remains unknown. Here, we use experimental autoimmune encephalomyelitis (EAE), a mouse model of MS, and find an accumulation of MAIT cells in the inflamed central nervous system (CNS) enriched for MAIT17 (RORγt+) and MAIT1/17 (T-bet+RORγt+) subsets with inflammatory and protective features. Results from transcriptome profiling and Nur77GFP reporter mice show that these CNS MAIT cells are activated via cytokines and TCR. Blocking TCR activation with an anti-MR1 antibody exacerbates EAE, whereas enhancing TCR activation with the cognate antigen, 5-(2-oxopropylideneamino)−6-D-ribitylaminouracil, ameliorates EAE severity, potentially via the induction of amphiregulin (AREG). In summary, our findings suggest that TCR-mediated MAIT cell activation is protective in CNS inflammation, likely involving an induction of AREG.

Potential effects of a human milk oligosaccharide 6'-sialyllactose on angiotensin II-induced aortic aneurysm via p90RSK/TGF-β/SMAD2 signaling pathway.

The aberrant phenotypic transformation of vascular smooth muscle cells (VSMCs) is a key factor in the formation of aortic aneurysm (AA). This study aimed to explore theeffects of 6'-sialyllactose (6'-SL), a human milk oligosaccharide, on angiotensin II (Ang II)-induced VSMC dysfunction and AA formation both in vitro and in vivo. An AA model was established in male C57BL/6 mice challenged with Ang II via osmotic pumps and a lysyl oxidase inhibitor, β-aminopropionitrile (BAPN), in drinking water. The mice were administered with 6'-SL, FMK (a p90RSK inhibitor), or losartan (as a positive control). In vitro, VSMCs were pretreated with 6'-SL before Ang II stimulation. We found that p90RSK inhibition abolished Ang II/BAPN-induced thoracic AA and abdominal AA formation. Treatment with 100mg/kg 6'-SL significantly attenuated Ang II/BAPN-induced aortic dilatation. 6'-SL attenuated Ang II-induced collagen deposition, calcification, and immune cell accumulation. Consistently, 6'-SL downregulated p-p90RSK, p90RSK, and p-SMAD2, and mitigated VSMC contractility loss, as indicated by α-SMA expression in vivo. Interestingly, Ang II-induced transforming growth factor-beta (TGF-β) signaling pathway was suppressed by p90RSK inhibition in VSMCs. 6'-SL treatment significantly reduced TGF-β/SMAD2 targets, including dedifferentiation markers such asosteopontin and vimentin, and elastin degradation factors MMP2 and MMP9. Overexpression of p90RSK in VSMCs enhanced TGF-β and abrogated the effects of 6'-SL. Furthermore, 6'-SL co-treatment abolished high phosphate-induced calcification in vitro via p90RSK/TGF-β signaling pathway. Altogether, our findings suggest that 6'-SL could be a potential therapeutic candidate for protecting against Ang II-induced AA formation by inhibiting the p90RSK/TGF-β/SMAD2 signaling pathway.

A cross‐sectional study on quality of life in adult indolent systemic mastocytosis and its association with cutaneous involvement

AbstractBackgroundSystemic mastocytosis (SM) is characterized by abnormal mast cell accumulation in various tissues, including the skin, and encompasses several clinical variants, ranging from less aggressive to more severe forms. ISM, the most common variant, often presents with cutaneous manifestations, causing significant impairment in QoL due to mediator‐release symptoms and stigma associated with typical cutaneous lesions.ObjectivesThe study aimed to assess QoL impairment in ISM patients and its correlation with demographic and clinical data.MethodsA cohort of 52 adult ISM patients was evaluated using the Dermatology Life Quality Index (DLQI) and the mastocytosis QoL questionnaire (MC‐QoL). Questionnaire scores were then analyzed in relation to the clinical and demographic characteristics of the patients.ResultsOver half of the patients experienced mild or higher levels of impairment in QoL, with female patients showing greater impairment than males. Patients with recent symptom onset reported higher MC‐QoL scores, possibly due to psychological factors and lack of disease knowledge. Cutaneous symptoms significantly impacted QoL, and the visibility of lesions affected DLQI scores more than MC‐QoL scores. A moderately strong correlation was observed between DLQI and MC‐QoL scores, particularly in the Skin and Social Life domains. The study highlights gender differences in QoL impairment, suggesting the need for further investigation into potential social or cultural factors.ConclusionsWhile the study provides valuable insights into QoL impairment in ISM patients, its monocentric nature and small sample size are notable limitations. Further research is warranted to better understand the impact of SM on patients' well‐being and to identify effective strategies for managing symptoms and improving overall QoL in this population.

An update on ox-LDL-inducing vascular smooth muscle cell-derived foam cells in atherosclerosis.

Excess cholesterol accumulation induces the accumulation of foam cells, eventually accelerating atherosclerosis progress. Historically, the mechanisms of macrophage-derived foam cells have attracted attention because of their central role in plaque development, which was challenged by lineage tracing in union with single-cell sequencing (sc-seq). Accumulated studies have uncovered how vascular smooth muscle cells (VSMCs) proliferate and migrate to the vascular intima and accumulate, then transform into foam cells induced by surplus lipids, finally accounting for 30% to 70% of the total foam cells within the plaque of both mice and humans. Therefore, the mechanisms of VSMC-derived foam cells have received increasing attention. The review intends to summarize the transformation mechanism of VSMCs into foam cells induced by oxidized low-density lipoproteins (ox-LDL) in atherosclerosis.

TFAM as a sensor of UVC-induced mitochondrial DNA damage.

Mitochondria lack nucleotide excision DNA repair; however, mitochondrial DNA (mtDNA) is resistant to mutation accumulation following DNA damage. These observations suggest additional damage sensing or protection mechanisms. Transcription Factor A, Mitochondrial (TFAM) compacts mtDNA into nucleoids. As such, TFAM has emerged as a candidate for protecting DNA or sensing damage. To examine these possibilities, we used live-cell imaging, cell-based assays, atomic force microscopy, and high-throughput protein-DNA binding assays to characterize the binding properties of TFAM to UVC-irradiated DNA and cellular consequences of UVC irradiation. Our data indicate an increase in mtDNA degradation and turnover, without a loss in mitochondrial membrane potential that might trigger mitophagy. We identified a reduction in sequence specificity of TFAM associated with UVC irradiation and a redistribution of TFAM binding throughout the mitochondrial genome. Our AFM data show increased compaction of DNA by TFAM in the presence of damage. Despite the TFAM-mediated compaction of mtDNA, we do not observe any protective effect on DNA damage accumulation in cells or in vitro . Taken together, these studies indicate that UVC-induced DNA damage promotes compaction by TFAM, suggesting that TFAM may act as a damage sensor, sequestering damaged genomes to prevent mutagenesis by direct removal or suppression of replication.

Nanoplastics: Immune Impact, Detection, and Internalization after Human Blood Exposure by Single-Cell Mass Cytometry.

The increasing exposure to nanoplastics (NPs) raises significant concerns for human health, primarily due to their potential bioaccumulative properties. While NPs have recently been detected in human blood, their interactions with specific immune cell subtypes and their impact on immune regulation remain unclear. In this proof-of-concept study, model palladium-doped polystyrene NPs (PS-Pd NPs) are utilized to enable single-cell mass cytometry (CyTOF) detection. The size-dependent impact of carboxylate polystyrene NPs (50-200 nm) is investigated across 15 primary immune cell subpopulations using CyTOF. By taking advantage of Pd-doping for detecting PS-Pd NPs, this work evaluates their impact on human immune-cells at the single-cell level following blood exposure. This work traces PS-Pd NPs in 37 primary immune-cell subpopulations from human blood, quantifying the palladium atom count per cell by CyTOF while simultaneously assessing the impact of PS-Pd NPs on cell viability, functionality, and uptake. These results demonstrate that NPs can interact with, interfere with, and translocate into several immune cell subpopulations after exposure. In vivo distribution experiments in mice further confirmed their accumulation in immune cells within the liver, blood, and spleen, particularly in monocytes, macrophages, and dendritic cells. These findings provide valuable insights into the impact of NPs on human health.

Impairment of spinal CSF flow precedes immune cell infiltration in an active EAE model

Accumulation of immune cells and proteins in the subarachnoid space (SAS) is found during multiple sclerosis and in the animal model experimental autoimmune encephalomyelitis (EAE). Whether the flow of cerebrospinal fluid (CSF) along the SAS of the spinal cord is impacted is yet unknown. Combining intravital near-infrared (NIR) imaging with histopathological analyses, we observed a significantly impaired bulk flow of CSF tracers within the SAS of the spinal cord prior to EAE onset, which persisted until peak stage and was only partially recovered during chronic disease. The impairment of spinal CSF flow coincided with the appearance of fibrin aggregates in the SAS, however, it preceded immune cell infiltration and breakdown of the glia limitans superficialis. Conversely, cranial CSF efflux to cervical lymph nodes was not altered during the disease course. Our study highlights an early and persistent impairment of spinal CSF flow and suggests it as a sensitive imaging biomarker for pathological changes within the leptomeninges.

Homeostatic nanomedicine: Protein S-nitrosylation dyshomeostasis dominated oncotherapy based on a tumor-microenvironment-activated nanoparticle

Nitric oxide (NO) holds promise as a therapeutic agent in oncotherapy, yet its efficacy is hindered by low bioavailability, concentration-dependency, and tumor resistance to nitrosative stress. To overcome these limitations, herein, we propose a novel strategy aimed at specifically breaking the protein S-nitrosylation homeostasis of tumors. An acid-responsive nanoplatform comprising amorphous iron / mesoporous silica (AMSP) is constructed to orchestrate synergistic anti-tumor effect of Fe2+ and NO. Activating by the tumor microenvironment, nanopores of AMSP facilitate the in-situ generation of dinitrosyl iron complexes, promoting the physiological stability of NO and protein S-nitrosylation via transnitrosylation. Moreover, the released Fe2+ accelerate reactive oxygen species accumulation in tumor cells, which not only derives stronger nitrating reagents, but also inhibits the denitrosylation reaction triggered by tumor-expressed reducing species. The multiple effects of AMSP induce excessive cellular S-nitrosylation, thereby guiding an untraditional apoptotic pathway, glyceraldehyde-3-phosphate dehydrogenase S-nitrosylation mediated nuclear translocation and protein degradation. Overall, our findings offer a new paradigm of homeostatic nanomedicine, potentially advancing oncotherapy modalities.

Viscoelastic Fluid Focusing Chip-ICP-MS Single-Cell Analysis Enables Elucidating the Effect of Extracellular Polymeric Substances on Bioaccumulation of Hg2+/HgS in Microcystis aeruginosa Cell.

Understanding the interactions between mercury and microalgae, especially the interactions between inorganic mercury (IHg) and extracellular polymeric substances (EPS, a protective barrier between cells and their external environment), is essential for elucidating mercury's toxicological mechanisms. Given the inherent cell heterogeneity, a novel analysis system of an online viscoelastic fluid focusing chip-time-resolved analysis inductively coupled plasma mass spectrometry has been developed to investigate the bioaccumulation of HgS nanoparticles and Hg2+ in single Microcystis aeruginosa (M. aeruginosa) cells, exploring the interaction mechanisms between HgS/Hg2+ accumulation in algal cells and EPS. The single-cell analysis results reveal minimal bioavailability of HgS within algal cells, with mercury's toxicity to M. aeruginosa being species-dependent. Notably, algal cells exhibited more heterogeneity in HgS uptake than in Hg2+ uptake. Under Hg2+/HgS stress, M. aeruginosa cells with EPS removed (EPS-R algal cells) showed an increased level of bioaccumulation of mercury compared to those with EPS (EPS-C algal cells), highlighting the critical role of EPS in mercury bioaccumulation. Overall, the designed viscoelastic fluid microfluidic focusing chip integrates focusing and cleaning functions, featuring easy fabrication, simple operation, low sample loss, and relatively high throughput. Under the optimal conditions, the sample throughput is 1195 min-1 and the cell recovery is 90%. Besides, this research offers novel insights into the interaction mechanisms between Hg2+/HgS and EPS in microalgal cells and unveils the specific toxic effects of Hg2+/HgS on M. aeruginosa at the single-cell level, contributing to a deeper understanding of mercury's ecological and toxicological impact in aquatic environments.

Cellular senescence contributes to spontaneous repair of the rat meniscus.

Cellular senescence, traditionally associated with aging and chronic diseases, has recently been identified as a potential facilitator of tissue regeneration via a senescence-associated secretory phenotype (SASP). In rodents, the meniscus is known to regenerate spontaneously from the surrounding synovium, but the mechanism, and especially its relationship to cellular senescence, remains unclear. This study investigated the contribution of cellular senescence to spontaneous repair of the rat meniscus. We created a rat partial medial meniscectomy (pMx) model to evaluate time-course changes in regenerative tissue. Immunohistochemistry revealed marked increases in p16 expression and senescence-associated beta-galactosidase (SA-β-gal) activity in the regenerating tissue at the early phase after pMx surgery. RNA sequencing of regenerating tissues identified the upregulation of genes related to aging, extracellular matrix organization, and cell proliferation. Fluorescence staining identified high expression of SOX9, a master regulator of cartilage/meniscus development, adjacent to p16-positive cells. Invitro investigations of the effect of SASP factors on synovial fibroblasts (SFs) demonstrated that conditioned medium from senescent SFs stimulated the proliferation and chondrogenic differentiation of normal SFs. Invivo histological evaluation to determine whether selective elimination of senescent cells with a senolytic drug (ABT-263) retarded spontaneous repair of meniscus invivo confirmed that ABT-263 decreased the meniscus score and expression of SOX9, aggrecan, and type 1 collagen. Our findings indicate that transient senescent cell accumulation and SASP in regenerating tissues beneficially contribute to spontaneous repair of the rat meniscus. Further research into the molecular mechanism will provide a novel strategy for meniscus regeneration based on cellular senescence.

Application of Peptide-Conjugated Photosensitizers for Photodynamic Cancer Therapy: A Review

Photodynamic therapy (PDT) is a clinically approved therapeutic option for the treatment of various types of cancer. PDT calls for the application of photosensitizers (PSs) and photoactivation with a particular light wavelength while tissue oxygen is present. Anticancer efficacy depends on the combination of these three substrates leading to the generation of cytotoxic reactive oxygen species (ROS) that promote apoptosis, necrosis, and autophagy of cancer cells. However, one of the biggest problems with conventional PDT is the poor accumulation and targeting of PSs to tumor tissues, resulting in undesirable side effects and unfavorable therapeutic outcomes. To overcome this, new photosensitizers have been developed through bioconjugation and encapsulation with targeting molecules, such as peptides, allowing a better accumulation and targeting in tumor cells. Several studies have been conducted to test the efficacy of several peptide-conjugated photosensitizers and improve PDT efficacy. This review aims to present current insights into various types of peptide-conjugated photosensitizers, with the goal of enhancing cancer treatment efficacy, addressing the limitations of conventional PDT, and expanding potential applications in medicine.

Senescence-related genes are associated with the immunopathology signature of American Tegumentary Leishmaniasis lesions and may predict progression to mucosal leishmaniasis.

The American Tegumentary Leishmaniasis (ATL) is caused by protozoans of the genus Leishmania and varies from mild localized cutaneous leishmaniasis (LCL) form to more severe manifestations such as the diffuse cutaneous leishmaniasis (DCL) form and the mucosal leishmaniasis (ML) form. Previously, we demonstrated the accumulation of senescent cells in skin lesions of patients with LCL. Moreover, lesional transcriptomic analyses revealed a robust co-induction of senescence and pro-inflammatory gene signatures, highlighting the critical role of senescent T cells in orchestrating pathology. In this work we hypothesized that senescent cells might operate differently among the ATL spectrum, potentially influencing immunopathological mechanisms and clinical outcome. We analysed previously published RNA-Seq datasets of skin biopsies of healthy subjects and lesional skin from DCL patients, LCL patients and LCL patients that, after treatment, progressed to mucosal leishmaniasis (MLP). Our findings demonstrate a robust presence of a CD8 T cell signature associated with both LCL and MLP lesions. Moreover, both inflammatory and cytotoxic signatures were significantly upregulated, showing a strong increase in MLP and LCL groups, but not DCL. The senescence signature was elevated between LCL and MLP groups, representing the only distinguishable signature of immunopathology between them. Interestingly, our analyses further revealed the senescence signature's capacity to predict progression from LCL to mucosal forms, which was not observed with other signatures. Both the senescence-signature score and specific senescence-associated genes demonstrated an increased capacity to predict mucosal progression, with correct predictions exceeding 97% of cases. Collectively, our findings contribute to a comprehensive understanding of immunosenescence in ATL and suggest that senescence may represent the latest and most important signature of the immunopathogenisis. This highlights its potential value in predicting disease severity.

6-Gingerol Inhibits De Novo Lipogenesis by Targeting Stearoyl-CoA Desaturase to Alleviate Fructose-Induced Hepatic Steatosis.

Metabolic-associated fatty liver disease (MAFLD), also known as non-alcoholic fatty liver disease (NAFLD), is a worldwide liver disease without definitive or widely used therapeutic drugs in clinical practice. In this study, we confirm that 6-gingerol (6-G), an active ingredient of ginger (Zingiber officinale Roscoe) in traditional Chinese medicine (TCM), can alleviate fructose-induced hepatic steatosis. It was found that 6-G significantly decreased hyperlipidemia caused by high-fructose diets (HFD) in rats, and reversed the increase in hepatic de novo lipogenesis (DNL) and triglyceride (TG) levels induced by HFD, both in vivo and in vitro. Mechanistically, chemical proteomics and cellular thermal shift assay (CETSA)-proteomics approaches revealed that stearoyl-CoA desaturase (SCD) is a direct binding target of 6-G, which was confirmed by further CETSA assay and molecular docking. Meanwhile, it was found that 6-G could not alter SCD expression (in either mRNA or protein levels), but inhibited SCD activity (decreasing the desaturation levels of fatty acids) in HFD-fed rats. Furthermore, SCD deficiency mimicked the ability of 6-G to reduce lipid accumulation in HF-induced HepG2 cells, and impaired the improvement in hepatic steatosis brought about by 6-G treatment in HFD supplemented with oleic acid diet-induced SCD1 knockout mice. Taken together, our present study demonstrated that 6-G inhibits DNL by targeting SCD to alleviate fructose diet-induced hepatic steatosis.

Induction of chronic asthma up regulated the transcription of senile factors in male rats

BackgroundThe main characteristic of asthma is chronic inflammation. We examined cellular senescence by histology and molecular assay in the lungs of a rat model of asthma. This model comprises sensitization by several intraperitoneal injections of ovalbumin with aluminium hydroxide, followed by aerosol challenges every other day.ResultsData showed that asthma induction caused histological changes including, hyperemia, interstitial pneumonia, fibrinogen clots, and accumulation of inflammatory cells in the pleura. There is an elevation of IL-1β and NF-kB proteins in the asthmatic group (P < 0.001) compared to the control group. The expression of ß-galactosidase increased (P < 0.01), while the expression of Klotho and Sox2 genes was decreased in the lung tissue of the asthmatic group (P < 0.01).ConclusionTaken together, these findings suggest that asthmatic conditions accelerated the cellular senescence in the lung tissue.

Osteopontin Promotes Cholangiocyte Secretion of Chemokines to Support Macrophage Recruitment and Fibrosis in MASH.

Osteopontin (OPN) promotes the ductular reaction and is a major driver of chronic liver disease (CLD) progression. Although CLD is characterised by the accumulation of inflammatory cells including macrophages around the peri-portal regions, the influence of OPN on recruitment is unclear. We investigated the role of OPN in cholangiocyte chemokine production and macrophage recruitment by combining invivo, invitro, and in silico approaches. The effects of OPN on cholangiocyte chemokine production and macrophage migration were assessed in culture, alongside RNA-sequencing to identify genes and pathways affected by OPN depletion. Murine liver injury models were used to assess liver chemokine expression and liver macrophage/monocyte recruitment. OPN and chemokine expression were analysed in liver tissue and plasma from biopsy-proven metabolic dysfunction-associated alcoholic steatohepatitis (MASH) patients. OPN-knockdown in cholangiocytes reduced chemokine secretion. RNA-sequencing showed OPN-related effects clustered around immunity, chemotaxis and chemokine production. Macrophage exposure to cholangiocyte-conditioned media showed OPN-supported migration via chemokines chemokine (C-C motif) ligand (CCL)2, CCL5 and chemokine (C-X-C motif) ligand (CXCL)1. These effects were related to NF-κB signalling. Murine liver fibrosis was accompanied by upregulated liver OPN, CCL2, CCL5 and CXCL1 mRNA, and accumulation of liver cluster of differentiation (CD)11b/F4/80+CC chemokine receptors (CCR2)high macrophages but treatment with OPN-specific neutralising aptamers reduced fibrosis, chemokine mRNAs and accumulation of liver CD11b/F4/80+CCR2high/lymphocyte antigen 6 complexhigh inflammatory monocytes. In human MASH, liver OPN correlated with chemokines CCL2 and IL8 in association with portal injury and fibrosis. Plasma OPN, serum CCL2 and IL8 also increased with fibrosis stage. OPN promotes cholangiocyte chemokine secretion and the accumulation of pro-inflammatory monocytes. These data support neutralisation of OPN as an anti-inflammatory and anti-fibrotic strategy.

A Caspase 3‐Hijacking Nanosystem Enhances Cancer Radiotherapy by Suppressing Tumor Repopulation

AbstractRadiotherapy is used in the treatment of ≈50% of patients with cancer. However, tumor repopulation is a major cause of treatment failure after radiotherapy. It is observed that apoptotic tumor following ionizing radiation (IR) accelerated the growth of surviving tumor cells. Here a Gasdermin E and Tannic acid‐based nanoassembly (GT) loaded with manganese tetroxide (Mn3O4) (termed as Mn3O4@GT) is developed to suppress tumor repopulation and improve the treatment outcome of radiotherapy. Mn3O4@GT enables an increase in the reactive oxygen species accumulation in tumor cells, enhancing radiotherapy‐mediated tumor killing. What's more, it can hijack activated caspase 3 to induce tumor pyroptosis, reversing apoptosis‐mediated tumor repopulation. In vivo results shows that Mn3O4@GT significantly reduced the IR induced tumor repopulation by 2.7 fold, resulting in 92% complete regression of tumors. In addition, Mn3O4@GT can sensitize tumors to anti‐PD‐L1 therapy by inducing immunogenic pyroptosis with 85% regression of distant tumors. The caspase 3‐hijacking nanosystem holds a great potential for improving the clinical benefits of radiotherapy.

Klebsiella pneumoniae co-infection leads to fatal pneumonia in SARS-CoV-2-infected mice

SARS-CoV-2 patients have been reported to have high rates of secondary Klebsiella pneumoniae infections. K. pneumoniae is a commensal that is typically found in the respiratory and gastrointestinal tracts. However, it can cause severe disease when a person’s immune system is compromised. Despite a high number of K. pneumoniae cases reported in SARS-CoV-2 patients, a co-infection animal model evaluating the pathogenesis is not available. In our cohort of COVID-19-positive human patients, 38% exhibited the presence of K. pneumoniae. Therefore we developed a mouse model to study the disease pathogenesis of SARS-CoV-2 and K. pneumoniae co-infection. BALB/cJ mice were inoculated with mouse-adapted SARS-CoV-2 followed by a challenge with K. pneumoniae. Mice were monitored for body weight change, clinical signs, and survival during infection. The bacterial load, viral titers, immune cell accumulation and phenotype, and histopathology were evaluated in the lungs. The co-infected mice showed severe clinical disease and a higher mortality rate within 48 h of K. pneumoniae administration. The co-infected mice had significantly elevated bacterial load in the lungs, however, viral loads were similar between co-infected and single-infected mice. Histopathology of co-infected mice showed severe bronchointerstitial pneumonia with copious intralesional bacteria. Flow cytometry analysis showed significantly higher numbers of neutrophils and macrophages in the lungs. Collectively, our results demonstrated that co-infection of SARS-CoV-2 with K. pneumoniae causes severe disease with increased mortality in mice.

Gastrointestinal symptoms in children with mastocytosis

Introduction. Mastocytosis is a heterogeneous group of diseases characterized by the abnormal accumulation of clonal mast cells (MCs) in various tissues and organs, including skin, bone marrow, liver, spleen and lymph nodes. The clinical picture of cutaneous and indolent systemic mastocytosis is formed by a wide range of symptoms associated with activation of mast cells. Single European studies have demonstrated wide variability in the frequency of gastrointestinal symptoms (GI-symptoms)) in children with mastocytosis (from 15 to 50%).Aim. To analyze the frequency of mediator-related GI-symptoms in children with different subtypes and clinical forms of mastocytosis.Materials and methods. A prospective observational study included data from 289 children aged 3 to 17 years who were under observation at the Moscow Scientific and Practical Center of Dermatovenereology and Cosmetology. Symptoms were assessed using the Pediatric grade scale of symptoms of mastocytosis. Clinical manifestations of reactions caused by mast cell degranulation were compared with data from clinical and laboratory studies. The concentrations of tryptase and histamine in the blood serum of patients were determined. The incidence of organomegaly and mesenteric lymphadenitis in children with mediating symptoms and without symptoms was determined using ultrasound.Results. 67 (23.2%) patients had GI symptoms. More than half of the patients (51.6%) indicated abdominal pain, 32.3% reported diarrhea. The severity of pain symptoms correlated with the level of serum tryptase (ρ = 0.564, p &lt; 0.01). The incidence of hepatomegaly and mesadenitis in children with GI- symptoms was 19.4% and 25.4%, respectively. In a comparative analysis in groups of children with and without GI symptoms, the differences in the number of identified cases of organomegaly and mesadenitis were statistically significant (p &lt; 0.001). An increase in histamine levels in the blood was detected in half of the patients with complaints of heartburn and nausea.Conclusion. Our results demonstrated that a study of the level of serum tryptase, ultrasound of the abdominal organs and lymph nodes should be carried out in all children with mediator-related GI-symptoms regardless of the clinical form of mastocytosis.

Phosphatidylserine phospholipase A1 enables GPR34-dependent immune cell accumulation in the peritoneal cavity.

The peritoneal cavity (PerC) is an important site for immune responses to infection and cancer metastasis. Yet few ligand-receptor axes are known to preferentially govern immune cell accumulation in this compartment. GPR34 is a lysophosphatidylserine (lysoPS)-responsive receptor that frequently harbors gain-of-function mutations in mucosa-associated B cell lymphoma. Here, we set out to test the impact of a GPR34 knock-in (KI) allele in the B-lineage. We report that GPR34 KI promotes the PerC accumulation of plasma cells (PC) and memory B cells (MemB). These KI cells migrate robustly to lysoPS ex vivo, and the KI allele synergizes with a Bcl2 transgene to promote MemB but not PC accumulation. Gene expression and labeling studies reveal that GPR34 KI enhances PerC MemB proliferation. Both KI PC and MemB are specifically enriched at the omentum, a visceral adipose tissue containing fibroblasts that express the lysoPS-generating PLA1A enzyme. Adoptive transfer and chimera experiments revealed that KI PC and MemB maintenance in the PerC is dependent on stromal PLA1A. These findings provide in vivo evidence that PLA1A produces lysoPS that can regulate GPR34-mediated immune cell accumulation at the omentum.

STYK1 mediates NK cell anti-tumor response through regulating CCR2 and trafficking

The serine/threonine/tyrosine kinase 1 (STYK1) is a receptor protein-tyrosine kinase (RPTK)-like molecule that is detected in several human organs. STYK1 plays an important role in promoting tumorigenesis and metastasis in various cancers. By analyzing the expression of RTKs in immune cells in the database of 2013 Immunological Genome Project, we found that STYK1 was principally expressed in NK cells. In order to investigate the function of STYK1, we used CRISPR/Cas9 technology to generate STYK1-deleted mice, we found STYK1 deletion mice have normal number, development, and function of NK cells in spleen and bone marrow in tumor-free resting state. To examine the tumor surveillance of STYK1 in vivo, we utilized a variety of tumor models, including NK cell-specific target cell (ß2M and RMA-S) clearance experiments in vivo, subcutaneous and intravenous injection of B16F10 melanoma model, and the spontaneous breast cancer model MMTV-PyMT. Surprisingly, we discovered that deletion of the oncogenic STYK1 promoted the four-model tumor progression, and we observed a reduction of NK cell accumulation in the tumor tissues of STYK1 deletion mice compared to WT mice. In order to study the mechanism of STYK1 in NK, RNA sequence of STYK1−/− and WT NK have unveiled a disparity in the signaling pathways linked to migration and adhesion in STYK1−/− NK cells. Further analysis of chemokine receptors associated with NK cell migration revealed that STYK1-deficient NK cells exhibited a significant reduction in CCR2 expression. The STYK1 expression was negatively associated with tumor progression in glioma patients. Overall, our study found the expression of STYK1 in NK cell mediates NK cell anti-tumor response through regulating CCR2 and infiltrating into tumor tissue.