Modulation of Inflammation by Extracellular Granzyme A

Distinct cell death pathways induced by granzymes collectively protect against intestinal Salmonella infection

Intestinal intraepithelial T lymphocytes (IEL) constitutively express high amounts of the cytotoxic proteases Granzymes (Gzm) A and B and are therefore thought to protect the intestinal epithelium against infection by killing infected epithelial cells. However, the role of IEL granzymes in a protective immune response has yet to be demonstrated. We show that GzmA and GzmB are required to protect mice against oral, but not intravenous, infection with Salmonella enterica serovar Typhimurium, consistent with an intestine-specific role. IEL-intrinsic granzymes mediate the protective effects by controlling intracellular bacterial growth and aiding in cell-intrinsic pyroptotic cell death of epithelial cells. Surprisingly, we found that both granzymes play non-redundant roles. GzmB-/- mice carried significantly lower burdens of Salmonella, as predominant GzmA-mediated cell death effectively reduced bacterial translocation across the intestinal barrier. Conversely, in GzmA-/- mice, GzmB-driven apoptosis favored luminal Salmonella growth by providing nutrients, while still reducing translocation across the epithelial barrier. Together, the concerted actions of both GzmA and GzmB balance cell death mechanisms at the intestinal epithelium to provide optimal control that Salmonella cannot subvert.

The Mechanism of Pyroptosis and Its Application Prospect in Diabetic Wound Healing

Pyroptosis defines a form of pro-inflammatory-dependent programmed cell death triggered by gasdermin proteins, which creates cytoplasmic pores and promotes the activation and accumulation of immune cells by releasing several pro-inflammatory mediators and immunogenic substances upon cell rupture. Pyroptosis comprises canonical (mediated by Caspase-1) and non-canonical (mediated by Caspase-4/5/11) molecular signaling pathways. Numerous studies have explored the contributory roles of inflammasome and pyroptosis in the progression of multiple pathological conditions such as tumors, nerve injury, inflammatory diseases and metabolic disorders. Accumulating evidence indicates that the activation of the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome results in the activation of pyroptosis and inflammation. Current evidence suggests that pyroptosis-dependent cell death plays a progressive role in the development of diabetic complications including diabetic wound healing (DWH) and diabetic foot ulcers (DFUs). This review presents a brief overview of the molecular mechanisms underlying pyroptosis and addresses the current research on pyroptosis-dependent signaling pathways in the context of DWH. In this review, we also present some prospective therapeutic compounds/agents that can target pyroptotic signaling pathways, which may serve as new strategies for the effective treatment and management of diabetic wounds.

Gene Expression Profile Analysis of the Molecular Mechanism of HOXD10 Regulation of Epithelial Ovarian Cancer Cells

Epithelial ovarian cancer (EOC) is the most common type of ovarian cancer. Although studies have reported that downregulation of HOXD10 expression may contribute to the migration and invasion abilities in EOC, much about its regulation remains to be fully elucidated. The present study aimed to identify different gene expression profiles associated with HOXD10 overexpression in EOC cells. The present study confirmed that HOXD10 overexpression effectively inhibited the proliferation and motility of the TOV21G and TOV112D cells. Further, we overexpress HOXD10 in TOV112D cells, the different gene expression (DEGs) profiles induce by HOXD10 was analyze by the Human OneArray microarray. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), ingenuity pathway analysis (IPA) was used to perform the pathway enrichment analysis for the DEGs. Integrated bioinformatics analysis showed that the DEGs were enriched for terms related to oxidative phosphorylation and mitochondrial function pathways. Dysfunction oxidative phosphorylation metabolic pathway occurs frequently in many tumors. We validated the expression of NDUFA7, UQCRB and CCL2 using qPCR, involving in metabolism-related pathway, were significantly changed by HOXD10 overexpression in EOC. The detailed regulatory mechanism that links HOXD10 and the oxidative phosphorylation genes is not yet fully understood, our findings provide novel insight into HOXD10-mediated pathways and their effects on cancer metabolism, carcinogenesis, and the progression of EOC. Thus, the data suggest that strategies to interfere with metabolism-related pathways associated with cancer drug resistance could be considered for the treatment of ovarian tumors.

The USP7-STAT3-granzyme-Par-1 axis regulates allergic inflammation by promoting differentiation of IL-5-producing Th2 cells

Uncontrolled type 2 immunity by type 2 helper T (Th2) cells causes intractable allergic diseases; however, whether the interaction of CD4+ T cells shapes the pathophysiology of allergic diseases remains unclear. We identified a subset of Th2 cells that produced the serine proteases granzyme A and B early in differentiation. Granzymes cleave protease-activated receptor (Par)-1 and induce phosphorylation of p38 mitogen-activated protein kinase (MAPK), resulting in the enhanced production of IL-5 and IL-13 in both mouse and human Th2 cells. Ubiquitin-specific protease 7 (USP7) regulates IL-4-induced phosphorylation of STAT3, resulting in granzyme production during Th2 cell differentiation. Genetic deletion of Usp7 or Gzma and pharmacological blockade of granzyme B ameliorated allergic airway inflammation. Furthermore, PAR-1+ and granzyme+ Th2 cells were colocalized in nasal polyps from patients with eosinophilic chronic rhinosinusitis. Thus, the USP7-STAT3-granzymes-Par-1 pathway is a potential therapeutic target for intractable allergic diseases.

Recent updates on pyroptosis in tumors of the digestive tract

Pyroptosis is an inflammasome-dependent form of programmed cell death that is mediated by caspases-1, -4, -5, and -11, and the gasdermin protein family. It is characterized by the rupture of cell membrane and the subsequent release of cell contents and interleukins, leading to inflammatory reaction and activation of the immune system. Recent studies have suggested that pyroptosis plays a role in the development of gastrointestinal tumors, impeding tumor generation and progression as well as providing a favorable microenvironment for tumor growth. In this review we outlined the current knowledge regarding the implications of pyroptosis in gastrointestinal cancers.

Relevance of tissue-resident memory CD8 T cells in the onset of Parkinson's disease and examination of its possible etiologies: infectious or autoimmune?

Tissue-resident memory CD8 T cells are responsible for local immune surveillance in different tissues, including the brain. They constitute the first line of defense against pathogens and cancer cells and play a role in autoimmunity. A recently published study demonstrated that CD8 T cells with markers of residency containing distinct granzymes and interferon-γ infiltrate the parenchyma of the substantia nigra and contact dopaminergic neurons in an early premotor stage of Parkinson's disease. This infiltration precedes α-synuclein aggregation and neuronal loss in the substantia nigra, suggesting a relevant role for CD8 T cells in the onset of the disease. To date, the nature of the antigen that initiates the adaptive immune response remains unknown. This review will discuss the role of tissue-resident memory CD8 T cells in brain immune homeostasis and in the onset of Parkinson's disease and other neurological diseases. We also discuss how aging and genetic factors can affect the CD8 T cell immune response and how animal models can be misleading when studying human-related immune response. Finally, we speculate about a possible infectious or autoimmune origin of Parkinson's disease.

CRISPR/Cas13d targeting GZMA in PARs pathway regulates the function of osteoclasts in chronic apical periodontitis

Chronic apical periodontitis is a prevalent oral disease characterized by bone loss, and its underlying mechanisms remain unclear. This study aimed to investigate the role and mechanism of the serine protease GZMA in osteoclasts during chronic apical periodontitis. To address this, we employed crRNA/Cas13d to inhibit GZMA expression and examined its impact on osteoclast behavior. Our findings revealed that GZMA plays a significant role in promoting osteoclast cell proliferation while inhibiting cell apoptosis. Additionally, the inhibition of GZMA led to a notable increase in miR-25-3p expression, which, in turn, downregulated the expression of TGF-β. Consequently, the reduction in TGF-β expression led to a decrease in PAR1 expression within the PARs pathway. These results suggest that GZMA might serve as a promising therapeutic target for the treatment of chronic apical periodontitis. Furthermore, our study highlights the potential of targeting GZMA using crRNA/Cas13d as a valuable approach for future therapeutic interventions.

Comparative transcriptomics of porcine liver-resident CD8αdim, liver CD8αhigh and circulating blood CD8αhigh NK cells reveals an intermediate phenotype of liver CD8αhigh NK cells

Liver-resident NK (lrNK) cells have been studied in humans as well as in mice. Unfortunately, important differences have been observed between murine and human lrNK cells, complicating the extrapolation of data obtained in mice to man. We previously described two NK cell subsets in the porcine liver: A CD8αhigh subset, with a phenotype much like conventional CD8αhigh NK cells found in the peripheral blood, and a specific liver-resident CD8αdim subset which phenotypically strongly resembles human lrNK cells. These data suggest that the pig might be an attractive model for studying lrNK cell biology. In the current study, we used RNA-seq to compare the transcriptome of three porcine NK cell populations: Conventional CD8αhigh NK cells from peripheral blood (cNK cells), CD8αhigh NK cells isolated from the liver, and the liver-specific CD8αdim NK cells. We found that highly expressed transcripts in the CD8αdim lrNK cell population mainly include genes associated with the (adaptive) immune response, whereas transcripts associated with cell migration and extravasation are much less expressed in this subset compared to cNK cells. Overall, our data indicate that CD8αdim lrNK cells show an immature and anti-inflammatory phenotype. Interestingly, we also observed that the CD8αhigh NK cell population that is present in the liver appears to represent a population with an intermediate phenotype. Indeed, while the transcriptome of these cells largely overlaps with that of cNK cells, they also express transcripts associated with liver residency, in particular CXCR6. The current, in-depth characterization of the transcriptome of porcine liver NK cell populations provides a basis to use the pig model for research into liver-resident NK cells.

Smart probes for optical imaging of T cells and screening of anti-cancer immunotherapies

T cells are an essential part of the immune system with crucial roles in adaptive response and the maintenance of tissue homeostasis. Depending on their microenvironment, T cells can be differentiated into multiple states with distinct functions. This myriad of cellular activities have prompted the development of numerous smart probes, ranging from small molecule fluorophores to nanoconstructs with variable molecular architectures and fluorescence emission mechanisms. In this Tutorial Review, we summarize recent efforts in the design, synthesis and application of smart probes for imaging T cells in tumors and inflammation sites by targeting metabolic and enzymatic biomarkers as well as specific surface receptors. Finally, we briefly review current strategies for how smart probes are employed to monitor the response of T cells to anti-cancer immunotherapies. We hope that this Review may help chemists, biologists and immunologists to design the next generation of molecular imaging probes for T cells and anti-cancer immunotherapies.

Dynamic Intestinal Stem Cell Plasticity and Lineage Remodeling by a Nutritional Environment Relevant to Human Risk for Tumorigenesis

New Western-style diet 1 (NWD1), a purified diet establishing mouse exposure to key nutrients recapitulating levels that increase human risk for intestinal cancer, reproducibly causes mouse sporadic intestinal and colonic tumors reflecting human etiology, incidence, frequency, and lag with developmental age. Complex NWD1 stem cell and lineage reprogramming was deconvolved by bulk and single-cell RNA sequencing, single-cell Assay for Transposase-Accessible Chromatin using sequencing, functional genomics, and imaging. NWD1 extensively, rapidly, and reversibly, reprogrammed Lgr5hi stem cells, epigenetically downregulating Ppargc1a expression, altering mitochondrial structure and function. This suppressed Lgr5hi stem cell functions and developmental maturation of Lgr5hi cell progeny as cells progressed through progenitor cell compartments, recapitulated by Ppargc1a genetic inactivation in Lgr5hi cells in vivo. Mobilized Bmi1+, Ascl2hi cells adapted lineages to the nutritional environment and elevated antigen processing and presentation pathways, especially in mature enterocytes, causing chronic, protumorigenic low-level inflammation. There were multiple parallels between NWD1 remodeling of stem cells and lineages with pathogenic mechanisms in human inflammatory bowel disease, also protumorigenic. Moreover, the shift to alternate stem cells reflects that the balance between Lgr5-positive and -negative stem cells in supporting human colon tumors is determined by environmental influences. Stem cell and lineage plasticity in response to nutrients supports historic concepts of homeostasis as a continual adaptation to environment, with the human mucosa likely in constant flux in response to changing nutrient exposures.

IMPLICATIONS

Although oncogenic mutations provide a competitive advantage to intestinal epithelial cells in clonal expansion, the competition is on a playing field dynamically sculpted by the nutritional environment, influencing which cells dominate in mucosal maintenance and tumorigenesis.

Extended cleavage specificities of human granzymes A and K, two closely related enzymes with conserved but still poorly defined functions in T and NK cell-mediated immunity

Granzymes A and K are two highly homologous serine proteases expressed by mammalian cytotoxic T cells (CTL) and natural killer cells (NK). Granzyme A is the most abundant of the different granzymes (gzms) expressed by these two cell types. Gzms A and K are found in all jawed vertebrates and are the most well conserved of all hematopoietic serine proteases. Their potential functions have been studied extensively for many years, however, without clear conclusions. Gzm A was for many years thought to serve as a key component in the defense against viral infection by the induction of apoptosis in virus-infected cells, similar to gzm B. However, later studies have questioned this role and instead indicated that gzm A may act as a potent inducer of inflammatory cytokines and chemokines. Gzms A and K form clearly separate branches in a phylogenetic tree indicating separate functions. Transcriptional analyses presented here demonstrate the presence of gzm A and K transcripts in both CD4⁺ and CD8⁺ T cells. To enable screening for their primary biological targets we have made a detailed analysis of their extended cleavage specificities. Phage display analysis of the cleavage specificity of the recombinant enzymes showed that both gzms A and K are strict tryptases with high selectivity for Arg over Lys in the P1 position. The major differences in the specificities of these two enzymes are located N-terminally of the cleavage site, where gzm A prefers small amino acids such as Gly in the P3 position and shows a relatively relaxed selectivity in the P2 position. In contrast, gzm K prefers large amino acids such as Phe, Tyr, and Trp in both the P2 and P3 positions and does not tolerate negatively charged residues in the P2 position. This major distinction in extended specificities is likely reflected also in preferred in vivo targets of these two enzymes. This information can now be utilized for high-precision screening of primary targets for gzms A and K in search of their highly conserved but still poorly defined functions in vertebrate immunity.

Cord blood-derived Vδ2+ and Vδ2- T cells acquire differential cell state compositions upon in vitro expansion

Human cord blood-derived γδ T cells (CBγδ) display a highly diverse TCRγδ repertoire and have a unique subtype composition different from fetal or adult peripheral blood counterparts. We expanded CBγδ in vitro using an irradiated Epstein-Barr virus-transformed feeder cell-based modified rapid expansion protocol (REP). Single-cell RNA sequencing tracked progressive differentiation of naïve CBγδ into cells expressing neoantigen-reactive tumor-infiltrating lymphocyte as well as tissue-resident memory precursor-like and antigen-presenting cell-like gene signatures. TCRγδ clonal tracing revealed a bias toward cytotoxic effector differentiation in a much larger proportion of Vδ2- clones compared to Vδ2+ clones, resulting in the former being more cytotoxic at the population level. These clonotype-specific differentiation dynamics were not restricted to REP and were recapitulated upon secondary nonviral antigen stimulations. Thus, our data showed intrinsic cellular differences between major subtypes of human γδ T cells already in operation at early postnatal stage and highlighted key areas of consideration in optimizing cell manufacturing processes.

Crosstalk between apoptosis and cytotoxic lymphocytes (CTLs) in the course of Lagovirus europaeus GI.1a infection in rabbits

Introduction

Lagovirus europaeus is a single-stranded RNA virus causing an acute fatal disease in wild and domestic rabbits around the world. Studies have shown that the pivotal process impacting the immune response against the disease is apoptosis, registered mainly in hepatocytes and in peripheral blood, together with an increased number of cytotoxic lymphocytes (CTLs). It is known that cytotoxic lymphocytes can induce target cells to undergo apoptosis on the pseudoreceptor pathway, such apoptosis having been found in several acute and chronic viral infections. The study aimed to assess the crosstalk between the apoptosis of peripheral blood lymphocytes and CD8+ T lymphocytes (as CTLs) in rabbits infected with 6 Lagovirus europaeus GI.1a viruses.

Material and Methods

Sixty rabbits of Polish hybrid breed comprising both sexes and weighing 3.2–4.2 kg were the experimental group, and an identical group was the control. Each of the six GI.1a Lagovirus europaeus viruses was inoculated into ten experimental rabbits. Control rabbits received glycerol as a placebo. Flow cytometric analysis was performed on blood from the study and control group animals for peripheral blood lymphocyte apoptosis and CTL percentage determination.

Results

The activation of apoptosis in peripheral blood lymphocytes was recorded from 4 h post inoculation (p.i.) up to 36 h p.i. The percentage of CTLs in the total blood pool decreased from 8 to 36 h p.i. A negative correlation between apoptosis of lymphocytes and the number of CTLs was proven.

Conclusion

This may be the first evidence of virus-induced CTL apoptosis in Lagovirus europaeus GI.1a infection.

Beyond target cell death - Granzyme serine proteases in health and disease

Granzymes are a family of small (∼32 kDa) serine proteases with a range of substrate specificities that are stored in, and released from, the cytoplasmic secretory vesicles ('granules') of cytotoxic T lymphocytes and natural killer cells. Granzymes are not digestive proteases but finely tuned processing enzymes that target their substrates in specific ways to activate various signalling pathways, or to inactivate viral proteins and other targets. Great emphasis has been placed on studying the pro-apoptotic functions of granzymes, which largely depend on their synergy with the pore-forming protein perforin, on which they rely for penetration into the target cell cytosol to access their substrates. While a critical role for granzyme B in target cell apoptosis is undisputed, both it and the remaining granzymes also influence a variety of other biological processes (including important immunoregulatory functions), which are discussed in this review. This includes the targeting of many extracellular as well as intracellular substrates, and can also lead to deleterious outcomes for the host if granzyme expression or function are dysregulated or abrogated. A final important consideration is that granzyme repertoire, biochemistry and function vary considerably across species, probably resulting from the pressures applied by viruses and other pathogens across evolutionary time. This has implications for the interpretation of granzyme function in preclinical models of disease.

Hemizygous Granzyme A Mice Expressing the hSOD1G93A Transgene Show Slightly Extended Lifespan

Granzyme A (gzmA), a serine protease involved in the modulation of the inflammatory immune response, is found at an elevated level in the serum from ALS patients. However, the influence of gzmA on the progression of ALS remains unclear. The aim of our work was to assess whether the absence of gzmA in an ALS murine model could help slow down the progression of the disease. Homozygous and hemizygous gzmA-deficient mice expressing the hSOD1G93A transgene were generated, and survival of these mice was monitored. Subsequently, gene and protein expression of inflammatory and oxidative stress markers was measured in the spinal cord and quadriceps of these mice. We observed the longest lifespan in gzmA+/- mice. GzmA gene and protein expression was downregulated in the spinal cord and serum from gmzA+/- mice, confirming that the increased survival of hemizygous mice is correlated with lower levels of gzmA. In addition, mRNA and protein levels of glutathione reductase (GSR), involved in oxidative stress, were found downregulated in the spinal cord and quadriceps of gmzA+/- mice, together with lower IL-1β and IL-6 mRNA levels in hemyzigous mice. In summary, our findings indicate for the first time that reduced levels, but not the absence, of gzmA could slightly ameliorate the disease progression in this animal model.

Regulation of Progression and Resolution of Liver Fibrosis by Immune Cells

The excessive accumulation of extracellular matrix proteins results in fibrosis-a condition implicated in several diseased conditions, such as nonalcoholic steatohepatitis, viral hepatitis, and autoimmune hepatitis. Despite its prevalence, direct and effective treatments for fibrosis are lacking, warranting the development of better therapeutic strategies. Accumulating evidence has shown that liver fibrosis-a condition previously considered irreversible-is reversible in specific conditions. Immune cells residing in or infiltrating the liver (e.g., macrophages) are crucial in the pathogenesis of fibrosis. Given this background, the roles and action mechanisms of various immune cells and their subsets in the progression and recovery of liver fibrosis, particularly concerning nonalcoholic steatohepatitis, are discussed in this review. Furthermore, the development of better therapeutic strategies based on stage-specific properties and using advanced techniques as well as the mechanisms underlying recovery are elaborated. In conclusion, we consider the review comprehensively provides the present achievements and future possibilities revolving around fibrosis treatment.

Noncytotoxic Roles of Granzymes in Health and Disease

Granzymes are serine proteases previously believed to play exclusive and somewhat redundant roles in lymphocyte-mediated target cell death. However, recent studies have challenged this paradigm. Distinct substrate profiles and functions have since emerged for each granzyme while their dysregulated proteolytic activities have been linked to diverse pathologies.

Characterization of NKG2-A/-C, Kir and CD57 on NK Cells Stimulated with pp65 and IE-1 Antigens in Patients Awaiting Lung Transplant

Introduction: Cytomegalovirus (CMV) is the leading opportunistic infection in lung transplant (LTx) recipients. CMV is associated with graft failure and decreased survival. Recently, new antiviral therapies have been proposed. The present study aimed to investigate NK and T cell subsets of patients awaiting LTx. We analyzed the cellular populations between reactive and non-reactive QuantiFERON (QF) CMV patients for the prediction of immunological response to infection. Methods: Seventeen pre-LTx patients and 15 healthy controls (HC) have been enrolled. QF and IFN-γ ELISA assay detections were applied. NK cell subsets and T cell and proliferation assay were detected before and after stimulation with pp-65 and IE-1 CMV antigens after stratification as QF+ and QF−. Furthermore, we quantified the serum concentrations of NK− and T-related cytokines by bead-based multiplex analysis. Results: CD56^brCD16^lowNKG2A⁺KIR⁺ resulted in the best discriminatory cellular subsets between pre-LTx and HC. Discrepancies emerged between serology and QF assay. Better proliferative capability emerged from patients who were QF+, in particular in CD8 and CD25-activated cells. CD56^brCD16^low, adaptive/memory-like NK and CD8Teff were highly increased only in QF+ patients. Conclusions: QF more than serology is useful in the detection of patients able to respond to viral infection. This study provides new insights in terms of immunological responses to CMV in pre-LTX patients, particularly in NK and T cells biology.

eNAMPT Neutralization Preserves Lung Fluid Balance and Reduces Acute Renal Injury in Porcine Sepsis/VILI-Induced Inflammatory Lung Injury

Background: Numerous potential ARDS therapeutics, based upon preclinical successful rodent studies that utilized LPS challenge without mechanical ventilation, have failed in Phase 2/3 clinical trials. Recently, ALT-100 mAb, a novel biologic that neutralizes the TLR4 ligand and DAMP, eNAMPT (extracellular nicotinamide phosphoribosyltransferase), was shown to reduce septic shock/VILI-induced porcine lung injury when delivered 2 h after injury onset. We now examine the ALT-100 mAb efficacy on acute kidney injury (AKI) and lung fluid balance in a porcine ARDS/VILI model when delivered 6 h post injury.

Methods/Results: Compared to control PBS-treated pigs, exposure of ALT-100 mAb-treated pigs (0.4 mg/kg, 2 h or 6 h after injury initiation) to LPS-induced pneumonia/septic shock and VILI (12 h), demonstrated significantly diminished lung injury severity (histology, BAL PMNs, plasma cytokines), biochemical/genomic evidence of NF-kB/MAP kinase/cytokine receptor signaling, and AKI (histology, plasma lipocalin). ALT-100 mAb treatment effectively preserved lung fluid balance reflected by reduced BAL protein/tissue albumin levels, lung wet/dry tissue ratios, ultrasound-derived B lines, and chest radiograph opacities. Delayed ALT-100 mAb at 2 h was significantly more protective than 6 h delivery only for plasma eNAMPT while trending toward greater protection for remaining inflammatory indices. Delayed ALT-100 treatment also decreased lung/renal injury indices in LPS/VILI-exposed rats when delivered up to 12 h after LPS.

Conclusions: These studies indicate the delayed delivery of the eNAMPT-neutralizing ALT-100 mAb reduces inflammatory lung injury, preserves lung fluid balance, and reduces multi-organ dysfunction, and may potentially address the unmet need for novel therapeutics that reduce ARDS/VILI mortality.

Effective Natural Killer Cell Degranulation Is an Essential Key in COVID-19 Evolution

NK degranulation plays an important role in the cytotoxic activity of innate immunity in the clearance of intracellular infections and is an important factor in the outcome of the disease. This work has studied NK degranulation and innate immunological profiles and functionalities in COVID-19 patients and its association with the severity of the disease. A prospective observational study with 99 COVID-19 patients was conducted. Patients were grouped according to hospital requirements and severity. Innate immune cell subpopulations and functionalities were analyzed. The profile and functionality of innate immune cells differ between healthy controls and severe patients; CD56dim NK cells increased and MAIT cells and NK degranulation rates decreased in the COVID-19 subjects. Higher degranulation rates were observed in the non-severe patients and in the healthy controls compared to the severe patients. Benign forms of the disease had a higher granzymeA/granzymeB ratio than complex forms. In a multivariate analysis, the degranulation capacity resulted in a protective factor against severe forms of the disease (OR: 0.86), whereas the permanent expression of NKG2D in NKT cells was an independent risk factor (OR: 3.81; AUC: 0.84). In conclusion, a prompt and efficient degranulation functionality in the early stages of infection could be used as a tool to identify patients who will have a better evolution.

Cytosolic Protein Delivery Using Modular Biotin-Streptavidin Assembly of Nanocomposites

Current strategies for the delivery of proteins into cells face general challenges of endosomal entrapment and concomitant degradation of protein cargo. Efficient delivery directly to the cytosol overcomes this obstacle: we report here the use of biotin-streptavidin tethering to provide a modular approach to the generation of nanovectors capable of a cytosolic delivery of biotinylated proteins. This strategy uses streptavidin to organize biotinylated protein and biotinylated oligo(glutamate) peptide into modular complexes that are then electrostatically self-assembled with a cationic guanidinium-functionalized polymer. The resulting polymer-protein nanocomposites demonstrate efficient cytosolic delivery of six biotinylated protein cargos of varying size, charge, and quaternary structure. Retention of protein function was established through efficient cell killing via delivery of the chemotherapeutic enzyme granzyme A. This platform represents a versatile and modular approach to intracellular delivery through the noncovalent tethering of multiple components into a single delivery vector.

Granzymes-Their Role in Colorectal Cancer

Colorectal cancer (CRC) is among the most common malignancies worldwide. CRC is considered a heterogeneous disease due to various clinical symptoms, biological behaviours, and a variety of mutations. A number of studies demonstrate that as many as 50% of CRC patients have distant metastases at the time of diagnosis. However, despite the fact that social and medical awareness of CRC has increased in recent years and screening programmes have expanded, there is still an urgent need to find new diagnostic tools for early detection of CRC. The effectiveness of the currently used classical tumour markers in CRC diagnostics is very limited. Therefore, new proteins that play an important role in the formation and progression of CRC are being sought. A number of recent studies show the potential significance of granzymes (GZMs) in carcinogenesis. These proteins are released by cytotoxic lymphocytes, which protect the body against viral infection as well specific signalling pathways that ultimately lead to cell death. Some studies suggest a link between GZMs, particularly the expression of Granzyme A, and inflammation. This paper summarises the role of GZMs in CRC pathogenesis through their involvement in the inflammatory process. Therefore, it seems that GZMs could become the focus of research into new CRC biomarkers.

Homotypic fibrillization of TMEM106B across diverse neurodegenerative diseases

Misfolding and aggregation of disease-specific proteins, resulting in the formation of filamentous cellular inclusions, is a hallmark of neurodegenerative disease with characteristic filament structures, or conformers, defining each proteinopathy. Here we show that a previously unsolved amyloid fibril composed of a 135 amino acid C-terminal fragment of TMEM106B is a common finding in distinct human neurodegenerative diseases, including cases characterized by abnormal aggregation of TDP-43, tau, or α-synuclein protein. A combination of cryoelectron microscopy and mass spectrometry was used to solve the structures of TMEM106B fibrils at a resolution of 2.7 Å from postmortem human brain tissue afflicted with frontotemporal lobar degeneration with TDP-43 pathology (FTLD-TDP, n = 8), progressive supranuclear palsy (PSP, n = 2), or dementia with Lewy bodies (DLB, n = 1). The commonality of abundant amyloid fibrils composed of TMEM106B, a lysosomal/endosomal protein, to a broad range of debilitating human disorders indicates a shared fibrillization pathway that may initiate or accelerate neurodegeneration.

Widespread discrepancy in Nnt genotypes and genetic backgrounds complicates granzyme A and other knockout mouse studies

Granzyme A (GZMA) is a serine protease secreted by cytotoxic lymphocytes, with Gzma-/- mouse studies having informed our understanding of GZMA's physiological function. We show herein that Gzma-/- mice have a mixed C57BL/6J and C57BL/6N genetic background and retain the full-length nicotinamide nucleotide transhydrogenase (Nnt) gene, whereas Nnt is truncated in C57BL/6J mice. Chikungunya viral arthritis was substantially ameliorated in Gzma-/- mice; however, the presence of Nnt and the C57BL/6N background, rather than loss of GZMA expression, was responsible for this phenotype. A new CRISPR active site mutant C57BL/6J GzmaS211A mouse provided the first insights into GZMA's bioactivity free of background issues, with circulating proteolytically active GZMA promoting immune-stimulating and pro-inflammatory signatures. Remarkably, k-mer mining of the Sequence Read Archive illustrated that ≈27% of Run Accessions and ≈38% of BioProjects listing C57BL/6J as the mouse strain had Nnt sequencing reads inconsistent with a C57BL/6J genetic background. Nnt and C57BL/6N background issues have clearly complicated our understanding of GZMA and may similarly have influenced studies across a broad range of fields.

Infection of Galleria mellonella (Lepidoptera) Larvae With the Entomopathogenic Fungus Conidiobolus coronatus (Entomophthorales) Induces Apoptosis of Hemocytes and Affects the Concentration of Eicosanoids in the Hemolymph

Apoptosis and autophagy, the mechanisms of programmed cell death, play critical roles in physiological and pathological processes in both vertebrates and invertebrates. Apoptosis is also known to play an important role in the immune response, particularly in the context of entomopathogenic infection. Of the factors influencing the apoptotic process during infection, two of the lesser known groups are caspases and eicosanoids. The aim of this study was to determine whether infection by the entomopathogenic soil fungus Conidiobolus coronatus is associated with apoptosis and changes in caspase activity in the hemocytes of Galleria mellonella larvae, and to confirm whether fungal infection may affect eicosanoid levels in the host. Larvae were exposed for 24 h to fully grown and sporulating fungus. Hemolymph was collected either immediately after termination of exposure (F24 group) or 24 h later (F48 group). Apoptosis/necrosis tests were performed in hemocytes using fluorescence microscopy and flow cytometry, while ELISA tests were used to measure eicosanoid levels. Apoptosis and necrosis occurred to the same degree in F24, but necrosis predominated in F48. Fungal infection resulted in caspase activation, increased PGE1, PGE2, PGA1, PGF2α, and 8-iso-PGF2α levels and decreased TXB2 levels, but had no effect on TXA2 or 11-dehydro-TXB2 concentrations. In addition, infected larvae demonstrated significantly increased PLA2 activity, known to be involved in eicosanoid biosynthesis. Our findings indicate that fungal infection simultaneously induces apoptosis in insects and stimulates general caspase activity, and this may be correlated with changes in the concentrations of eicosanoids.

A Novel Pyroptosis-Related Signature for Predicting Prognosis and Indicating Immune Microenvironment Features in Osteosarcoma

Osteosarcoma is a common malignant bone tumor with a propensity for drug resistance, recurrence, and metastasis. A growing number of studies have elucidated the dual role of pyroptosis in the development of cancer, which is a gasdermin-regulated novel inflammatory programmed cell death. However, the interaction between pyroptosis and the overall survival (OS) of osteosarcoma patients is poorly understood. This study aimed to construct a prognostic model based on pyroptosis-related genes to provide new insights into the prognosis of osteosarcoma patients. We identified 46 differentially expressed pyroptosis-associated genes between osteosarcoma tissues and normal control tissues. A total of six risk genes affecting the prognosis of osteosarcoma patients were screened to form a pyroptosis-related signature by univariate and LASSO regression analysis and verified using GSE21257 as a validation cohort. Combined with other clinical characteristics, including age, gender, and metastatic status, we found that the pyroptosis-related signature score, which we named “PRS-score,” was an independent prognostic factor for patients with osteosarcoma and that a low PRS-score indicated better OS and a lower risk of metastasis. The result of ssGSEA and ESTIMATE algorithms showed that a lower PRS-score indicated higher immune scores, higher levels of tumor infiltration by immune cells, more active immune function, and lower tumor purity. In summary, we developed and validated a pyroptosis-related signature for predicting the prognosis of osteosarcoma, which may contribute to early diagnosis and immunotherapy of osteosarcoma.

In Vivo Measurement of Granzyme Proteolysis from Activated Immune Cells with PET

The biology of human granzymes remains enigmatic in part due to our inability to probe their functions outside of in vitro assays or animal models with divergent granzyme species. We hypothesize that the biology of human granzymes could be better elaborated with a translational imaging technology to reveal the contexts in which granzymes are secreted and biochemically active in vivo. Here, we advance toward this goal by engineering a Granzyme targeting Restricted Interaction Peptide specific to family member B (GRIP B) to measure secreted granzyme B (GZMB) biochemistry with positron emission tomography. A proteolytic cleavage of 64Cu-labeled GRIP B liberates a radiolabeled form of Temporin L, which sequesters the radioisotope by binding to adjacent phospholipid bilayers. Thus, at extended time points postinjection (i.e., hours, not seconds), tissue biodistribution of the radioisotope in vivo reflects relative units of the GZMB activity. As a proof of concept, we show in three syngeneic mouse cancer models that 64Cu-GRIP B detects GZMB from T cells activated with immune checkpoint inhibitors (CPI). Remarkably, the radiotracer detects the proteolysis within tumors but also in lymphoid tissue, where immune cells are activated by a systemic CPI. Control experiments with an uncleavable analogue of 64Cu-GRIP B and tumor imaging studies in germline GZMB knockout mice were applied to show that 64Cu-GRIP B is specific for GZMB proteolysis. Furthermore, we explored a potential noncytotoxic function for GZMB by applying 64Cu-GRIP B to a model of pulmonary inflammation. In summary, we demonstrate that granzyme biochemistry can be assessed in vivo using an imaging modality that can be scaled vertically into human subjects.

Identification of immune related cells and crucial genes in the peripheral blood of ankylosing spondylitis by integrated bioinformatics analysis

Background

Ankylosing spondylitis (AS) is a progressive rheumatic disease and studies reveal that the immune system is critical for the pathogenesis of AS. In the present study, various bioinformatics analysis methods were comprehensively applied, designed to identify potential key genes and inflammation states of AS.

Methods

The transcriptome profiles of GSE25101 and GSE73754 obtained from the Gene Expression Omnibus (GEO) database were merged for subsequent analyses. The differentially expressed genes (DEGs) were identified using the Bioconductor package Limma and threshold values. Functional enrichment and pathway enrichment analyses were performed using the clusterProfiler package and Gene Set Enrichment Analysis (GSEA). Next, protein-protein interaction (PPI) network of the identified DEGs was constructed by the online database, the Search Tool for the Retrieval of Interacting Genes (STRING), visualization and analysis were performed through Cytoscape software. Subsequently, we applied CIBERSORT algorithm to identify subpopulation proportions of immune cells in peripheral blood samples. Finally, we validated the hub genes with the GSE18781 dataset. Samples were collected from patients to validate gene and protein expression using qRT-PCR and ELISA.

Results

A total of 334 DEGs were identified, including 182 upregulated and 152 downregulated DEGs, between AS patients and normal human controls, which were primarily involved in immune response, autophagy, and natural killer cell-mediated cytotoxicity. The most prominent module and candidate biomarkers were identified from the PPI network. Biomarkers were selected for validation and their expressions were significantly decreased in peripheral blood samples which was consistent with transcriptome sequencing results. Nine genes with AUC > 0.70 were considered to be AS hub genes for ROC curve analysis, including GZMA, GZMK, PRF1, GNLY, NKG7, KLRB1, KLRD1, IL2RB and CD247. Furthermore, CIBERSORT results suggest that AS contained a higher proportion of CD8+ T cells, naive CD4+ T cells, neutrophils, and lower levels of gamma delta T cells compared with the normal controls.

Conclusion

In this study, we identified DEGs combined with their closely related biological functions and propose that granule-associated proteins and immune infiltration maybe involved in the progression of ankylosing spondylitis. These validated hub genes may provide new perspectives for understanding the molecular mechanisms of ankylosing spondylitis.

CD8+ tissue-resident memory T cells promote liver fibrosis resolution by inducing apoptosis of hepatic stellate cells

Non-alcoholic steatohepatitis (NASH) is a leading cause of chronic liver disease that can progress to liver fibrosis. Recent clinical advance suggests a reversibility of liver fibrosis, but the cellular and molecular mechanisms underlying NASH resolution remain unclarified. Here, using a murine diet-induced NASH and the subsequent resolution model, we demonstrate direct roles of CD8⁺ tissue-resident memory CD8⁺ T (CD8⁺ Trm) cells in resolving liver fibrosis. Single-cell transcriptome analysis and FACS analysis revealed CD69⁺CD103⁻CD8⁺ Trm cell enrichment in NASH resolution livers. The reduction of liver CD8⁺ Trm cells, maintained by tissue IL-15, significantly delayed fibrosis resolution, while adoptive transfer of these cells protected mice from fibrosis progression. During resolution, CD8⁺ Trm cells attracted hepatic stellate cells (HSCs) in a CCR5-dependent manner, and predisposed activated HSCs to FasL-Fas-mediated apoptosis. Histological assessment of patients with NASH revealed CD69⁺CD8⁺ Trm abundance in fibrotic areas, further supporting their roles in humans. These results highlight the undefined role of liver CD8⁺ Trm in fibrosis resolution.

The cellular and molecular mechanisms underlying the resolution of non-alcoholic steatohepatitis remain incompletely understood. Here the authors report a single cell-based analysis that identified CD8 + tissue-resident memory T cells, which contribute to resolution of liver fibrosis potentially via elimination of hepatic stellate cells through Fas-mediated cytotoxicity.

Intracellular and Extracellular Roles of Granzyme K

Granzymes are a family of serine proteases stored in granules inside cytotoxic cells of the immune system. Granzyme K (GrK) has been only limitedly characterized and knowledge on its molecular functions is emerging. Traditionally GrK is described as a granule-secreted, pro-apoptotic serine protease. However, accumulating evidence is redefining the functions of GrK by the discovery of novel intracellular (e.g. cytotoxicity, inhibition of viral replication) and extracellular roles (e.g. endothelial activation and modulation of a pro-inflammatory immune cytokine response). Moreover, elevated GrK levels are associated with disease, including viral and bacterial infections, airway inflammation and thermal injury. This review aims to summarize and discuss the current knowledge of i) intracellular and extracellular GrK activity, ii) cytotoxic and non-cytotoxic GrK functioning, iii) the role of GrK in disease, and iv) GrK as a potential therapeutic target.

Three hematologic/immune system-specific expressed genes are considered as the potential biomarkers for the diagnosis of early rheumatoid arthritis through bioinformatics analysis

BACKGROUND

Rheumatoid arthritis (RA) is the most common chronic autoimmune connective tissue disease. However, early RA is difficult to diagnose due to the lack of effective biomarkers. This study aimed to identify new biomarkers and mechanisms for RA disease progression at the transcriptome level through a combination of microarray and bioinformatics analyses.

METHODS

Microarray datasets for synovial tissue in RA or osteoarthritis (OA) were downloaded from the Gene Expression Omnibus (GEO) database, and differentially expressed genes (DEGs) were identified by R software. Tissue/organ-specific genes were recognized by BioGPS. Enrichment analyses were performed and protein-protein interaction (PPI) networks were constructed to understand the functions and enriched pathways of DEGs and to identify hub genes. Cytoscape was used to construct the co-expressed network and competitive endogenous RNA (ceRNA) networks. Biomarkers with high diagnostic value for the early diagnosis of RA were validated by GEO datasets. The ggpubr package was used to perform statistical analyses with Student's t-test.

RESULTS

A total of 275 DEGs were identified between 16 RA samples and 10 OA samples from the datasets GSE77298 and GSE82107. Among these DEGs, 71 tissue/organ-specific expressed genes were recognized. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis indicated that DEGs are mostly enriched in immune response, immune-related biological process, immune system, and cytokine signal pathways. Fifteen hub genes and gene cluster modules were identified by Cytoscape. Eight haematologic/immune system-specific expressed hub genes were verified by GEO datasets. GZMA, PRC1, and TTK may be potential biomarkers for diagnosis of early RA. NEAT1-miR-212-3p/miR-132-3p/miR-129-5p-TTK, XIST-miR-25-3p/miR-129-5p-GZMA, and TTK_hsa_circ_0077158- miR-212-3p/miR-132-3p/miR-129-5p-TTK might be potential RNA regulatory pathways to regulate the disease progression of early RA.

CONCLUSIONS

This work identified three haematologic/immune system-specific expressed genes, namely, GZMA, PRC1, and TTK, as potential biomarkers for the early diagnosis and treatment of RA and provided insight into the mechanisms of disease development in RA at the transcriptome level. In addition, we proposed that NEAT1-miR-212-3p/miR-132-3p/miR-129-5p-TTK, XIST-miR-25-3p/miR-129-5p-GZMA, and TTK_hsa_circ_0077158-miR-212-3p/miR-132-3p/miR-129-5p-TTK are potential RNA regulatory pathways that control disease progression in early RA.

Obesity induced by high-fat diet is associated with critical changes in biological and molecular functions of mesenchymal stromal cells present in visceral adipose tissue

The mesenchymal stromal cells (MSCs) residing within the stromal component of visceral adipose tissue appear to be greatly affected by obesity, with impairment of their functions and presence of senescence. To gain further insight into these phenomena, we analyzed the changes in total proteome content and secretome of mouse MSCs after a high-fat diet (HFD) treatment compared to a normal diet (ND). In healthy conditions, MSCs are endowed with functions mainly devoted to vesicle trafficking. These cells have an immunoregulatory role, affecting leukocyte activation and migration, acute inflammation phase response, chemokine signaling, and platelet activities. They also present a robust response to stress. We identified four signaling pathways (TGF-β, VEGFR2, HMGB1, and Leptin) that appear to govern the cells' functions. In the obese mice, MSCs showed a change in their functions. The immunoregulation shifted toward pro-inflammatory tasks with the activation of interleukin-1 pathway and of Granzyme A signaling. Moreover, the methionine degradation pathway and the processing of capped intronless pre-mRNAs may be related to the inflammation process. The signaling pathways we identified in ND MSCs were replaced by MET, WNT, and FGFR2 signal transduction, which may play a role in promoting inflammation, cancer, and aging.

Endothelial Protease Activated Receptor 1 (PAR1) Signalling Is Required for Lymphocyte Transmigration across Brain Microvascular Endothelial Cells

Lymphocyte transendothelial migration (TEM) relies on ICAM-1 engagement on the luminal surface of the endothelial cells (ECs). In blood–brain barrier (BBB) ECs, ICAM-1 triggers TEM signalling, including through JNK MAP kinase and AMP-activated protein kinase (AMPK), which lead to the phosphorylation and internalisation of the adherens junction protein VE-cadherin. In addition to ICAM-1, G protein-coupled receptors (GPCRs) are also required for lymphocytes TEM across BBB ECs. Here, we investigated the role of protease activated GPCRs (PARs) and found a specific role for PAR1 in support of lymphocyte TEM across BBB ECs in vitro. PAR1 requirement for TEM was confirmed using protease inhibitors, specific small molecule and peptide antagonists, function blocking antibodies and siRNA-mediated knockdown. In BBB ECs, PAR1 stimulation led to activation of signalling pathways essential to TEM; notably involving JNK and endothelial nitric oxide synthase (eNOS), with the latter downstream of AMPK. In turn, nitric oxide production through eNOS was essential for TEM by modulating VE-cadherin on Y731. Collectively, our data showed that non-canonical PAR1 activation by a lymphocyte-released serine protease is required for lymphocyte TEM across the BBB in vitro, and that this feeds into previously established ICAM-1-mediated endothelial TEM signalling pathways.