TSG-6: a multifunctional protein associated with inflammation

A diagnostic signatures for intervertebral disc degeneration using TNFAIP6 and COL6A2 based on single-cell RNA-seq and bulk RNA-seq analyses

OBJECTIVES

Intervertebral disc degeneration (IVDD) is a prevalent degenerative condition associated with a high incidence rate of low back pain and disability. This study aimed to identify potential biomarkers and signaling pathways associated with IVDD.

METHODS

Biomarkers were discerned through bulk-RNA and single-cell RNA sequencing (scRNA-Seq) investigations of IVDD cases from the Gene Expression Omnibus (GEO) database. Following this, two central genes were identified. Furthermore, gene set enrichment analysis (GSEA) and receiver operating characteristic (ROC) curve analysis were conducted. The transcriptional factor (TF) derived from nucleus pulposus (NP) cells was examined through the DoRothEA R package. RT-qPCR and IHC techniques were employed to confirm the expression of the two hub genes and their associated genes in tissue samples.

RESULTS

The proteins Tumor necrosis factor-inducible gene 6 protein (TNFAIP6) and collagen VI-α2 (COL6A2) were frequently analyzed using a combination of DEGs from datasets GSE70362, GSE124272, and scRNA-seq. Examination of gene expression across multiple datasets indicated significant differences in TNFAIP6 and COL6A2 levels in IVDD compared to control or normal groups (p < 0.05). These two central genes demonstrated strong diagnostic utility in the training cohort and reliable predictive value in the validation datasets. Our study verified the potential role of ZEB2 as a TF in regulating two key genes associated with IVDD. Furthermore, qPCR and IHC confirmed elevated expression levels of the hub genes and transcription factor.

CONCLUSION

We identified biomarkers, specifically TNFAIP6 and COL6A2, that have the potential to predict disease activity and aid in the diagnosis of IVDD.

Conditional Tnfaip6-Knockout in Inner Ear Hair Cells Does not Alter Auditory Function

Noise-induced hearing loss is a worldwide public health issue that is characterized by temporary or permanent changes in hearing sensitivity. This condition is closely linked to inflammatory responses, and interventions targeting the inflammatory gene tumor necrosis factor-alpha (TNFα) are known to mitigate cochlear noise damage. TNFα-induced proteins (TNFAIPs) are a family of translucent acidic proteins, and TNFAIP6 has a notable association with inflammatory responses. To date, there have been few reports on TNFAIP6 levels in the inner ear. To elucidate the precise mechanism, we generated transgenic mouse models with conditional knockout of Tnfaip6 (Tnfaip6 cKO). Evaluation of hair cell morphology and function revealed no significant differences in hair cell numbers or ribbon synapses between Tnfaip6 cKO and wild-type mice. Moreover, there were no notable variations in hair cell numbers or hearing function in noisy environments. Our results indicate that Tnfaip6 does not have a substantial impact on the auditory system.

Effects of Release of TSG-6 from Heparin Hydrogels on Supraspinatus Muscle Regeneration

Muscle degeneration after rotator cuff tendon tear is a significant clinical problem. In these experiments, we developed a poly(ethylene glycol)-based injectable granular hydrogel containing two heparin derivatives (fully sulfated [Hep] and fully desulfated [Hep-]) as well as a matrix metalloproteinase-sensitive peptide to promote sustained release of tumor necrosis factor-stimulated gene 6 (TSG-6) over 14+ days in vivo in a rat model of rotator cuff muscle injury. The hydrogel formulations demonstrated similar release profiles in vivo, thus facilitating comparisons between delivery from heparin derivatives on the level of tissue repair in two different areas of muscle (near the myotendious junction [MTJ] and in the muscle belly [MB]) that have been shown previously to have differing responses to rotator cuff tendon injury. We hypothesized that sustained delivery of TSG-6 would enhance the anti-inflammatory response following rotator cuff injury through macrophage polarization and that release from Hep would potentiate this effect throughout the muscle. Inflammatory/immune cells, satellite cells, and fibroadipogenic progenitor cells were analyzed by flow cytometry 3 and 7 days after injury and hydrogel injection, while metrics of muscle healing were examined via immunohistochemistry up to day 14. Results showed controlled delivery of TSG-6 from Hep caused heightened macrophage response (day 7 macrophages, 4.00 ± 1.85% single cells, M2a, 3.27 ± 1.95% single cells) and increased markers of early muscle regeneration (embryonic heavy chain staining) by day 7, particularly in the MTJ region of the muscle. This work provides a novel strategy for localized, controlled delivery of TSG-6 to enhance muscle healing after rotator cuff tear.

CRISPR-dCas9 Activation of TSG-6 in MSCs Modulates the Cargo of MSC-Derived Extracellular Vesicles and Attenuates Inflammatory Responses in Human Intervertebral Disc Cells In Vitro

Purpose

The purpose of this study was to boost the therapeutic effect of mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) by overexpressing the gene TSG-6 through CRISPR activation, and assess the biological activity of EVs from these modified MSCs in vitro on human intervertebral disc (IVD) cells.

Methods

An immortalized human MSC line was transduced with a CRISPR activation lentivirus system targeting TSG-6. MSC-EVs were harvested by ultracentrifugation and particle number/size distribution was determined by nanoparticle tracking analysis. The efficiency of transduction activation was assessed by analyzing gene and protein expression. EV proteomic contents were analyzed by mass spectrometry. Human IVD cells from patients undergoing spinal surgery were isolated, expanded, exposed to IL-1β pre-stimulation and co-treated with MSC-EVs.

Results

MSC-EVs presented size distribution, morphology, and molecular markers consistent with common EV characteristics. The expression level of TSG-6 was significantly higher (> 800 fold) in transduced MSCs relative to controls. Protein analysis of MSCs and EVs showed higher protein expression of TSG-6 in CRISPR activated samples than controls. Proteomics of EVs identified 35 proteins (including TSG-6) that were differentially expressed in TSG-6 activated EVs vs control EVs. EV co-Treatment of IL-1β pre-Stimulated IVD cells resulted in a significant downregulation of IL-8 and COX-2.

Conclusions

We successfully generated an MSC line overexpressing TSG-6. Furthermore, we show that EVs isolated from these modified MSCs have the potential to attenuate the pro-inflammatory gene expression in IVD cells. This genomic engineering approach hence holds promise for boosting the therapeutic effects of EVs.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12195-025-00843-4.

Tumor necrosis factor-stimulated gene-6 inhibits endoplasmic reticulum stress in the ischemic mouse kidney

Kidney tissue injury in renal artery stenosis (RAS) involves inflammation, endoplasmic reticulum stress (ERS), and mitochondria damage. Tumor necrosis factor-stimulated gene-6 (TSG-6), an endogenous reparative molecule, may decrease ERS and improve renal function. To assess its impact on the stenotic murine kidney, we injected TSG-6 or vehicle for two weeks in mice with RAS. At completion, we assessed stenotic kidney function and oxygenation, inflammation, and expression of ERS-related genes. TSG-6 treatment reduced renal hypoxia, urinary protein and plasma creatinine levels, renal fibrosis, and apoptosis. TSG-6 also exhibited an anti-inflammatory effect, reflected in the downregulated expression of the Toll-like receptor 4 (TLR4)/nuclear factor κB (NF-κB) pathway in murine kidneys in vivo and HK-2 cells in vitro. Moreover, ERS-related molecules were downregulated after TSG-6 treatment, while most indicators of mitochondrial unfolded protein response remained unaltered. Therefore, TSG-6 alleviates inflammation, ERS, apoptosis, and fibrosis in the post-stenotic mouse kidney. These observations position TSG-6 as a potential therapeutic tool in RAS.

Injury From Nematode Lung Migration Induces an IL-13-Dependent Hyaluronan Matrix

A consistent feature of lung injury is a rapid and sustained accumulation of hyaluronan (HA). The rodent gut-dwelling nematode Nippostrongylus brasiliensis (Nb) induces tissue damage as it migrates through the lungs. Type 2 immune responses are essential for the repair of the lungs, hence Nb infection is a well-established model to study immune-mediated lung repair. We found that Nb infection was associated with increased HA in the lung, which peaked at d7 post-infection (p.i.). Deposition of HA in the alveolar epithelium correlated with regions of damaged tissue and the type 2 immune response, which is characterized by eosinophilia and increased type 2 cytokines such as IL-13. Consistent with the accumulation of HA, we observed increased expression of the major synthase Has2, alongside decreased expression of Hyal1, Hyal2, and Tmem2, which can degrade existing HA. Expression of Tsg6 was also increased and correlated with the presence of inter-α-inhibitor heavy chain-HA complexes (HC·HA) at d7 p.i. Using IL-13-deficient mice, we found that the accumulation of HA during Nb infection was IL-13 dependent. Our data thus provide further evidence that IL-13 is a modulator of the HA matrix during lung challenge and links IL-13-mediated HA regulation to tissue repair pathways.

Brain Ischemic Tolerance Triggered by Preconditioning Involves Modulation of Tumor Necrosis Factor-α-Stimulated Gene 6 (TSG-6) in Mice Subjected to Transient Middle Cerebral Artery Occlusion

Ischemic preconditioning (PC) induced by a sub-lethal cerebral insult triggers brain tolerance against a subsequent severe injury through diverse mechanisms, including the modulation of the immune system. Tumor necrosis factor (TNF)-α-stimulated gene 6 (TSG-6), a hyaluronate (HA)-binding protein, has recently been involved in the regulation of the neuroimmune response following ischemic stroke. Thus, we aimed at assessing whether the neuroprotective effects of ischemic PC involve the modulation of TSG-6 in a murine model of transient middle cerebral artery occlusion (MCAo). The expression of TSG-6 was significantly elevated in the ischemic cortex of mice subjected to 1 h MCAo followed by 24 h reperfusion, while this effect was further potentiated (p < 0.05 vs. MCAo) by pre-exposure to ischemic PC (i.e., 15 min MCAo) 72 h before. By immunofluorescence analysis, we detected TSG-6 expression mainly in astrocytes and myeloid cells populating the lesioned cerebral cortex, with a more intense signal in tissue from mice pre-exposed to ischemic PC. By contrast, levels of TSG-6 were reduced after 24 h of reperfusion in plasma (p < 0.05 vs. SHAM), but were dramatically elevated when severe ischemia (1 h MCAo) was preceded by ischemic PC (p < 0.001 vs. MCAo) that also resulted in significant neuroprotection. In conclusion, our data demonstrate that neuroprotection exerted by ischemic PC is associated with the elevation of TSG-6 protein levels both in the brain and in plasma, further underscoring the beneficial effects of this endogenous modulator of the immune system.

Inter- and Intra-donor variability in bone marrow-derived mesenchymal stromal cells: implications for clinical applications

BACKGROUND AIMS

Mesenchymal stromal cells (MSCs) are attractive as a therapeutic modality in multiple disease conditions characterized by inflammation and vascular compromise. Logistically they are advantageous because they can be isolated from adult tissue sources, such as bone marrow (BM). The phase 2a START clinical trial determined BM-MSCs to be safe in patients with moderate-to-severe acute respiratory distress syndrome (ARDS). Herein, we examine a subset of the clinical doses of MSCs generated for the phase 2a START trial from three unique donors (1-3), where one of the donors' donated BM on two separate occasions (donor 3 and 3W).

METHODS

The main objective of this study was to correlate properties of the cells from the four lots with plasma biomarkers from treated patients and relevant to ARDS outcomes. To do this we evaluated MSC donor lots for (i) post-thaw viability, (ii) growth kinetics, (iii) metabolism, (iv) surface marker expression, (v) protein expression, (vi) immunomodulatory ability and (vii) their functional effects on regulating endothelial cell permeability.

RESULTS

MSC-specific marker expression and protection of thrombin-challenged endothelial barrier permeability was similar among all four donor lots. Inter and intra-donor variability was observed in all the other in vitro assays. Furthermore, patient plasma ANG-2 and protein C levels at 6 hours post-transfusion were correlated to cell viability in an inter- and intra-donor dependent manner.

CONCLUSIONS

These findings highlight the potential of donor dependent (inter-) and collection dependent (intra-) effects in patient biomarker expression.

Chemical modification of hyaluronan oligosaccharides differentially modulates hyaluronan-hyaladherin interactions

The glycosaminoglycan hyaluronan (HA) is a ubiquitous, nonsulfated polysaccharide with diverse biological roles mediated through its interactions with HA-binding proteins (HABPs). Most HABPs belong to the Link module superfamily, including the major HA receptor, CD44, and secreted protein TSG-6, which catalyzes the covalent transfer of heavy chains from inter-α-inhibitor onto HA. The structures of the HA-binding domains (HABDs) of CD44 (HABD_CD44) and TSG-6 (Link_TSG6) have been determined and their interactions with HA extensively characterized. The mechanisms of binding are different, with Link_TSG6 interacting with HA primarily via ionic and CH-π interactions, whereas HABD_CD44 binds solely via hydrogen bonds and van der Waals forces. Here, we exploit these differences to generate HA oligosaccharides, chemically modified at their reducing ends, that bind specifically and differentially to these target HABPs. Hexasaccharides (HA6AN) modified with 2- or 3-aminobenzoic acid (HA6-2AA, HA6-3AA) or 2-amino-4-methoxybenzoic acid (HA6-2A4MBA), had increased affinities for Link_TSG6 compared to unmodified HA6AN. These modifications did not increase the affinity for CD44_HABD. A model of HA6-2AA (derived from the solution dynamic 3D structure of HA4-2AA) was docked into the Link_TSG6 structure, providing evidence that the 2AA-carboxyl forms a salt bridge with Arginine-81. These modeling results informed a second series of chemical modifications for HA oligosaccharides, which again showed differential binding to the two proteins. Several modifications to HA4 and HA6 were found to convert the oligosaccharide into substrates for heavy chain transfer, whereas unmodified HA4 and HA6 are not. This study has generated valuable research tools to further understand HA biology.

Effects of Release of TSG-6 from Heparin Hydrogels on Supraspinatus Muscle Regeneration

Muscle degeneration after rotator cuff tendon tear is a significant clinical problem. In these experiments, we developed a poly(ethylene glycol)-based injectable granular hydrogel containing two heparin derivatives (fully sulfated (Hep) and fully desulfated (Hep-)) as well as a matrix metalloproteinase-sensitive peptide to promote sustained release of Tumor Necrosis Factor Stimulated Gene 6 (TSG-6) over 14+ days in vivo in a rat model of rotator cuff muscle injury. The hydrogel formulations demonstrated similar release profiles in vivo , thus facilitating comparisons between delivery from heparin derivatives on level of tissue repair in two different areas of muscle (near the myotendious junction (MTJ) and in the muscle belly (MB)) that have been shown previously to have differing responses to rotator cuff tendon injury. We hypothesized that sustained delivery of TSG-6 would enhance the anti-inflammatory response following rotator cuff injury through macrophage polarization, and that release from a fully sulfated heparin derivative (Hep) would potentiate this effect throughout the muscle. Inflammatory/immune cells, satellite cells, and fibroadipogenic progenitor cells, were analyzed by flow cytometery 3 and 7 days after injury and hydrogel injection, while metrics of muscle healing were examined via immunohistochemistry up to Day 14. Results showed controlled delivery of TSG-6 from Hep caused heightened macrophage response (Day 14 macrophages, 4.00 ± 1.85% single cells, M2a, 3.27 ± 1.95% single cells) and increased markers of early muscle regeneration (embryonic heavy chain staining) by Day 7, particularly in the MTJ region of the muscle, compared to release from desulfated heparin hydrogels. This work provides a novel strategy for localized, controlled delivery of TSG-6 to enhance muscle healing after rotator cuff tear.

IMPACT STATEMENT

Rotator cuff tear is a significant problem that can cause muscle degeneration. In this study, a hydrogel particle system was developed for sustained release of an anti-inflammatory protein, Tumor Necrosis Factor Stimulated Gene 6 (TSG-6), to injured muscle. Release of the protein from a fully sulfated heparin hydrogel-based carrier demonstrated greater changes in amount inflammatory cells and more early regenerative effects than a less-sulfated carrier. Thus, this work provides a novel strategy for localized, controlled delivery of an anti-inflammatory protein to enhance muscle healing after rotator cuff tear.

Epigenomics and the Brain-gut Axis: Impact of Adverse Childhood Experiences and Therapeutic Challenges

The brain-gut axis represents a bidirectional communication network that integrates neural, hormonal, and immunological signaling between the central nervous system and the gastrointestinal tract. Adverse childhood experiences (ACEs) have increasingly been recognized for their profound impact on this axis, with implications for both mental and physical health outcomes. This mini-review explores the emerging field of epigenomics-specifically, how epigenetic modifications incurred by ACEs can influence the brain-gut axis and contribute to the pathophysiology of various disorders. We examine the evidence linking epigenetic mechanisms such as DNA methylation, histone modifications, and non-coding RNAs to the modulation of gene expression involved in stress responses, neurodevelopment, and immune function-all of which intersect at the brain-gut axis. Additionally, we discuss the emerging potential of the gut microbiome as both a target and mediator of epigenetic changes, further influencing brain-gut communication in the context of ACEs. The methodological and therapeutic challenges posed by these insights are significant. The reversibility of epigenetic marks and the long-term consequences of early life stress require innovative and comprehensive approaches to intervention. This underscores the need for comprehensive strategies encompassing psychosocial, pharmacological, neuromodulation, and lifestyle interventions tailored to address ACEs' individualized and persistent effects. Future directions call for a multi-disciplinary approach and longitudinal studies to uncover the full extent of ACEs' impact on epigenetic regulation and the brain-gut axis, with the goal of developing targeted therapies to mitigate the long-lasting effects on health.

TFAIP6 facilitates hepatocellular carcinoma cell glycolysis through upregulating c-myc/PKM2 axis

Background

Hepatocellular carcinoma (HCC) is the most prevalent liver cancer. Despite of the improvement of therapies, the durable response rate and survival benefit are still limited for HCC patients. It's urgent to clarify the molecular mechanisms and find therapeutic strategies to improve the clinical outcome. TNFα-stimulated gene-6 (TNFAIP6) plays a critical role in the prognosis of various tumors, but its roles in HCC are still unclear.

Methods

Quantitative real-time PCR (qRT-PCR) and immunohistochemistry (IHC) analysis were employed to evaluate the clinical relevance of TNFAIP6 expressions in HCC patients. Cell counting kit-8 (CCK-8), Edu assay, and transwell assay were performed to evaluate the malignancy of HCC cells. Glucose uptake, lactate production, ATP production, extracellular acidification rate (ECAR) by Seahorse XF analyzer were employed to evaluate the role of TNFAIP6 in the regulation of aerobic glycolysis. The expressions of key proteins involved in glycolysis were examined by Western blot. Co-immunoprecipitation (Co-IP) and chromatin immunoprecipitation (ChIP) were used for protein-protein interactions or protein-RNA interactions respectively. Knockdown and overexpression of TNFAIP6 in HCC cells were employed for analyzing the functions of TNFAIP6 in HCC.

Results

TNFAIP6 was significantly upregulated in HCC and predicted a poor clinical prognosis. Knockdown of TNFAIP6 inhibited in vitro cell proliferation, invasion, migration, as well as glycolysis in HCC cells. Mechanistically, we clarified that TNFAIP6 interacted with heterogeneous nuclear ribonucleoprotein C (HNRNPC), stabilized c-Myc mRNA and upregulated pyruvate kinase M2 (PKM2) to promote glycolysis.

Conclusions

Our study reveals a molecular mechanism by which TNFAIP6 promotes aerobic glycolysis, which is beneficial for malignance of HCC and provides a potential clinical therapy for disease management.

Tumor necrosis factor-inducible gene 6 protein and its derived peptide ameliorate liver fibrosis by repressing CD44 activation in mice with alcohol-related liver disease

BACKGROUND

Alcohol-related liver disease (ALD) is a major health concern worldwide, but effective therapeutics for ALD are still lacking. Tumor necrosis factor-inducible gene 6 protein (TSG-6), a cytokine released from mesenchymal stem cells, was shown to reduce liver fibrosis and promote successful liver repair in mice with chronically damaged livers. However, the effect of TSG-6 and the mechanism underlying its activity in ALD remain poorly understood.

METHODS

To investigate its function in ALD mice with fibrosis, male mice chronically fed an ethanol (EtOH)-containing diet for 9 weeks were treated with TSG-6 (EtOH + TSG-6) or PBS (EtOH + Veh) for an additional 3 weeks.

RESULTS

Severe hepatic injury in EtOH-treated mice was markedly decreased in TSG-6-treated mice fed EtOH. The EtOH + TSG-6 group had less fibrosis than the EtOH + Veh group. Activation of cluster of differentiation 44 (CD44) was reported to promote HSC activation. CD44 and nuclear CD44 intracellular domain (ICD), a CD44 activator which were upregulated in activated HSCs and ALD mice were significantly downregulated in TSG-6-exposed mice fed EtOH. TSG-6 interacted directly with the catalytic site of MMP14, a proteolytic enzyme that cleaves CD44, inhibited CD44 cleavage to CD44ICD, and reduced HSC activation and liver fibrosis in ALD mice. In addition, a novel peptide designed to include a region that binds to the catalytic site of MMP14 suppressed CD44 activation and attenuated alcohol-induced liver injury, including fibrosis, in mice.

CONCLUSIONS

These results demonstrate that TSG-6 attenuates alcohol-induced liver damage and fibrosis by blocking CD44 cleavage to CD44ICD and suggest that TSG-6 and TSG-6-mimicking peptide could be used as therapeutics for ALD with fibrosis.

TSG-6-Mediated Extracellular Matrix Modifications Regulate Hypoxic-Ischemic Brain Injury

Proteoglycans containing link domains modify the extracellular matrix (ECM) to regulate cellular homeostasis and can also sensitize tissues/organs to injury and stress. Hypoxic-ischemic (H-I) injury disrupts cellular homeostasis by activating inflammation and attenuating regeneration and repair pathways. In the brain, the main component of the ECM is the glycosaminoglycan hyaluronic acid (HA), but whether HA modifications of the ECM regulate cellular homeostasis and response to H-I injury is not known. In this report, employing both male and female mice, we demonstrate that link-domain-containing proteoglycan, TNFα-stimulated gene-6 (TSG-6), is active in the brain from birth onward and differentially modifies ECM HA during discrete neurodevelopmental windows. ECM HA modification by TSG-6 enables it to serve as a developmental switch to regulate the activity of the Hippo pathway effector protein, yes-associated protein 1 (YAP1), in the maturing brain and in response to H-I injury. Mice that lack TSG-6 expression display dysregulated expression of YAP1 targets, excitatory amino acid transporter 1 (EAAT1; glutamate-aspartate transporter) and 2 (EAAT2; glutamate transporter-1). Dysregulation of YAP1 activation in TSG-6-/- mice coincides with age- and sex-dependent sensitization of the brain to H-I injury such that 1-week-old neonates display an anti-inflammatory response in contrast to an enhanced proinflammatory injury reaction in 3-month-old adult males but not females. Our findings thus support that a key regulator of age- and sex-dependent H-I injury response in the mouse brain is modulation of the Hippo-YAP1 pathway by TSG-6-dependent ECM modifications.

Hyaluronic Acid Interacting Molecules Mediated Crosstalk between Cancer Cells and Microenvironment from Primary Tumour to Distant Metastasis

Hyaluronic acid (HA) is a prominent component of the extracellular matrix, and its interactions with HA-interacting molecules (HAIMs) play a critical role in cancer development and disease progression. This review explores the multifaceted role of HAIMs in the context of cancer, focusing on their influence on disease progression by dissecting relevant cellular and molecular mechanisms in tumour cells and the tumour microenvironment. Cancer progression can be profoundly affected by the interactions between HA and HAIMs. They modulate critical processes such as cell adhesion, migration, invasion, and proliferation. The TME serves as a dynamic platform in which HAIMs contribute to the formation of a unique niche. The resulting changes in HA composition profoundly influence the biophysical properties of the TME. These modifications in the TME, in conjunction with HAIMs, impact angiogenesis, immune cell recruitment, and immune evasion. Therefore, understanding the intricate interplay between HAIMs and HA within the cancer context is essential for developing novel therapeutic strategies. Targeting these interactions offers promising avenues for cancer treatment, as they hold the potential to disrupt critical aspects of disease progression and the TME. Further research in this field is imperative for advancing our knowledge and the treatment of cancer.

Endogenous TSG-6 modulates corneal inflammation following chemical injury

PURPOSE

Tumor necrosis factor (TNF)-stimulated gene-6 (TSG-6) is upregulated in various pathophysiological contexts, where it has a diverse repertoire of immunoregulatory functions. Herein, we investigated the expression and function of TSG-6 during corneal homeostasis and after injury.

METHODS

Human corneas, eyeballs from BALB/c (TSG-6+/+), TSG-6+/- and TSG-6-/- mice, human immortalized corneal epithelial cells and murine corneal epithelial progenitor cells were prepared for immunostaining and real time PCR analysis of endogenous expression of TSG-6. Mice were subjected to unilateral corneal debridement or alkali burn (AB) injuries and wound healing assessed over time using fluorescein stain, in vivo confocal microscopy and histology.

RESULTS

TSG-6 is endogenously expressed in the human and mouse cornea and established corneal epithelial cell lines and is upregulated after injury. A loss of TSG-6 has no structural and functional effect in the cornea during homeostasis. No differences were noted in the rate of corneal epithelial wound closure between BALB/c, TSG-6+/- and TSG-6-/- mice. TSG-6-/- mice presented decreased inflammatory response within the first 24 h of injury and accelerated corneal wound healing following AB when compared to control mice.

CONCLUSION

TSG-6 is endogenously expressed in the cornea and upregulated after injury where it propagates the inflammatory response following chemical injury.

Investigating the impact of inflammatory response-related genes on renal fibrosis diagnosis: a machine learning-based study with experimental validation

Renal fibrosis plays a crucial role in the progression of renal diseases, yet the lack of effective diagnostic markers poses challenges in scientific and clinical practices. In this study, we employed machine learning techniques to identify potential biomarkers for renal fibrosis. Utilizing two datasets from the GEO database, we applied LASSO, SVM-RFE and RF algorithms to screen for differentially expressed genes related to inflammatory responses between the renal fibrosis group and the control group. As a result, we identified four genes (CCL5, IFITM1, RIPK2, and TNFAIP6) as promising diagnostic indicators for renal fibrosis. These genes were further validated through in vivo experiments and immunohistochemistry, demonstrating their utility as reliable markers for assessing renal fibrosis. Additionally, we conducted a comprehensive analysis to explore the relationship between these candidate biomarkers, immunity, and drug sensitivity. Integrating these findings, we developed a nomogram with a high discriminative ability, achieving a concordance index of 0.933, enabling the prediction of disease risk in patients with renal fibrosis. Overall, our study presents a predictive model for renal fibrosis and highlights the significance of four potential biomarkers, facilitating clinical diagnosis and personalized treatment. This finding presents valuable insights for advancing precision medicine approaches in the management of renal fibrosis.

Inter-alpha-trypsin inhibitor (IαI) and hyaluronan modifications enhance the innate immune response to influenza virus in the lung

The inter-alpha-trypsin inhibitor (IαI) complex is composed of the bikunin core protein with a single chondroitin sulfate (CS) attached and one or two heavy chains (HCs) covalently linked to the CS chain. The HCs from IαI can be transferred to hyaluronan (HA) through a TNFα-stimulated gene-6 (TSG-6) dependent process to form an HC•HA matrix. Previous studies reported increased IαI, HA, and HC•HA complexes in mouse bronchoalveolar lavage fluid (BALF) post-influenza infection. However, the expression and incorporation of HCs into the HA matrix of the lungs during the clinical course of influenza A virus (IAV) infection and the biological significance of the HC•HA matrix are poorly understood. The present study aimed to better understand the composition of HC•HA matrices in mice infected with IAV and how these matrices regulate the host pulmonary immune response. In IAV infected mice bikunin, HC1-3, TSG-6, and HAS1-3 all show increased gene expression at various times during a 12-day clinical course. The increased accumulation of IαI and HA was confirmed in the lungs of infected mice using immunohistochemistry and quantitative digital pathology. Western blots confirmed increases in the IαI components in BALF and lung tissue at 6 days post-infection (dpi). Interestingly, HCs and bikunin recovered from BALF and plasma from mice 6 dpi with IAV, displayed differences in the HC composition by Western blot analysis and differences in bikunin's CS chain sulfation patterns by mass spectrometry analysis. This strongly suggests that the IαI components were synthesized in the lungs rather than translocated from the vascular compartment. HA was significantly increased in BALF at 6 dpi, and the HA recovered in BALF and lung tissues were modified with HCs indicating the presence of an HC•HA matrix. In vitro experiments using polyinosinic-polycytidylic acid (poly(I:C)) treated mouse lung fibroblasts (MLF) showed that modification of HA with HCs increased cell-associated HA, and that this increase was due to the retention of HA in the MLF glycocalyx. In vitro studies of leukocyte adhesion showed differential binding of lymphoid (Hut78), monocyte (U937), and neutrophil (dHL60) cell lines to HA and HC•HA matrices. Hut78 cells adhered to immobilized HA in a size and concentration-dependent manner. In contrast, the binding of dHL60 and U937 cells depended on generating a HC•HA matrix by MLF. Our in vivo findings, using multiple bronchoalveolar lavages, correlated with our in vitro findings in that lymphoid cells bound more tightly to the HA-glycocalyx in the lungs of influenza-infected mice than neutrophils and mononuclear phagocytes (MNPs). The neutrophils and MNPs were associated with a HC•HA matrix and were more readily lavaged from the lungs. In conclusion, this work shows increased IαI and HA accumulation and the formation of a HC•HA matrix in mouse lungs post-IAV infection. The formation of HA and HC•HA matrices could potentially create specific microenvironments in the lungs for immune cell recruitment and activation during IAV infection.

Anti-inflammatory protein TSG-6 secreted by BMSCs attenuates silica-induced acute pulmonary inflammation by inhibiting NLRP3 inflammasome signaling in macrophages

Silicosis is a severe occupational lung disease caused by inhalation of silica particles. Unfortunately, there are currently limited treatment options available for silicosis. Recent advances have indicated that bone marrow mesenchymal stem cells (BMSCs) have a therapeutic effect on silicosis, but their efficacy and underlying mechanisms remain largely unknown. In this study, we focused on the early phase of silica-induced lung injury to investigate the therapeutic effect of BMSCs. Our findings demonstrated that BMSCs attenuated silica-induced acute pulmonary inflammation by inhibiting NLRP3 inflammasome pathways in lung macrophages. To further understand the mechanisms involved, we utilized RNA sequencing to analyze the transcriptomes of BMSCs co-cultured with silica-stimulated bone marrow-derived macrophages (BMDMs). The results clued tumor necrosis factor-stimulated gene 6 (TSG-6) might be a potentially key paracrine secretion factor released from BMSCs, which exerts a protective effect. Furthermore, the anti-inflammatory and inflammasome pathway inhibition effects of BMSCs were attenuated when TSG-6 expression was silenced, both in vivo and in vitro. Additionally, treatment with exogenous recombinant mouse TSG-6 (rmTSG-6) demonstrated similar effects to BMSCs in attenuating silica-induced inflammation. Overall, our findings suggested that BMSCs can regulate the activation of inflammasome in macrophages by secreting TSG-6, thereby protecting against silica-induced acute pulmonary inflammation both in vivo and in vitro.

Age-related changes in human bone marrow mesenchymal stromal cells: morphology, gene expression profile, immunomodulatory activity and miRNA expression

Introduction

Mesenchymal stromal cells (MSC) are one of the main cellular components of bone marrow (BM) microenvironment. MSC play a key role in tissue regeneration, but they are also capable of immunomodulating activity. With host aging, MSC undergo age-related changes, which alter these functions, contributing to the set-up of "inflammaging", which is known to be the basis for the development of several diseases of the elderly, including cancer. However, there's few data investigating this facet of MSC, mainly obtained using murine models or replicative senescence. The aim of this research was to identify morphological, molecular and functional alterations of human bone marrow-derived MSC from young (yBM-MSC) and old (oBM-MSC) healthy donors.

Methods

MSC were identified by analysis of cell-surface markers according to the ISCT criteria. To evaluate response to inflammatory status, MSC were incubated for 24h in the presence of IL-1β, IFN-α, IFN-ɣ and TNF-α. Macrophages were obtained by differentiation of THP-1 cells through PMA exposure. For M1 polarization experiments, a 24h incubation with LPS and IFN-ɣ was performed. MSC were plated at the bottom of the co-culture transwell system for all the time of cytokine exposure. Gene expression was evaluated by real-time PCR after RNA extraction from BM-MSC or THP-1 culture. Secreted cytokines levels were quantitated through ELISA assays.

Results

Aging MSC display changes in size, morphology and granularity. Higher levels of β-Gal, reactive oxygen species (ROS), IL-6 and IL-8 and impaired colony-forming and cell cycle progression abilities were found in oBM-MSC. Gene expression profile seems to vary according to subjects' age and particularly in oBM-MSC seem to be characterized by an impaired immunomodulating activity, with a reduced inhibition of macrophage M1 status. The comparative analysis of microRNA (miRNA) expression in yBM-MSC and oBM-MSC revealed a significant difference for miRNA known to be involved in macrophage polarization and particularly miR-193b-3p expression is strongly increased after co-culture of macrophages with yBM-MSC.

Conclusion

There are profound differences in terms of morphology, gene and miRNA expression and immunomodulating properties among yBM-MSC and oBM-MSC, supporting the critical role of aging BM microenvironment on senescence, immune-mediated disorders and cancer pathogenesis.

Human Synovial Mesenchymal Stem Cells Expressed Immunoregulatory Factors IDO and TSG6 in a Context of Arthritis Mediated by Alphaviruses

Infection by arthritogenic alphaviruses (aavs) can lead to reactive arthritis, which is characterized by inflammation and persistence of the virus; however, its mechanisms remain ill-characterized. Intriguingly, it has been shown that viral persistence still takes place in spite of robust innate and adaptive immune responses, characterized notably by the infiltration of macrophages (sources of TNF-alpha) as well as T/NK cells (sources of IFN-gamma) in the infected joint. Aavs are known to target mesenchymal stem cells (MSCs) in the synovium, and we herein tested the hypothesis that the infection of MSCs may promote the expression of immunoregulators to skew the anti-viral cellular immune responses. We compared the regulated expression via human synovial MSCs of pro-inflammatory mediators (e.g., IL-1β, IL6, CCL2, miR-221-3p) to that of immunoregulators (e.g., IDO, TSG6, GAS6, miR146a-5p). We used human synovial tissue-derived MSCs which were infected with O'Nyong-Nyong alphavirus (ONNV, class II aav) alone, or combined with recombinant human TNF-α or IFN-γ, to mimic the clinical settings. We confirmed via qPCR and immunofluorescence that ONNV infected human synovial tissue-derived MSCs. Interestingly, ONNV alone did not regulate the expression of pro-inflammatory mediators. In contrast, IDO, TSG6, and GAS6 mRNA expression were increased in response to ONNV infection alone, but particularly when combined with both recombinant cytokines. ONNV infection equally decreased miR-146a-5p and miR-221-3p in the untreated cells and abrogated the stimulatory activity of the recombinant TNF-α but not the IFN-gamma. Our study argues for a major immunoregulatory phenotype of MSCs infected with ONNV which may favor virus persistence in the inflamed joint.

The Role and Therapeutic Implications of Inflammation in the Pathogenesis of Brain Arteriovenous Malformations

Brain arteriovenous malformations (bAVMs) are focal vascular lesions composed of abnormal vascular channels without an intervening capillary network. As a result, high-pressure arterial blood shunts directly into the venous outflow system. These high-flow, low-resistance shunts are composed of dilated, tortuous, and fragile vessels, which are prone to rupture. BAVMs are a leading cause of hemorrhagic stroke in children and young adults. Current treatments for bAVMs are limited to surgery, embolization, and radiosurgery, although even these options are not viable for ~20% of AVM patients due to excessive risk. Critically, inflammation has been suggested to contribute to lesion progression. Here we summarize the current literature discussing the role of the immune system in bAVM pathogenesis and lesion progression, as well as the potential for targeting inflammation to prevent bAVM rupture and intracranial hemorrhage. We conclude by proposing that a dysfunctional endothelium, which harbors the somatic mutations that have been shown to give rise to sporadic bAVMs, may drive disease development and progression by altering the immune status of the brain.

TSG-6 alleviates cerebral ischemia/reperfusion injury and blood-brain barrier disruption by suppressing ER stress-mediated inflammation

Tumor necrosis factor-stimulated gene-6 (TSG-6) exhibits promising neuroprotective activity, but how it influences cerebral ischemia/reperfusion (CIR) injury remains to be established. Here, the impact of TSG-6 on the CIR-induced disturbance in the blood-brain barrier (BBB) and associated neurological degeneration was assessed, and the related molecular processes were explored. In this study, TSG-6 markedly reduced CIR-mediated increases in neurological deficit scores, decreased infarct volume, and protected against the apoptotic death of neurons in MCAO/R model rats. Similarly, TSG-6 pretreatment protected cultured neurons against OGD/R-associated neuronal death. TSG-6 also restored BBB integrity, suppressing PERK-eIF2α and IRE1α-TRAF2 pathway activation in CIR model systems, thereby inhibiting NF-κB, TNF-α, IL-1β, and IL-6. The further use of specific inhibitors of ER stress, 4-phenyl butyric acid (4-PBA), PERK (GSK2656157), and IRE1α (STF083010) demonstrated the ability of ER stress to drive inflammatory activity in the context of CIR injury i the PERK-eIF2α-NF-κB and IRE1α-TRAF2-NF-κB pathways. Consistently, the activation of ER stress using tunicamycin resulted in reversing the beneficial effects of TSG-6 on CIR-associated BBB disruption and neurological damage in vitro and in vivo. Treatment with TSG-6 can protect against CIR injury via the inhibition of ER stress-related inflammatory activity induced through the PERK-eIF2α-NF-κB and IRE1α-TRAF2-NF-κB pathways.

Monitoring regulatory T cells as a prognostic marker in lung transplantation

Lung transplantation is the major surgical procedure, which restores normal lung functioning and provides years of life for patients suffering from major lung diseases. Lung transplant recipients are at high risk of primary graft dysfunction, and chronic lung allograft dysfunction (CLAD) in the form of bronchiolitis obliterative syndrome (BOS). Regulatory T cell (Treg) suppresses effector cells and clinical studies have demonstrated that Treg levels are altered in transplanted lung during BOS progression as compared to normal lung. Here, we discuss levels of Tregs/FOXP3 gene expression as a crucial prognostic biomarker of lung functions during CLAD progression in clinical lung transplant recipients. The review will also discuss Treg mediated immune tolerance, tissue repair, and therapeutic strategies for achieving in-vivo Treg expansion, which will be a potential therapeutic option to reduce inflammation-mediated graft injuries, taper the toxic side effects of ongoing immunosuppressants, and improve lung transplant survival rates.

TSG6 hyaluronan matrix remodeling dampens the inflammatory response during colitis

In response to tissue injury, changes in the extracellular matrix (ECM) can directly affect the inflammatory response and contribute to disease progression or resolution. During inflammation, the glycosaminoglycan hyaluronan (HA) becomes modified by tumor necrosis factor stimulated gene-6 (TSG6). TSG6 covalently transfers heavy chain (HC) proteins from inter-α-trypsin inhibitor (IαI) to HA in a transesterification reaction and is to date is the only known HC-transferase. By modifying the HA matrix, TSG6 generates HC:HA complexes that are implicated in mediating both protective and pathological responses. Inflammatory bowel disease (IBD) is a lifelong chronic disorder with well-described remodeling of the ECM and increased mononuclear leukocyte influx into the intestinal mucosa. Deposition of HC:HA matrices is an early event in inflamed gut tissue that precedes and promotes leukocyte infiltration. However, the mechanisms by which TSG6 contributes to intestinal inflammation are not well understood. The aim of our study was to understand how the TSG6 and its enzymatic activity contributes to the inflammatory response in colitis. Our findings indicate that inflamed tissues of IBD patients show an elevated level of TSG6 and increased HC deposition and that levels of HA strongly associate with TSG6 levels in patient colon tissue specimens. Additionally, we observed that mice lacking TSG6 are more vulnerable to acute colitis and exhibit an aggravated macrophage-associated mucosal immune response characterized by elevated pro-inflammatory cytokines and chemokines and diminished anti-inflammatory mediators including IL-10. Surprisingly, along with significantly increased levels of inflammation in the absence of TSG6, tissue HA levels in mice were found to be significantly reduced and disorganized, absent of typical "HA-cable" structures. Inhibition of TSG6 HC-transferase activity leads to a loss of cell surface HA and leukocyte adhesion, indicating that the enzymatic functions of TSG6 are a major contributor to stability of the HA ECM during inflammation. Finally, using biochemically generated HC:HA matrices derived by TSG6, we show that HC:HA complexes can attenuate the inflammatory response of activated monocytes. In conclusion, our data suggests that TSG6 exerts a tissue-protective, anti-inflammatory effect via the generation of HC:HA complexes that become dysregulated in IBD.

Molecular insights of anti-diabetic compounds and its hyaluronic acid conjugates against aldose reductase enzyme through molecular modeling and simulations study-a novel treatment option for inflammatory diabetes

CONTEXT

Chronic inflammation is a risk factor for diabetes, but it can also be a complication of diabetes, leading to severe diabetes and causing many other clinical manifestations. Inflammation is a major emerging complication in both type I and type II diabetes, which causes increasing interest in targeting inflammation to improve and control diabetes. Diabetes with insulin resistance and impaired glucose utilization in humans and their underlying mechanism is not fully understood. But a growing understanding of the intricacy of the insulin signaling cascade in diabetic inflammatory cells reveals potential target genes and their proteins responsible for severe insulin resistance. With this baseline concept, the current project explores the binding affinities of the hyaluronic acid anti-diabetic compounds conjugates to such target proteins in diabetic inflammatory cells and their molecular geometries. A range of 48 anti-diabetic compounds was screened against aldose reductase binding pocket 3 protein target through in silico molecular docking, and results revealed that three compounds viz, metformin (CID:4091), phenformin (CID:8249), sitagliptin (CID:4,369,359), possess significant binding affinity out of 48 chosen drugs. Further, these three anti-diabetic compounds were conjugated with hyaluronic acid (HA), and their binding affinity and their molecular geometrics towards aldose reductase enzyme were screened compared with the free form of the drug. The molecular geometries of three shortlisted drugs (metformin, phenformin, sitagliptin) and their HA conjugates were also explored through density functional theory studies, and it proves their good molecular geometry towards pocket 3 of aldose reductase target. Further, MD simulation trajectories affirm that HA conjugates possess good binding affinity and simulation trajectories with protein target aldose reductase than a free form of the drug. Our current study unravels the new mechanism of drug targeting for diabetes through HA conjugation for inflammatory diabetes. HA conjugates act as novel drug candidates for treating inflammatory diabetes; however, it needs further human clinical trials.

METHODS

For ligand structure, PubChem, ACD chem sketch, and online structure file generator platform are utilized for ligand preparation. Target protein aldose reductase obtained from protein database (PDB). For molecular docking analysis, AutoDock Vina (Version 4) was utilized. pKCSM online server used to predict ADMET properties of the above three shortlisted drugs from the docking study. Using mol-inspiration software (version 2011.06), three shortlisted compounds' bioactivity scores were predicted. DFT analysis for three shortlisted anti-diabetic drugs and their hyaluronic acid conjugates were calculated using a functional B3LYP set of Gaussian 09 software. Molecular dynamics simulation calculations for six chosen protein-ligand complexes were done through YASARA dynamics software and AMBER14 force field.

Evaluation of tumour necrosis factor alpha-stimulated gene-6 and fibroblast growth factor-2 levels in patients diagnosed with multi-system inflammatory syndrome in children

Investigations are still ongoing about the pathophysiology of multi-system inflammatory syndrome in children, which can progress with serious morbidity and mortality after COVID-19 infection. In this study, we aimed to investigate whether fibroblast growth factor-2 and tumour necrosis factor alpha-stimulated gene-6 levels play a role in the diagnosis of the disease and on cardiac involvement. Twenty-three patients (11 girls, 12 boys) and 26 healthy controls (10 girls, 16 boys) were included in the study. The mean age of the patient and control group was 8.45 ± 2.43 and 10.73 ± 4.27 years, respectively. There was no difference between the fibroblast growth factor-2 and tumour necrosis factor alpha-stimulated gene-6 levels of the patient and control groups. When the patients with myocardial involvement in the patient group were compared with the patients without myocardial involvement in terms of fibroblast growth factor-2 and tumour necrosis factor alpha-stimulated gene-6 levels, no difference was found between these groups. The correlation of fibroblast growth factor-2 and tumour necrosis factor alpha-stimulated gene-6 levels with other laboratory parameters was investigated in the patient group. Fibroblast growth factor-2 was moderately inversely correlated with white blood cell count (r = -0.541, p = 0.008), absolute neutrophil count (r = -0.502, p = 0.015) and C-reactive protein (r = -0.528, p = 0.010). Fibroblast growth factor-2 was strongly inversely correlated with erythrocyte sedimentation rate (r = -0.694, p =<0.001). Our data show that fibroblast growth factor-2 and tumour necrosis factor alpha stimulated gene-6 do not provide sufficient information about diagnosis and cardiac involvement in multi-system inflammatory syndrome in children.

TSG-6 inhibits hypertrophic scar fibroblast proliferation by regulating IRE1α/TRAF2/NF-κB signalling

TNF-stimulated gene (TSG-6) was reported to suppress hypertrophic scar (HS) formation in a rabbit ear model, and the overexpression of TSG-6 in human HS fibroblasts (HSFs) was found to induce their apoptotic death. The molecular basis for these findings, however, remains to be clarified. HSFs were subjected to TSG-6 treatment. Treatment with TSG-6 significantly suppressed HSF proliferation and induced them to undergo apoptosis. Moreover, TSG-6 exposure led to reductions in collagen I, collagen III, and α-SMA mRNA and protein levels, with a corresponding drop in proliferating cell nuclear antigen (PCNA) expression indicative of impaired proliferative activity. Endoplasmic reticulum (ER) stress was also suppressed in these HSFs as demonstrated by decreases in Bip and p-IRE1α expression, downstream inositol requiring enzyme 1 alpha (IRE1α) -Tumor necrosis factor receptor associated factor 2 (TRAF2) pathway signalling was inhibited and treated cells failed to induce NF-κB, TNF-α, IL-1β, and IL-6 expression. Overall, ER stress was found to trigger inflammatory activity in HSFs via the IRE1α-TRAF2 axis, as confirmed with the specific inhibitor of IRE1α STF083010. Additionally, the effects of TSG-6 on apoptosis, collagen I, collagen III, α-SMA, and PCNA of HSFs were reversed by the IRE1α activator thapsigargin (TG). These data suggest that TSG-6 administration can effectively suppress the proliferation of HSFs in part via the inhibition of IRE1α-mediated ER stress-induced inflammation (IRE1α/TRAF2/NF-κB signalling).

Characterization of the Involvement of Tumour Necrosis Factor (TNF)-α-Stimulated Gene 6 (TSG-6) in Ischemic Brain Injury Caused by Middle Cerebral Artery Occlusion in Mouse

The identification of novel targets to modulate the immune response triggered by cerebral ischemia is crucial to promote the development of effective stroke therapeutics. Since tumour necrosis factor (TNF)-α-stimulated gene 6 (TSG-6), a hyaluronate (HA)-binding protein, is involved in the regulation of immune and stromal cell functions in acute neurodegeneration, we aimed to characterize its involvement in ischemic stroke. Transient middle cerebral artery occlusion (1 h MCAo, followed by 6 to 48 of reperfusion) in mice resulted in a significant elevation in cerebral TSG-6 protein levels, mainly localized in neurons and myeloid cells of the lesioned hemisphere. These myeloid cells were clearly infiltrating from the blood, strongly suggesting that brain ischemia also affects TSG-6 in the periphery. Accordingly, TSG-6 mRNA expression was elevated in peripheral blood mononuclear cells (PBMCs) from patients 48 h after ischemic stroke onset, and TSG-6 protein expression was higher in the plasma of mice subjected to 1 h MCAo followed by 48 h of reperfusion. Surprisingly, plasma TSG-6 levels were reduced in the acute phase (i.e., within 24 h of reperfusion) when compared to sham-operated mice, supporting the hypothesis of a detrimental role of TSG-6 in the early reperfusion stage. Accordingly, systemic acute administration of recombinant mouse TSG-6 increased brain levels of the M2 marker Ym1, providing a significant reduction in the brain infarct volume and general neurological deficits in mice subjected to transient MCAo. These findings suggest a pivotal role of TSG-6 in ischemic stroke pathobiology and underscore the clinical relevance of further investigating the mechanisms underlying its immunoregulatory role.

The role of hyaluronan in renal cell carcinoma

Renal cell carcinoma (RCC) is associated with high mortality rates worldwide and survival among RCC patients has not improved significantly in the past few years. A better understanding of the pathogenesis of RCC can enable the development of more effective therapeutic strategies against RCC. Hyaluronan (HA) is a glycosaminoglycan located in the extracellular matrix (ECM) that has several roles in biology, medicine, and physiological processes, such as tissue homeostasis and angiogenesis. Dysregulated HA and its receptors play important roles in fundamental cellular and molecular biology processes such as cell signaling, immune modulation, tumor progression and angiogenesis. There is emerging evidence that alterations in the production of HA regulate RCC development, thereby acting as important biomarkers as well as specific therapeutic targets. Therefore, targeting HA or combining it with other therapies are promising therapeutic strategies. In this Review, we summarize the available data on the role of abnormal regulation of HA and speculate on its potential as a therapeutic target against RCC.

Tumour necrosis factor stimulated gene 6 intrinsically regulates PD-L1 expressions in breast cancer cells, leading to modulation of tumour microenvironment

Recent studies have shown that tumour cells express tumour necrosis factor-inducible gene 6 (TSG-6) and its protein, which is known to play a key role in regulating excessive immune responses and proliferation and growth of mesenchymal stem cells (MSCs). It has not been confirmed whether the inhibition of TSG-6 for tumour cells can suppress tumour cell growth and regulate the activation of immune cells in the tumour microenvironment (TME). TSG-6-specific small interfering RNA was transfected into canine and human breast cancer cells (CIPp, CIPm and BT-20). TSG-6-down-regulated (siTSG-6) cells showed decreased cell proliferation, migration, and invasion abilities. Decreased mRNA expressions of NF-κB, STAT3 and Sox2, confirming that TSG-6 is an upper factor governing tumour growth and metastasis. Notably, siTSG-6 cells showed significantly decreased expression levels of CD44 and PD-L1. Direct and indirect co-culture of canine peripheral blood mononuclear cells (cPBMCs) and the siTSG-6 cells showed significant activation in M1 type macrophages and cytotoxic T cells. They also showed a tendency to decrease in the expression of CTLA-4 and increase in the expression of PD-1. In conclusion, this study suggests that the down-regulation of TSG-6 in breast cancer cells could not only suppress tumour growth and metastasis, and but also regulate TME. Since modulation of immune checkpoint proteins occurs in both tumour cells and immune cells, inhibiting TSG-6 and its protein within the TME could be novel therapeutic target for anticancer treatment.

Mesenchymal stem cells attenuate the proinflammatory cytokine pattern in a guinea pig model of chronic cigarette smoke exposure

AIMS

Cigarette smoke often induces pulmonary and systemic inflammation. In animal models, mesenchymal stem cells (MSC) tend to ameliorate these effects. We aimed to explore the local and systemic expression of cytokines in guinea pigs chronically exposed to cigarette smoke, and their modifications by MSC.

MAIN METHODS

Concentrations of IL-1β, IL-6, IL-8, IL-12, TNF-α, INF-ɣ, TSG-6, MMP-9, TIMP-1, and/or TIMP-2 in serum and bronchoalveolar lavage (BALF) from animals exposed to tobacco smoke (20 cigarettes/day, 5 days/week for 10 weeks) were determined, and mRNA expression of some of them was measured in lung tissue. Intratracheal instillation of allogeneic bone marrow MSC (5x10⁶ cells in 1 ml) was done at week 2.

KEY FINDINGS

After cigarette smoke, IL-6 and IFN-γ increased in serum and BALF, while IL-1β and IL-12 decreased in serum, and TSG-6 and TIMP-2 increased in BALF. IL-1β had a paradoxical increase in BALF. MSC had an almost null effect in unexposed animals. The intratracheal administration of MSC in guinea pigs exposed to cigarette smoke was associated with a statistically significant decrease of IL-12 and TSG-6 in serum, as well as a decrease of IL-1β and IFN-γ and an increase in TIMP-1 in BALF. Concerning mRNA expression in lung tissue, cigarette smoke did not modify the relative amount of the studied transcripts, but even so, MSC decreased the IL-12 mRNA and increased the TIMP-1 mRNA.

SIGNIFICANCE

A single intratracheal instillation of MSC reduces the pulmonary and systemic proinflammatory pattern induced by chronic exposure to cigarette smoke in guinea pigs.

TRIAL REGISTRATION

Not applicable.

Transcriptomic analyses of joint tissues during osteoarthritis development in a rat model reveal dysregulated mechanotransduction and extracellular matrix pathways

OBJECTIVE

Transcriptomic changes in joint tissues during the development of osteoarthritis (OA) are of interest for the discovery of biomarkers and mechanisms of disease. The objective of this study was to use the rat medial meniscus transection (MMT) model to discover stage and tissue-specific transcriptomic changes.

DESIGN

Sham or MMT surgeries were performed in mature rats. Cartilage, menisci and synovium were scored for histopathological changes at 2, 4 and 6 weeks post-surgery and processed for RNA-sequencing. Differentially expressed genes (DEG) were used to identify pathways and mechanisms. Published transcriptomic datasets from animal models and human OA were used to confirm and extend present findings.

RESULTS

The total number of DEGs was already high at 2 weeks (723 in meniscus), followed by cartilage (259) and synovium (42) and declined to varying degrees in meniscus and synovium but increased in cartilage at 6 weeks. The most upregulated genes included tenascins. The 'response to mechanical stimulus' and extracellular matrix-related pathways were enriched in both cartilage and meniscus. Pathways that were enriched in synovium at 4 weeks indicate processes related to synovial hyperplasia and fibrosis. Synovium also showed upregulation of IL-11 and several MMPs. The mechanical stimulus pathway included upregulation of the mechanoreceptors PIEZO1, PIEZO2 and TRPV4 and nerve growth factor. Analysis of data from prior RNA-sequencing studies of animal models and human OA support these findings.

CONCLUSION

These results indicate several shared pathways that are affected during OA in cartilage and meniscus and support the role of mechanotransduction and other pathways in OA pathogenesis.

Tumor Necrosis Factor (TNF)-α-Stimulated Gene 6 (TSG-6): A Promising Immunomodulatory Target in Acute Neurodegenerative Diseases

Tumor necrosis factor (TNF)-α-stimulated gene 6 (TSG-6), the first soluble chemokine-binding protein to be identified in mammals, inhibits chemotaxis and transendothelial migration of neutrophils and attenuates the inflammatory response of dendritic cells, macrophages, monocytes, and T cells. This immunoregulatory protein is a pivotal mediator of the therapeutic efficacy of mesenchymal stem/stromal cells (MSC) in diverse pathological conditions, including neuroinflammation. However, TSG-6 is also constitutively expressed in some tissues, such as the brain and spinal cord, and is generally upregulated in response to inflammation in monocytes/macrophages, dendritic cells, astrocytes, vascular smooth muscle cells and fibroblasts. Due to its ability to modulate sterile inflammation, TSG-6 exerts protective effects in diverse degenerative and inflammatory diseases, including brain disorders. Emerging evidence provides insights into the potential use of TSG-6 as a peripheral diagnostic and/or prognostic biomarker, especially in the context of ischemic stroke, whereby the pathobiological relevance of this protein has also been demonstrated in patients. Thus, in this review, we will discuss the most recent data on the involvement of TSG-6 in neurodegenerative diseases, particularly focusing on relevant anti-inflammatory and immunomodulatory functions. Furthermore, we will examine evidence suggesting novel therapeutic opportunities that can be afforded by modulating TSG-6-related pathways in neuropathological contexts and, most notably, in stroke.

Expression of GPR-68 in Human Corneal and Conjunctival Epithelium. Possible indicator and mediator of attrition associated inflammation at the ocular surface

INTRODUCTION

Attrition and osmotic stress have been identified as major forces in the pathophysiology of dry eye. Impaired tolerance to mechano-transduction in the presence of insufficient lubrication has been associated with disturbances of ocular surface homeostasis and encouragement of inflammatory reactions, challenging the usual regulatory coping mechanisms. In spite of the probable link between enhanced attrition and secondary inflammation, the key mediators driving the vicious cycle of severe dry eye disease have not yet been identified. The goal of this study was therefore to investigate human corneal and conjunctival epithelium for the presence of the G protein-coupled receptor GPR-68. This protein had most recently been shown to be not only chemically activated but also mechanically, possibly through attrition.

METHODS

De-identified sections of human cornea and conjunctiva were stained for the presence of G protein-coupled receptor 68 with specific antibodies using immunohistochemical methods. Results Specific staining for G-protein-coupled receptor 68 (GPR68) was observed in all samples of the cornea throughout the epithelial layers of the corneal epithelium, most prominently in the area of the wing cells and the basement membrane. Even in the conjunctiva, specific staining for GPR-68 was found.

DISCUSSION

The detection of G protein-coupled receptor GPR-68 in human corneal and conjunctival epithelium raises the question of its function and purpose. The mechanical activation of GPR68 in situations with enhanced friction and attrition could modify various cellular functions and possibly jeopardize normal inflammatory homeostasis at the ocular surface. Accordingly, decreased lubrication in dry eye disease could result in activation of GPR-68. This could lead to secondary inflammation, initially in the epithelium and surrounding stroma. Continuous mechanical stress could result in chronic inflammation, also reaching deeper structures of the cornea, possibly making GPR-68 an important actor in the vicious cycle of dry eye disease.

CONCLUSION

G protein-coupled receptor GPR-68, sensitive to flow and mechanic stimulation, is present in the human corneal epithelium and conjunctiva. Decreased lubrication and increased attrition, accompanied by sensations typical for dry eye, might lead to local inflammation. It is possible that subtle signs of conjunctival, and later corneal, surface damage in the context of these sensations could be a better indicator of the need for and success of therapy than the clinical signs of dry eye disease alone, at least in the early stages of the disease. Inhibition of G protein-coupled receptor GPR-68 could represent a new strategy in the treatment of dry eye disease.

TSG6 Plays a Role in Improving Orbital Inflammatory Infiltration and Extracellular Matrix Accumulation in TAO Model Mice

Introduction

TSG-6 plays a wide anti-inflammatory and therapeutic role in a variety of autoimmune diseases as the key mediator of mesenchymal stem cells (MSCs).

Purpose

We aimed to test whether TSG-6 could exert similar effects as MSCS in TAO via establishing TAO animal model immunized by hTSHR-A subunit plasmid.

Material and Methods

We tested the expression level of TSG-6 on intraconal orbital fat from controls and patients with TAO. We established a stable thyroid-associated ophthalmopathy animal model by immunizing 6-week-old female Balb/c mice with recombination hTSHR-A subunit plasmid. After four immunizations, TSG-6 or dexamethasone was injected through the tail vein. The effects of the drugs on body weight, thyroid function, orbital inflammation, fibrosis and lipogenesis were observed.

Results

The expression of TSG-6 in the orbital tissues of TAO patient is lower than that of normal people. In our animal model, mice showed weight loss, higher TT4 and TSHR antibody levels, and ocular symptoms such as inflammation and proptosis. TSG-6 can reduce ocular fibrosis and lipogenesis by inhibiting the infiltration of CD3+ T lymphocytes and macrophages in the mouse model of thyroid associated ophthalmopathy. Compared with dexamethasone, TSG-6 showed comparable anti-inflammatory effect, moreover, it has given a better performance in inhibiting adipogenesis.

Conclusion

It was demonstrated that TSG-6 has a considerable positive impact on improving eye symptoms of TAO mice, which could be a novel candidate for the early treatment of TAO.

Dysfunctional Extracellular Matrix Remodeling Supports Perianal Fistulizing Crohn's Disease by a Mechanoregulated Activation of the Epithelial-to-Mesenchymal Transition

BACKGROUND AND AIMS

Perianal fistula represents one of the most disabling manifestations of Crohn's disease (CD) due to complete destruction of the affected mucosa, which is replaced by granulation tissue and associated with changes in tissue organization. To date, the molecular mechanisms underlying perianal fistula formation are not well defined. Here, we dissected the tissue changes in the fistula area and addressed whether a dysregulation of extracellular matrix (ECM) homeostasis can support fistula formation.

METHODS

Surgical specimens from perianal fistula tissue and the surrounding region of fistulizing CD were analyzed histologically and by RNA sequencing. Genes significantly modulated were validated by real-time polymerase chain reaction, Western blot, and immunofluorescence assays. The effect of the protein product of TNF-stimulated gene-6 (TSG-6) on cell morphology, phenotype, and ECM organization was investigated with endogenous lentivirus-induced overexpression of TSG-6 in Caco-2 cells and with exogenous addition of recombinant human TSG-6 protein to primary fibroblasts from region surrounding fistula. Proliferative and migratory assays were performed.

RESULTS

A markedly different organization of ECM was found across fistula and surrounding fistula regions with an increased expression of integrins and matrix metalloproteinases and hyaluronan (HA) staining in the fistula, associated with increased newly synthesized collagen fibers and mechanosensitive proteins. Among dysregulated genes associated with ECM, TNFAI6 (gene encoding for TSG-6) was as significantly upregulated in the fistula compared with area surrounding fistula, where it promoted the pathological formation of complexes between heavy chains from inter-alpha-inhibitor and HA responsible for the formation of a crosslinked ECM. There was a positive correlation between TNFAI6 expression and expression of mechanosensitive genes in fistula tissue. The overexpression of TSG-6 in Caco-2 cells promoted migration, epithelial-mesenchymal transition, transcription factor SNAI1, and HA synthase (HAs) levels, while in fibroblasts, isolated from the area surrounding the fistula, it promoted an activated phenotype. Moreover, the enrichment of an HA scaffold with recombinant human TSG-6 protein promoted collagen release and increase of SNAI1, ITGA4, ITGA42B, and PTK2B genes, the latter being involved in the transduction of responses to mechanical stimuli.

CONCLUSIONS

By mediating changes in the ECM organization, TSG-6 triggers the epithelial-mesenchymal transition transcription factor SNAI1 through the activation of mechanosensitive proteins. These data point to regulators of ECM as new potential targets for the treatment of CD perianal fistula.

Mesenchymal stem/stromal cells primed by inflammatory cytokines alleviate psoriasis-like inflammation via the TSG-6-neutrophil axis

Psoriasis is currently an incurable skin disorder mainly driven by a chronic inflammatory response. We found that subcutaneous application of umbilical cord- derived mesenchymal stem/stromal cells (MSCs) primed by IFN-γ and TNF-α, referred to as MSCs-IT, exhibited remarkable therapeutic efficacy on imiquimod (IMQ)-induced psoriasis-like inflammation in mice. Neutrophil infiltration, a hallmark of psoriasis, was significantly reduced after treatment with MSCs-IT. We further demonstrated that the effects of MSCs-IT were mediated by tumor necrosis factor (TNF) stimulating gene-6 (TSG-6), which was greatly upregulated in MSCs upon IFN-γ and TNF-α stimulation. MSCs transduced with TSG-6 siRNA lost their therapeutic efficacy while recombinant TSG-6 applied alone could also reduce neutrophil infiltration and alleviate the psoriatic lesions. Furthermore, we demonstrated that TSG-6 could inhibit neutrophil recruitment by decreasing the expression of CXCL1, which may be related to the reduced level of STAT1 phosphorylation in the keratinocytes. Thus, blocking neutrophil recruitment by MSCs-IT or TSG-6 has potential for therapeutic application in human psoriasis.

Antifibrotic TSG-6 Expression Is Synergistically Increased in Both Cells during Coculture of Mesenchymal Stem Cells and Macrophages via the JAK/STAT Signaling Pathway

The pro-inflammatory cytokines tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-1β upregulate TNF-α-stimulated gene 6 (TSG-6); however, current knowledge about the optimal conditions for TSG-6 expression in mesenchymal stem cells (MSCs) is limited. Here, we investigated whether TSG-6 expression varies depending on the polarization state of macrophages co-cultured with adipose tissue-derived stem cells (ASCs) and analyzed the optimal conditions for TSG-6 expression in ASCs. TSG-6 expression increased in ASCs co-cultured with M0, M1, and M2 macrophages indirectly; among them, M1 macrophages resulted in the highest increase in TSG-6 expression in ASCs. TSG-6 expression in ASCs dramatically increased by combination (but not single) treatment of TNF-α, IL-1β, interferon-gamma (IFN-γ), and lipopolysaccharide (LPS). In addition, phosphorylation of signal transducer and activator of transcription (STAT) 1/3 was observed in response to IFN-γ and LPS treatment but not TNF-α and/or IL-1β. STAT1/3 activation synergistically increased TNF-α/IL-1β-dependent TSG-6 expression, and JAK inhibitors suppressed TSG-6 expression both in ASCs and macrophages. In LX-2 hepatic stellate cells, TSG-6 inhibited TGF-β-induced Smad3 phosphorylation, resulting in decreased α-smooth muscle actin (SMA) expression. Moreover, fibrotic activities of LX-2 cells induced by TGF-β were dramatically decreased after indirect co-culture with ASCs and M1 macrophages. These results suggest that a comprehensive inflammatory microenvironment may play an important role in determining the therapeutic properties of ASCs by increasing TSG-6 expression through STAT1/3 activation.

Noncovalent hyaluronan crosslinking by TSG-6: Modulation by heparin, heparan sulfate, and PRG4

The size, conformation, and organization of the glycosaminoglycan hyaluronan (HA) affect its interactions with soluble and cell surface-bound proteins. HA that is induced to form stable networks has unique biological properties relative to unmodified soluble HA. AlphaLISA assay technology offers a facile and general experimental approach to assay protein-mediated networking of HA in solution. Connections formed between two end-biotinylated 50 kDa HA (bHA) chains can be detected by signal arising from streptavidin-coated donor and acceptor beads being brought into close proximity when the bHA chains are bridged by proteins. We observed that incubation of bHA with the protein TSG-6 (tumor necrosis factor alpha stimulated gene/protein 6, TNFAIP/TSG-6) leads to dimerization or higher order multimerization of HA chains in solution. We compared two different heparin (HP) samples and two heparan sulfate (HS) samples for the ability to disrupt HA crosslinking by TSG-6. Both HP samples had approximately three sulfates per disaccharide, and both were effective in inhibiting HA crosslinking by TSG-6. HS with a relatively high degree of sulfation (1.75 per disaccharide) also inhibited TSG-6 mediated HA networking, while HS with a lower degree of sulfation (0.75 per disaccharide) was less effective. We further identified Proteoglycan 4 (PRG4, lubricin) as a TSG-6 ligand, and found it to inhibit TSG-6-mediated HA crosslinking. The effects of HP, HS, and PRG4 on HA crosslinking by TSG-6 were shown to be due to HP/HS/PRG4 inhibition of HA binding to the Link domain of TSG-6. Using the AlphaLISA platform, we also tested other HA-binding proteins for ability to create HA networks. The G1 domain of versican (VG1) effectively networked bHA in solution but required a higher concentration than TSG-6. Cartilage link protein (HAPLN1) and the HA binding protein segment of aggrecan (HABP, G1-IGD-G2) showed only low and variable magnitude HA networking effects. This study unambiguously demonstrates HA crosslinking in solution by TSG-6 and VG1 proteins, and establishes PRG4, HP and highly sulfated HS as modulators of TSG-6 mediated HA crosslinking.

Headway and the remaining hurdles of mesenchymal stem cells therapy for bronchopulmonary dysplasia

OBJECTIVE

Preterm infants are at a high risk of developing BPD. Although progression in neonatal care has improved, BPD still causes significant morbidity and mortality, which can be attributed to the limited therapeutic choices for BPD. This review discusses the potential of MSC in treating BPD as well as their hurdles and possible solutions.

DATA SOURCES

The search for data was not limited to any sites but was mostly performed on all clinical trials available in ClinicalTrials.gov as well as on PubMed by applying the following keywords: lung injury, preterm, inflammation, neonatal, bronchopulmonary dysplasia and mesenchymal stem cells.

STUDY SELECTIONS

The articles chosen for this review were collectively determined to be relevant and appropriate in discussing MSC not only as a potential treatment strategy for curbing the incidence of BPD but also including insights on problems regarding MSC treatment for BPD.

RESULTS

Clinical trials regarding the use of MSC for BPD had good results but also illustrated insights on problems to be addressed in the future regarding the treatment strategy. Despite that, the clinical trials had mostly favourable reviews.

CONCLUSION

With BPD existing as a constant threat and there being no permanent solutions, the idea of regenerative medicine such as MSC may prove to be a breakthrough strategy when it comes to treating BPD. The success in clinical trials led to the formulation of prospective MSC-derived products such as PNEUMOSTEM®, and there is the possibility of a stem cell medication and permanent treatment for BPD in the near future.

Cell-free therapy based on stem cell-derived exosomes: A promising approach for wound healing

There are several successive and overlapping phases in wound healing as a complex process. By the disruption of each of these phases, chronic non-healing wounds are resultant. Despite the present soothing surgeries, standard wound dressings and topical gels, the wound is often not completely closed. Today, stem cells have attracted a huge deal of attention therapeutically and pharmaceutically considering their unique features. However, they have some restrictions. Moreover, it is hoped to eliminate the limitations of cellular therapies based on their derivatives known as exosomes. Exosomes are extracellular vesicles secreted from cells. They have a diameter of almost 30-150 nm and miRNAs, mRNAs, and proteins that are possibly different from the source cell are included in exosomal contents. Such nanovesicles have a key role in the intercellular communication of pathological and physiological procedures. Exosome-based therapy is a new significant method for wound healing. By exosomes effects, wound management may be improved and a new therapeutic model may be highlighted for cell-free therapies with reduced side effects for the wound repair.

Inflammatory bowel disease biomarkers

Inflammatory bowel disease (IBD) is characterized as chronic inflammation in the gastrointestinal tract, which includes two main subtypes, Crohn's disease and ulcerative colitis. Endoscopy combined with biopsy is the most effective way to establish IBD diagnosis and disease management. Imaging techniques have also been developed to monitor IBD. Although effective, the methods are expensive and invasive, which leads to pain and discomfort. Alternative noninvasive biomarkers are being explored as tools for IBD prognosis and disease management. This review focuses on novel biomarkers that have emerged in recent years. These serological biomarkers and microRNAs could potentially be used for disease management in IBD, thereby decreasing patient discomfort and morbidity.

Defining the versican interactome in lung health and disease

The extracellular matrix (ECM) imparts critical mechanical and biochemical information to cells in the lungs. Proteoglycans are essential constituents of the ECM and play a crucial role in controlling numerous biological processes, including regulating cellular phenotype and function. Versican, a chondroitin sulfate proteoglycan required for embryonic development, is almost absent from mature, healthy lungs and is reexpressed and accumulates in acute and chronic lung disease. Studies using genetically engineered mice show that the versican-enriched matrix can be pro- or anti-inflammatory depending on the cellular source or disease process studied. The mechanisms whereby versican develops a contextual ECM remain largely unknown. The primary goal of this review is to provide an overview of the interaction of versican with its many binding partners, the "versican interactome," and how through these interactions, versican is an integrator of complex extracellular information. Hopefully, the information provided in this review will be used to develop future studies to determine how versican and its binding partners can develop contextual ECMs that control select biological processes. Although this review focuses on versican and the lungs, what is described can be extended to other proteoglycans, tissues, and organs.

Identification of TNFAIP6 as a hub gene associated with the progression of glioblastoma by weighted gene co-expression network analysis

This study aims to discover the genetic modules that distinguish glioblastoma multiforme (GBM) from low‐grade glioma (LGG) and identify hub genes. A co‐expression network is constructed using the expression profiles of 28 GBM and LGG patients from the Gene Expression Omnibus database. The authors performed gene ontology (GO) and Kyoto encyclopaedia of genes and genomes (KEGG) analysis on these genes. The maximal clique centrality method was used to identify hub genes. Online tools were employed to confirm the link between hub gene expression and overall patient survival rate. The top 5000 genes with major variance were classified into 18 co‐expression gene modules. GO analysis indicated that abnormal changes in ‘cell migration’ and ‘collagen metabolic process’ were involved in the development of GBM. KEGG analysis suggested that ‘focal adhesion’ and ‘p53 signalling pathway’ regulate the tumour progression. TNFAIP6 was identified as a hub gene, and the expression of TNFAIP6 was increased with the elevation of pathological grade. Survival analysis indicated that the higher the expression of TNFAIP6, the shorter the survival time of patients. The authors identified TNFAIP6 as the hub gene in the progression of GBM, and its high expression indicates the poor prognosis of the patients.

Recent Advancements in Antifibrotic Therapies for Regression of Liver Fibrosis

Cirrhosis is a severe form of liver fibrosis that results in the irreversible replacement of liver tissue with scar tissue in the liver. Environmental toxicity, infections, metabolic causes, or other genetic factors including autoimmune hepatitis can lead to chronic liver injury and can result in inflammation and fibrosis. This activates myofibroblasts to secrete ECM proteins, resulting in the formation of fibrous scars on the liver. Fibrosis regression is possible through the removal of pathophysiological causes as well as the elimination of activated myofibroblasts, resulting in the reabsorption of the scar tissue. To date, a wide range of antifibrotic therapies has been tried and tested, with varying degrees of success. These therapies include the use of growth factors, cytokines, miRNAs, monoclonal antibodies, stem-cell-based approaches, and other approaches that target the ECM. The positive results of preclinical and clinical studies raise the prospect of a viable alternative to liver transplantation in the near future. The present review provides a synopsis of recent antifibrotic treatment modalities for the treatment of liver cirrhosis, as well as a brief summary of clinical trials that have been conducted to date.

Transcriptomic analysis of cumulus cells shows altered pathways in patients with minimal and mild endometriosis

Endometriosis is a chronic inflammatory disorder that is highly associated with infertility. This association seems to be related to oocyte impairment, mainly in the initial stages of endometriosis (minimal and mild), where no distortions or adhesions are present. Nonetheless, invasive oocyte analyses are not routinely feasible; thus, indirect assessment of oocyte quality is highly desirable, and, in this context, cumulus cells (CCs) may be more suitable targets of analysis. CCs are crucial in oocyte development and could be used as an index of oocyte quality. Therefore, this prospective case–control study aimed to shed light on the infertility mechanisms of endometriosis I/II by analyzing the CCs’ mRNA transcription profile (women with endometriosis I/II, n = 9) compared to controls (women with tubal abnormalities or male factor, n = 9). The transcriptomic analyses of CCs from patients with minimal and mild endometriosis revealed 26 differentially expressed genes compared to the controls. The enrichment analysis evidenced some altered molecular processes: Cytokine-cytokine receptor interactions, Chemokine signaling, TNF signaling, NOD-like receptor signaling, NF-kappa B signaling, and inflammatory response. With the exception of CXCL12, all enriched genes were downregulated in CCs from patients with endometriosis. These findings provide a significant achievement in the field of reproductive biology, directing future studies to discover biomarkers of oocyte quality in endometriosis.

Tumor necrosis factor-alpha stimulated gene-6: A biomarker reflecting disease activity in rheumatoid arthritis

BACKGROUND

To explore the serum tumor necrosis factor-alpha stimulated gene-6 (TSG-6) level and its association with disease activity in rheumatoid arthritis (RA) patients.

METHODS

We recruited 176 RA patients, 178 non-RA patients (lupus erythematosus, osteoarthritis, ulcerative colitis, ankylosing spondylitis and psoriasis) and 71 healthy subjects. Serum TSG-6 levels were detected by enzyme-linked immunosorbent assay (ELISA). RA patients were divided into inactive RA and active RA groups by disease activity score of 28 joints based on C-reactive protein (DAS28-CRP). The receiver operating characteristic (ROC) curve and Spearman's rank correlation test analyzed the correlation between TSG-6 concentration and RA disease activity.

RESULTS

Tumor necrosis factor-alpha stimulated gene-6 levels in the RA group were increased (p < 0.01). TSG-6 concentrations indicated an upward tendency with increased disease activity; The area under the curve (AUC) of TSG-6 for diagnosing RA and assessing the severity of RA were 0.78 and 0.80, respectively; The combination of TSG-6 and anti-mutated citrullinated vimentin antibodies (anti-MCV) (sensitivity:98.4%)improved the diagnostic accuracy of RA. Binary logistic regression analysis showed that TSG-6 was an independent risk factor related to the severity of RA, and OR (95% CI) was 1.2 (1.003-1.453).

CONCLUSION

The TSG-6 levels in RA patients were elevated and related to disease activity. Therefore, TSG-6 may serve as a new potential biomarker for evaluating RA disease activity.

Single cell transcriptomic landscape of diabetic foot ulcers

Diabetic foot ulceration (DFU) is a devastating complication of diabetes whose pathogenesis remains incompletely understood. Here, we profile 174,962 single cells from the foot, forearm, and peripheral blood mononuclear cells using single-cell RNA sequencing. Our analysis shows enrichment of a unique population of fibroblasts overexpressing MMP1, MMP3, MMP11, HIF1A, CHI3L1, and TNFAIP6 and increased M1 macrophage polarization in the DFU patients with healing wounds. Further, analysis of spatially separated samples from the same patient and spatial transcriptomics reveal preferential localization of these healing associated fibroblasts toward the wound bed as compared to the wound edge or unwounded skin. Spatial transcriptomics also validates our findings of higher abundance of M1 macrophages in healers and M2 macrophages in non-healers. Our analysis provides deep insights into the wound healing microenvironment, identifying cell types that could be critical in promoting DFU healing, and may inform novel therapeutic approaches for DFU treatment.