The Role of Tenascin-C in Tissue Injury and Repair After Stroke

Macrophage plasticity: signaling pathways, tissue repair, and regeneration

Macrophages are versatile immune cells with remarkable plasticity, enabling them to adapt to diverse tissue microenvironments and perform various functions. Traditionally categorized into classically activated (M1) and alternatively activated (M2) phenotypes, recent advances have revealed a spectrum of macrophage activation states that extend beyond this dichotomy. The complex interplay of signaling pathways, transcriptional regulators, and epigenetic modifications orchestrates macrophage polarization, allowing them to respond to various stimuli dynamically. Here, we provide a comprehensive overview of the signaling cascades governing macrophage plasticity, focusing on the roles of Toll-like receptors, signal transducer and activator of transcription proteins, nuclear receptors, and microRNAs. We also discuss the emerging concepts of macrophage metabolic reprogramming and trained immunity, contributing to their functional adaptability. Macrophage plasticity plays a pivotal role in tissue repair and regeneration, with macrophages coordinating inflammation, angiogenesis, and matrix remodeling to restore tissue homeostasis. By harnessing the potential of macrophage plasticity, novel therapeutic strategies targeting macrophage polarization could be developed for various diseases, including chronic wounds, fibrotic disorders, and inflammatory conditions. Ultimately, a deeper understanding of the molecular mechanisms underpinning macrophage plasticity will pave the way for innovative regenerative medicine and tissue engineering approaches.

Construction of lncRNA- and circRNA-associated ceRNA networks in the prostatic urethra of rats after simulating transurethral laser prostatectomy (TULP)

Non-coding RNA appears to be involved in wound repair. Competing endogenous RNA (ceRNA) appears to be an important post-transcriptional mechanism, it means that long noncoding RNA (lncRNA) or circular RNA (circRNA) acts as a microRNA (miRNA) sponge to further regulate mRNA. However, ceRNA network related to wound repair after prostatectomy has yet been constructed. TULP is the main surgical method of prostatectomy, but there have been no reports of TULP rat models in the past. We simulated TULP on rats, and observed the whole process of wound injury and repair after operation through pathological examination of wound tissue. Next, we discovered 732 differentially expressed lncRNAs (DElncRNAs), 47 differentially expressed circRNAs (DEcircRNAs), 17 differentially expressed miRNAs (DEmiRNAs), and 1892 differentially expressed mRNAs (DEmRNAs) related to wound repair after TULP through full transcriptome microarray and bioinformatics methods, and confirmed the reliability of transcriptome data by quantitative Reverse Transcription PCR (qRT-PCR), and immunohistochemistry. Then, we constructed the lncRNA- and circRNA-associated ceRNA regulatory networks related to wound repair after TULP in rats. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses showed that molecules in these networks were mainly involved in inflammatory infiltration, cell differentiation, and intercellular interactions and involved signal pathways such as the PI3K-Akt signaling pathway. Thus, this study successfully established the TULP model in rats, revealed potentially important biomarkers and ceRNA networks after prostatectomy in rats, and provided theoretical support for the repair of post-prostatectomy wound.

The murine metastatic microenvironment of experimental brain metastases of breast cancer differs by host age in vivo: a proteomic study

Breast cancer in young patients is known to exhibit more aggressive biological behavior and is associated with a less favorable prognosis than the same disease in older patients, owing in part to an increased incidence of brain metastases. The mechanistic explanations behind these findings remain poorly understood. We recently reported that young mice, in comparison to older mice, developed significantly greater brain metastases in four mouse models of triple-negative and luminal B breast cancer. Here we have performed a quantitative mass spectrometry-based proteomic analysis to identify proteins potentially contributing to age-related disparities in the development of breast cancer brain metastases. Using a mouse hematogenous model of brain-tropic triple-negative breast cancer (MDA-MB-231BR), we harvested subpopulations of tumor metastases, the tumor-adjacent metastatic microenvironment, and uninvolved brain tissues via laser microdissection followed by quantitative proteomic analysis using high resolution mass spectrometry to characterize differentially abundant proteins potentially contributing to age-dependent rates of brain metastasis. Pathway analysis revealed significant alterations in signaling pathways, particularly in the metastatic microenvironment, modulating tumorigenesis, metabolic processes, inflammation, and neuronal signaling. Tenascin C (TNC) was significantly elevated in all laser microdissection (LMD) enriched compartments harvested from young mice relative to older hosts, which was validated and confirmed by immunoblot analysis of whole brain lysates. Additional in vitro studies including migration and wound-healing assays demonstrated TNC as a positive regulator of tumor cell migration. These results provide important new insights regarding microenvironmental factors, including TNC, as mechanisms contributing to the increased brain cancer metastatic phenotype observed in young breast cancer patients.

Heterogeneity of brain extracellular matrix and astrocyte activation

From the blood brain barrier to the synaptic space, astrocytes provide structural, metabolic, ionic, and extracellular matrix (ECM) support across the brain. Astrocytes include a vast array of subtypes, their phenotypes and functions varying both regionally and temporally. Astrocytes' metabolic and regulatory functions poise them to be quick and sensitive responders to injury and disease in the brain as revealed by single cell sequencing. Far less is known about the influence of the local healthy and aging microenvironments on these astrocyte activation states. In this forward-looking review, we describe the known relationship between astrocytes and their local microenvironment, the remodeling of the microenvironment during disease and injury, and postulate how they may drive astrocyte activation. We suggest technology development to better understand the dynamic diversity of astrocyte activation states, and how basal and activation states depend on the ECM microenvironment. A deeper understanding of astrocyte response to stimuli in ECM-specific contexts (brain region, age, and sex of individual), paves the way to revolutionize how the field considers astrocyte-ECM interactions in brain injury and disease and opens routes to return astrocytes to a healthy quiescent state.

Anti-Apoptotic Effects of AMPA Receptor Antagonist Perampanel in Early Brain Injury After Subarachnoid Hemorrhage in Mice

This study was aimed to investigate if acute neuronal apoptosis is induced by activation of AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionate) receptors (AMPARs) and inhibited by a clinically available selective AMPAR antagonist and antiepileptic drug perampanel (PER) in subarachnoid hemorrhage (SAH), and if the mechanisms include upregulation of an inflammation-related matricellular protein periostin. Sham-operated and endovascular perforation SAH mice randomly received an administration of 3 mg/kg PER or the vehicle intraperitoneally. Post-SAH neurological impairments and increased caspase-dependent neuronal apoptosis were associated with activation of AMPAR subunits GluA1 and GluA2, and upregulation of periostin and proinflammatory cytokines interleukins-1β and -6, all of which were suppressed by PER. PER also inhibited post-SAH convulsion-unrelated increases in the total spectral power on video electroencephalogram (EEG) monitoring. Intracerebroventricularly injected recombinant periostin blocked PER's anti-apoptotic effects on neurons. An intracerebroventricular injection of a selective agonist for GluA1 and GluA2 aggravated neurological impairment, neuronal apoptosis as well as periostin upregulation, but did not increase the EEG total spectral power after SAH. A higher dosage (10 mg/kg) of PER had even more anti-apoptotic effects compared with 3 mg/kg PER. Thus, this study first showed that AMPAR activation causes post-SAH neuronal apoptosis at least partly via periostin upregulation. A clinically available AMPAR antagonist PER appears to be neuroprotective against post-SAH early brain injury through the anti-inflammatory and anti-apoptotic effects, independent of the antiepileptic action, and deserves further study.

Pathophysiological changes of muscle after ischemic stroke: a secondary consequence of stroke injury

Sufficient clinical evidence suggests that the damage caused by ischemic stroke to the body occurs not only in the acute phase but also during the recovery period, and that the latter has a greater impact on the long-term prognosis of the patient. However, current stroke studies have typically focused only on lesions in the central nervous system, ignoring secondary damage caused by this disease. Such a phenomenon arises from the slow progress of pathophysiological studies examining the central nervous system. Further, the appropriate therapeutic time window and benefits of thrombolytic therapy are still controversial, leading scholars to explore more pragmatic intervention strategies. As treatment measures targeting limb symptoms can greatly improve a patient's quality of life, they have become a critical intervention strategy. As the most vital component of the limbs, skeletal muscles have become potential points of concern. Despite this, to the best of our knowledge, there are no comprehensive reviews of pathophysiological changes and potential treatments for post-stroke skeletal muscle. The current review seeks to fill a gap in the current understanding of the pathological processes and mechanisms of muscle wasting atrophy, inflammation, neuroregeneration, mitochondrial changes, and nutritional dysregulation in stroke survivors. In addition, the challenges, as well as the optional solutions for individualized rehabilitation programs for stroke patients based on motor function are discussed.

Harnessing filamentous phages for enhanced stroke recovery

Stroke poses a critical global health challenge, leading to substantial morbidity and mortality. Existing treatments often miss vital timeframes and encounter limitations due to adverse effects, prompting the pursuit of innovative approaches to restore compromised brain function. This review explores the potential of filamentous phages in enhancing stroke recovery. Initially antimicrobial-centric, bacteriophage therapy has evolved into a regenerative solution. We explore the diverse role of filamentous phages in post-stroke neurological restoration, emphasizing their ability to integrate peptides into phage coat proteins, thereby facilitating recovery. Experimental evidence supports their efficacy in alleviating post-stroke complications, immune modulation, and tissue regeneration. However, rigorous clinical validation is essential to address challenges like dosing and administration routes. Additionally, genetic modification enhances their potential as injectable biomaterials for complex brain tissue issues. This review emphasizes innovative strategies and the capacity of filamentous phages to contribute to enhanced stroke recovery, as opposed to serving as standalone treatment, particularly in addressing stroke-induced brain tissue damage.

Biology of Tenascin C and its Role in Physiology and Pathology

Tenascin-C (TNC) is a multimodular extracellular matrix (ECM) protein hexameric with several molecular forms (180-250 kDa) produced by alternative splicing at the pre-mRNA level and protein modifications. The molecular phylogeny indicates that the amino acid sequence of TNC is a well-conserved protein among vertebrates. TNC has binding partners, including fibronectin, collagen, fibrillin-2, periostin, proteoglycans, and pathogens. Various transcription factors and intracellular regulators tightly regulate TNC expression. TNC plays an essential role in cell proliferation and migration. Unlike embryonic tissues, TNC protein is distributed over a few tissues in adults. However, higher TNC expression is observed in inflammation, wound healing, cancer, and other pathological conditions. It is widely expressed in a variety of human malignancies and is recognized as a pivotal factor in cancer progression and metastasis. Moreover, TNC increases both pro-and anti-inflammatory signaling pathways. It has been identified as an essential factor in tissue injuries such as damaged skeletal muscle, heart disease, and kidney fibrosis. This multimodular hexameric glycoprotein modulates both innate and adaptive immune responses regulating the expression of numerous cytokines. Moreover, TNC is an important regulatory molecule that affects the onset and progression of neuronal disorders through many signaling pathways. We provide a comprehensive overview of the structural and expression properties of TNC and its potential functions in physiological and pathological conditions.

A view of the genetic and proteomic profile of extracellular matrix molecules in aging and stroke

Introduction

Modification of the extracellular matrix (ECM) is one of the major processes in the pathology of brain damage following an ischemic stroke. However, our understanding of how age-related ECM alterations may affect stroke pathophysiology and its outcome is still very limited.

Methods

We conducted an ECM-targeted re-analysis of our previously obtained RNA-Seq dataset of aging, ischemic stroke and their interactions in young adult (3-month-old) and aged (18-month-old) mice. The permanent middle cerebral artery occlusion (pMCAo) in rodents was used as a model of ischemic stroke. Altogether 56 genes of interest were chosen for this study.

Results

We identified an increased activation of the genes encoding proteins related to ECM degradation, such as matrix metalloproteinases (MMPs), proteases of a disintegrin and metalloproteinase with the thrombospondin motifs (ADAMTS) family and molecules that regulate their activity, tissue inhibitors of metalloproteinases (TIMPs). Moreover, significant upregulation was also detected in the mRNA of other ECM molecules, such as proteoglycans, syndecans and link proteins. Notably, we identified 8 genes where this upregulation was enhanced in aged mice in comparison with the young ones. Ischemia evoked a significant downregulation in only 6 of our genes of interest, including those encoding proteins associated with the protective function of ECM molecules (e.g., brevican, Hapln4, Sparcl1); downregulation in brevican was more prominent in aged mice. The study was expanded by proteome analysis, where we observed an ischemia-induced overexpression in three proteins, which are associated with neuroinflammation (fibronectin and vitronectin) and neurodegeneration (link protein Hapln2). In fibronectin and Hapln2, this overexpression was more pronounced in aged post-ischemic animals.

Conclusion

Based on these results, we can conclude that the ratio between the protecting and degrading mechanisms in the aged brain is shifted toward degradation and contributes to the aged tissues' increased sensitivity to ischemic insults. Altogether, our data provide fresh perspectives on the processes underlying ischemic injury in the aging brain and serve as a freely accessible resource for upcoming research.

Periostin deficiency attenuates kidney fibrosis in diabetic nephropathy by improving pancreatic β-cell dysfunction and reducing kidney EMT

Diabetic nephropathy (DN) is associated with kidney fibrosis. A previous study revealed that periostin (POSTN) contributes to kidney fibrosis. This study examined the role of POSTN in DN. The urinary concentrations of POSTN and TNC increased according to the severity of DN in human samples. Streptozotocin (STZ) was administered after unilateral nephrectomy (UNXSTZ) to induce DN in wild-type and Postn-null mice. Four experimental groups were generated: wild-typeham (WT Sham), wild-type UNXSTZ (WT STZ), Postn-null Sham (KO Sham), and Postn-null UNXSTZ (KO STZ). After 20 weeks, the KO STZ group had lower levels of urine albumin excretion, glomerular sclerosis, and interstitial fibrosis than those of the WT STZ group. Additionally, the KO STZ group had lower expression of fibrosis markers, including TNC. The KO STZ group showed better glucose regulation than the WT STZ model. Furthermore, the KO STZ group exhibited significantly preserved pancreatic islet integrity and insulin expression. HK-2 cells were used to observe the aggravation of fibrosis caused by POSTN under TGF-β conditions. We stimulated INS-1 cells with streptozotocin and evaluated the viability of these cells. The anti-POSTN antibody treatment of INS-1 cells with streptozotocin resulted in higher cell viability than that with treatment with streptozotocin alone. The absence of POSTN in DN contributes to renal fibrosis alleviation by improving pancreatic β-cell function. Additionally, there is an association between POSTN and TNC.

Mass spectrometry methods for analysis of extracellular matrix components in neurological diseases

The brain extracellular matrix (ECM) is a highly glycosylated environment and plays important roles in many processes including cell communication, growth factor binding, and scaffolding. The formation of structures such as perineuronal nets (PNNs) is critical in neuroprotection and neural plasticity, and the formation of molecular networks is dependent in part on glycans. The ECM is also implicated in the neuropathophysiology of disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), and Schizophrenia (SZ). As such, it is of interest to understand both the proteomic and glycomic makeup of healthy and diseased brain ECM. Further, there is a growing need for site-specific glycoproteomic information. Over the past decade, sample preparation, mass spectrometry, and bioinformatic methods have been developed and refined to provide comprehensive information about the glycoproteome. Core ECM molecules including versican, hyaluronan and proteoglycan link proteins, and tenascin are dysregulated in AD, PD, and SZ. Glycomic changes such as differential sialylation, sulfation, and branching are also associated with neurodegeneration. A more thorough understanding of the ECM and its proteomic, glycomic, and glycoproteomic changes in brain diseases may provide pathways to new therapeutic options.

Co-administration of extracellular matrix-based biomaterials with neural stem cell transplantation for treatment of central nervous system injury

Injuries and disorders of the central nervous system (CNS) present a particularly difficult challenge for modern medicine to address, given the complex nature of the tissues, obstacles in researching and implementing therapies, and barriers to translating efficacious treatments into human patients. Recent advancements in neural stem cell (NSC) transplantation, endogenous neurogenesis, and in vivo reprogramming of non-neural cells into the neuronal lineage represent multiple approaches to resolving CNS injury. However, we propose that one practice that must be incorporated universally in neuroregeneration studies is the use of extracellular matrix (ECM)-mimicking biomaterials to supply the architectural support and cellular microenvironment necessary for partial or complete restoration of function. Through consideration of developmental processes including neurogenesis, cellular migration, and establishment of functional connectivity, as well as evaluation of process-specific interactions between cells and ECM components, insights can be gained to harness and modulate native and induced neurobiological processes to promote CNS tissue repair. Further, evaluation of the current landscape of regenerative medicine and tissue engineering techniques external to the neurosciences provides key perspectives into the role of the ECM in the use of stem cell-based therapies, and the potential directions future neuroregenerative approaches may take. If the most successful of these approaches achieve wide-spread adoption, innovative paired NSC-ECM strategies for neuroregeneration may become prominent in the near future, and with the rapid advances these techniques are poised to herald, a new era of treatment for CNS injury may dawn.

Evaluation of Tenascin Expression in Ameloblastoma, Odontogenic Keratocyst, and Dentigerous Cyst by Immunohistochemistry

Background

The aim of this study was to evaluate the expression pattern of tenascin in ameloblastoma, odontogenic keratocyst, and dentigerous cyst.

Materials and Methods

The expression of tenascin was evaluated in microscopic slides of 42 paraffin blocks including 12 ameloblastomas, 15 odontogenic keratocysts, and 15 dentigerous cysts by immunohistochemistry. The expression of tenascin was examined in stroma, epithelium-connective tissue interface, and epithelium of the lesions by two pathologists semiquantitatively.

Results

Stromal expression of tenascin was higher in ameloblastomas than other groups. All the paired groups showed significant differences except comparison of odontogenic keratocysts and dentigerous cysts. Epithelial-mesenchymal interface expression of tenascin was significantly higher in ameloblastomas and odontogenic keratocysts than dentigerous cysts. All the paired groups showed significant differences except comparison of odontogenic keratocysts and ameloblastomas. Expression of tenascin in epithelial cells of ameloblastomas was focal whereas in odontogenic keratocysts and dentigerous cysts negative immunoreactivity was reported.

Conclusions

Expression of tenascin in these lesions suggests that it could play a role in epithelial-mesenchymal interaction. Higher expression of tenascin in ameloblastoma, can explain immaturity of its stroma and aggressive nature of this lesion compared with other studied groups. Moreover, higher expression of tenascin in epithelial-mesenchymal interface of odontogenic keratocyst compared with dentigerous cyst reveals its more immature and aggressive nature and high rate of recurrence.

Validating a Proteomic Signature of Severe COVID-19

COVID-19 is a heterogenous disease. Biomarker-based approaches may identify patients at risk for severe disease, who may be more likely to benefit from specific therapies. Our objective was to identify and validate a plasma protein signature for severe COVID-19.

DESIGN

Prospective observational cohort study.

SETTING

Two hospitals in the United States.

PATIENTS

One hundred sixty-seven hospitalized adults with COVID-19.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

We measured 713 plasma proteins in 167 hospitalized patients with COVID-19 using a high-throughput platform. We classified patients as nonsevere versus severe COVID-19, defined as the need for high-flow nasal cannula, mechanical ventilation, extracorporeal membrane oxygenation, or death, at study entry and in 7-day intervals thereafter. We compared proteins measured at baseline between these two groups by logistic regression adjusting for age, sex, symptom duration, and comorbidities. We used lead proteins from dysregulated pathways as inputs for elastic net logistic regression to identify a parsimonious signature of severe disease and validated this signature in an external COVID-19 dataset. We tested whether the association between corticosteroid use and mortality varied by protein signature. One hundred ninety-four proteins were associated with severe COVID-19 at the time of hospital admission. Pathway analysis identified multiple pathways associated with inflammatory response and tissue repair programs. Elastic net logistic regression yielded a 14-protein signature that discriminated 90-day mortality in an external cohort with an area under the receiver-operator characteristic curve of 0.92 (95% CI, 0.88-0.95). Classifying patients based on the predicted risk from the signature identified a heterogeneous response to treatment with corticosteroids (p = 0.006).

CONCLUSIONS

Inpatients with COVID-19 express heterogeneous patterns of plasma proteins. We propose a 14-protein signature of disease severity that may have value in developing precision medicine approaches for COVID-19 pneumonia.

Matricellular proteins in cutaneous wound healing

Cutaneous wound healing is a complex process that encompasses alterations in all aspects of the skin including the extracellular matrix (ECM). ECM consist of large structural proteins such as collagens and elastin as well as smaller proteins with mainly regulative properties called matricellular proteins. Matricellular proteins bind to structural proteins and their functions include but are not limited to interaction with cell surface receptors, cytokines, or protease and evoking a cellular response. The signaling initiated by matricellular proteins modulates differentiation and proliferation of cells having an impact on the tissue regeneration. In this review we give an overview of the matricellular proteins that have been found to be involved in cutaneous wound healing and summarize the information known to date about their functions in this process.

Concomitant elevated serum levels of tenascin, MMP-9 and YKL-40, suggest ongoing remodeling of the heart up to 3 months after cardiac surgery after normalization of the revascularization markers

BACKGROUND

The recovery from cardiac surgery involves resolving inflammation and remodeling with significant connective tissue turnover. Dynamics of smoldering inflammation and injury (white blood cells, platelets, CRP, IL-8, IL-6), vascular inflammation (IL-15, VEGF, RANTES), connective tissue remodeling (tenascin, MMP-9), cardiac injury and remodeling (YKL-40), and vascular remodeling (epiregulin, MCP-1, VEGF) were assessed up to 3 months after cardiac surgery. We hypothesize that at 3 months, studied markers will return to pre-surgical levels.

METHODS

Patients (n = 139) scheduled for non-emergent heart surgery were included, except for patients with pre-existing immunological aberrancies. Blood was collected before surgery(t_baseline), 24 h later(t_24h) after the first sample, 7 days(t_7d), and 3 months(t_3m) after t_baseline. Serum markers were measured via multiplex or ELISA. Electronic medical records (EMR) were used to extract demographical, pre-existing conditions and clinical data. Disposition (discharge home, discharge to facility, death, re-admission) was determined at 28 days and 3 months from admission.

RESULTS

Not all inflammatory markers returned to baseline (CRP↑↑, leukocytosis, thrombocytosis, IL-8↓, IL-6↓). Tenascin and YKL-40 levels remained elevated even at t_3m. YKL-40 serum levels were significantly elevated at t_24h and t_7d while normalized at t_3m. VEGF returned to the baseline, yet MCP-1 remained elevated at 3 months. CCL28 increased at 3 months, while RANTES and IL-15 declined at the same time. Disposition at discharge was determined by serum MMP-9, while YKL-40 correlated with duration of surgery and APACHE II_24h.

CONCLUSIONS

The data demonstrated an ongoing extracellular matrix turnover at 3 months, while acute inflammation and vascular remodeling resolved only partially.

The role of the astrocyte in subarachnoid hemorrhage and its therapeutic implications

Subarachnoid hemorrhage (SAH) is an important public health concern with high morbidity and mortality worldwide. SAH induces cell death, blood−brain barrier (BBB) damage, brain edema and oxidative stress. As the most abundant cell type in the central nervous system, astrocytes play an essential role in brain damage and recovery following SAH. This review describes astrocyte activation and polarization after SAH. Astrocytes mediate BBB disruption, glymphatic–lymphatic system dysfunction, oxidative stress, and cell death after SAH. Furthermore, astrocytes engage in abundant crosstalk with other brain cells, such as endothelial cells, neurons, pericytes, microglia and monocytes, after SAH. In addition, astrocytes also exert protective functions in SAH. Finally, we summarize evidence regarding therapeutic approaches aimed at modulating astrocyte function following SAH, which could provide some new leads for future translational therapy to alleviate damage after SAH.

Persistent Depletion of Neuroprotective Factors Accompanies Neuroinflammatory, Neurodegenerative, and Vascular Remodeling Spectra in Serum Three Months after Non-Emergent Cardiac Surgery

We hypothesized that the persistent depletion of neuroprotective markers accompanies neuroinflammation and neurodegeneration in patients after cardiac surgery. A total of 158 patients underwent elective heart surgery with their blood collected before surgery (tbaseline) and 24 h (t24hr), seven days (t7d), and three months (t3m) post-surgery. The patients' serum was measured for markers of neurodegeneration (τau, τaup181-183, amyloid β1-40/β2-42, and S100), atypical neurodegeneration (KLK6 and NRGN), neuro-injury (neurofilament light/heavy, UC-HL, and GFAP), neuroinflammation (YKL-40 and TDP-43), peripheral nerve damage (NCAM-1), neuroprotection (apoE4, BDNF, fetuin, and clusterin), and vascular smoldering inflammation (C-reactive protein, CCL-28 IL-6, and IL-8). The mortality at 28 days, incidence of cerebrovascular accidents (CVA), and functional status were followed for three months. The levels of amyloid β1-40/β1-42 and NF-L were significantly elevated at all time points. The levels of τau, S100, KLK6, NRGN, and NCAM-1 were significantly elevated at 24 h. A cluster analysis demonstrated groupings around amyloids, KLK6, and NCAM-1. YKL-40, but not TDP-43, was significantly elevated across all time points. BDNF, apoE4, fetuin, and clusterin levels were significantly diminished long-term. IL-6 and IL-8 levles returned to baseline at t3m. The levels of CRP, CCL-28, and Hsp-70 remained elevated. At 3 months, 8.2% of the patients experienced a stroke, with transfusion volume being a significant variable. Cardiac-surgery patients exhibited persistent peripheral and neuronal inflammation, blood vessel remodeling, and the depletion of neuroprotective factors 3 months post-procedure.

Tenascin-C fibronectin D domain is involved in the fine-tuning of glial response to CNS injury in vitro

Understanding processes that occur after injuries to the central nervous system is essential in order to gain insight into how the restoration of function can be improved. Extracellular glycoprotein tenascin-C (TnC) has numerous functions in wound healing process depending on the expression time, location, isoform and binding partners which makes it interesting to study in this context. We used an in vitro injury model, the mixed culture of cortical astrocytes and microglia, and observed that without TnC microglial cells tend to populate gap area in greater numbers and proliferate more, whereas astrocytes build up in the border region to promote faster gap closure. Alternatively spliced domain of TnC, fibronectin type III-like repeat D (FnD) strongly affected physiological properties and morphology of both astrocytes and microglia in this injury model. The rate of microglial proliferation in the injury region decreased significantly with the addition of FnD. Additionally, density of microglia also decreased, in part due to reduced proliferation, and possibly due to reduced migration and increased contact inhibition between enlarged FnD-treated cells. Overall morphology of FnD-treated microglia resembled the activated pro-inflammatory cells, and elevated expression of iNOS was in accordance with this phenotype. The effect of FnD on astrocytes was different, as it did not affect their proliferation, but stimulated migration of reactivated astrocytes into the scratched area 48 h after the lesion. Elevated expression and secretion of TNF-α and IL-1β upon FnD treatment indicated the onset of inflammation. Furthermore, on Western blots we observed increased intensity of precursor bands of β1 integrin and appearance of monomeric bands of P2Y12R after FnD treatment which substantiates and clarifies its role in cellular shape and motility changes. Our results show versatile functions of TnC and in particular FnD after injury, mostly contributing to ongoing inflammation in the injury region. Based on our findings, FnD might be instrumental in limiting immune cell infiltration, and promoting astrocyte migration within the injury region, thus influencing spaciotemporal organization of the wound and surrounding area.

Matricellular protein tenascin C: Implications in glioma progression, gliomagenesis, and treatment

Matricellular proteins are nonstructural extracellular matrix components that are expressed at low levels in normal adult tissues and are upregulated during development or under pathological conditions. Tenascin C (TNC), a matricellular protein, is a hexameric and multimodular glycoprotein with different molecular forms that is produced by alternative splicing and post-translational modifications. Malignant gliomas are the most common and aggressive primary brain cancer of the central nervous system. Despite continued advances in multimodal therapy, the prognosis of gliomas remains poor. The main reasons for such poor outcomes are the heterogeneity and adaptability caused by the tumor microenvironment and glioma stem cells. It has been shown that TNC is present in the glioma microenvironment and glioma stem cell niches, and that it promotes malignant properties, such as neovascularization, proliferation, invasiveness, and immunomodulation. TNC is abundantly expressed in neural stem cell niches and plays a role in neurogenesis. Notably, there is increasing evidence showing that neural stem cells in the subventricular zone may be the cells of origin of gliomas. Here, we review the evidence regarding the role of TNC in glioma progression, propose a potential association between TNC and gliomagenesis, and summarize its clinical applications. Collectively, TNC is an appealing focus for advancing our understanding of gliomas.

Shared Inflammatory Pathology of Stroke and COVID-19

Though COVID-19 is primarily characterized by symptoms in the periphery, it can also affect the central nervous system (CNS). This has been established by the association between stroke and COVID-19. However, the molecular mechanisms that cause stroke related to a COVID-19 infection have not been fully explored. More specifically, stroke and COVID-19 exhibit an overlap of molecular mechanisms. These similarities provide a way to better understand COVID-19 related stroke. We propose here that peripheral macrophages upregulate inflammatory proteins such as matrix metalloproteinases (MMPs) in response to SARS-CoV-2 infection. These inflammatory molecules and the SARS-CoV-2 virus have multiple negative effects related to endothelial dysfunction that results in the disruption of the blood-brain barrier (BBB). Finally, we discuss how the endothelial blood-brain barrier injury alters central nervous system function by leading to astrocyte dysfunction and inflammasome activation. Our goal is to elucidate such inflammatory pathways, which could provide insight into therapies to combat the negative neurological effects of COVID-19.

Mesangial Cell-Derived Tenascin-C Contributes to Mesangial Cell Proliferation and Matrix Protein Production in IgA Nephropathy

AIM

Tenascin-C (TNC), a non-structural extracellular matrix glycoprotein, is transiently expressed during development or after injury, playing an important role in injury and repair process. The potential role of TNC in the pathogenesis of IgA nephropathy (IgAN) remains to be clarified.

METHODS

Immunohistochemistry staining for TNC was conducted on paraffin-embedded slices from renal biopsies of 107 IgAN patients, and correlation analysis was made between mesangial TNC expression and clinic-pathological parameters. In situ hybridization for TNC mRNA was further performed to figure out the cells that express TNC within glomeruli. In vitro experiments were also carried out on mouse mesangial cells (SV40 MES13) to elucidate the effect of TNC on mesangial cells.

RESULTS

TNC was expressed in the mesangial area of IgAN, as well as in fibrotic regions. Correlation analysis showed that higher mesangial TNC was associated with higher level of proteinuria, lower eGFR and more serious pathological lesions (MEST score). In situ hybridization revealed that abundant TNC mRNA expression was observed in the affected glomeruli of IgAN, but not in minimal change disease (MCD). Moreover, TNC mRNA co-localized with PDGFRβ mRNA, but not with PODXL mRNA, suggesting that TNC mRNA was expressed in the mesangial cells within glomeruli in IgAN. In vitro experiments showed that exogenous TNC promoted matrix protein production and mesangial cell proliferation, which was attenuated by an EGFR inhibitor.

CONCLUSION

Taken together, these results suggest that mesangial cell-derived TNC contributes to mesangial matrix expansion and mesangial cell proliferation, which is a potential therapeutic target in IgAN.

Tenascin-C induction exacerbates post-stroke brain damage

The role of tenascin-C (TNC) in ischemic stroke pathology is not known despite its prognostic association with cerebrovascular diseases. Here, we investigated the effect of TNC knockdown on post-stroke brain damage and its putative mechanism of action in adult mice of both sexes. Male and female C57BL/6 mice were subjected to transient middle cerebral artery occlusion and injected (i.v.) with either TNC siRNA or a negative (non-targeting) siRNA at 5 min after reperfusion. Motor function (beam walk and rotarod tests) was assessed between days 1 and 14 of reperfusion. Infarct volume (T2-MRI), BBB damage (T1-MRI with contrast), and inflammatory markers were measured at 3 days of reperfusion. The TNC siRNA treated cohort showed significantly curtailed post-stroke TNC protein expression, motor dysfunction, infarction, BBB damage, and inflammation compared to the sex-matched negative siRNA treated cohort. These results demonstrate that the induction of TNC during the acute period after stroke might be a mediator of post-ischemic inflammation and secondary brain damage independent of sex.

Serum Tenascin-C and Alarin Levels Are Associated with Cardiovascular Diseases in Type 2 Diabetes Mellitus

BACKGROUND

Tenascin-C (TNC), an extracellular matrix glycoprotein, is elevated in inflammatory and cardiovascular pathologies, whereas alarin, a novel orexigenic peptide, participates in insulin resistance and glycometabolism. The roles of these molecules in individuals with cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM), clinical conditions associating with metabolic disorders, and chronic inflammation, remain controversial. Our study aimed at determining the potential role of TNC and alarin in CVD adult patients with T2DM.

METHODS

This was a cross-sectional study. Basic and clinical information for 250 patients with T2DM were analyzed. Based on their cardiovascular disease status, participants were assigned into the CVD and non-CVD groups. Serum TNC and alarin levels were assessed by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Serum TNC and alarin concentrations in the CVD group were significantly higher than those of the non-CVD group. Moreover, serum TNC levels were positively correlated with age, waist circumference, and waist-hip ratio; however, they were negatively correlated with TC, LDL-C, and eGFR levels. Alarin levels were positively correlated with BMI, waist circumference, and hip circumference. In logistic regression models, TNC and alarin were also established to be independent determinants for CVD in T2DM patients and their increases were associated with CVD severity. Receiver operating characteristic (ROC) curve analysis showed that the area under curve (AUC) values for TNC and alarin were 0.68 and 0.67, respectively. TNC and alarin were good predictors of CVD occurrence. When the cutoff value for TNC was 134.05 pg/mL, its sensitivity was 69.47% while its specificity was 61.29%. When the cutoff value for alarin was 142.69 pg/mL, sensitivity and specificity were 38.95% and 90.97%, respectively.

CONCLUSION

Elevated TNC and alarin levels are independently associated with the occurrence and severity of CVD in T2DM individuals. Therefore, these two biomarkers are potential diagnostic and prognostic indicators for CVD in diabetics.

Single Cell Genomics Identifies Unique Cardioprotective Phenotype of Stem Cells derived from Epicardial Adipose Tissue under Ischemia

The conventional management strategies of myocardial infarction (MI) are effective to sustain life; however, myocardial regeneration has not been achieved owing to the inherently poor regenerative capacity of the native myocardium. Stem cell-based therapies are promising; however, lineage specificity and undesired differentiation profile are challenging. Herein, we focused on the epicardial fat (EF) as an ideal source for mesenchymal stem cells (MSCs) owing to the proximity and same microvasculature with cardiac muscle. Unfortunately, the epicardial adipose tissue derived stem cells (EATDS) remain understudied regarding their phenotype heterogeneity and cardiac regeneration potential. As EF closely reflects the cardiac pathology during ischemia, the present study aims to determine the EATDS subpopulations under simulated ischemic and reperfused conditions employing single cell RNA sequencing (scRNAseq). EATDS were isolated from three hyperlipidemic Yucatan microswine and were divided into Control, Ischemia (ISC), and Ischemia/reperfusion (ISC/R). The scRNAseq analysis was performed using 10 genomics platform which revealed 18 unique cell clusters suggesting the existence of heterogeneous phenotypes. The upregulated genes were taken into consideration and subsequent functional assessment revealed the cardioprotective phenotypes with diverse mechanisms including epigenetic regulation (Cluster 1), myocardial homeostasis (Cluster 1), cell integrity and cell cycle (Clusters 2 and 3), prevention of fibroblast differentiation (Cluster 4), differentiation to myocardial lineage (Cluster 6), anti-inflammatory responses (Clusters 5, 8, and 11), prevention of ER-stress (Cluster 9), and increasing the energy metabolism (Cluster 10). These unique phenotypes of heterogeneous EATDS population open significant translational opportunities for myocardial regeneration and cardiac management.

Involvement of integrin-activating peptides derived from tenascin-C in colon cancer progression

Tenascin-C (TNC) is an adhesion modulatory protein present in the extracellular matrix that is highly expressed in several malignancies, including colon cancer. Although TNC is considered a negative prognostic factor for cancer patients, the substantial role of the TNC molecule in colorectal carcinogenesis and its malignant progression is poorly understood. We previously found that TNC has a cryptic functional site and that a TNC peptide containing this site, termed TNIIIA2, can potently and persistently activate beta1-integrins. In contrast, the peptide FNIII14, which contains a cryptic bioactive site within the fibronectin molecule, can inactivate beta1-integrins. This review presents the role of TNC in the development of colitis-associated colorectal cancer and in the malignant progression of colon cancer, particularly the major involvement of its cryptic functional site TNIIIA2. We propose new possible prophylactic and therapeutic strategies based on inhibition of the TNIIIA2-induced beta1-integrin activation by peptide FNIII14.

Beyond the GFAP-Astrocyte Protein Markers in the Brain

The idea of central nervous system as one-man band favoring neurons is long gone. Now we all are aware that neurons and neuroglia are team players and constant communication between those various cell types is essential to maintain functional efficiency and a quick response to danger. Here, we summarize and discuss known and new markers of astroglial multiple functions, their natural heterogeneity, cellular interactions, aging and disease-induced dysfunctions. This review is focused on newly reported facts regarding astrocytes, which are beyond the old stereotypes. We present an up-to-date list of marker proteins used to identify a broad spectrum of astroglial phenotypes related to the various physiological and pathological nervous system conditions. The aim of this review is to help choose markers that are well-tailored for specific needs of further experimental studies, precisely recognizing differential glial phenotypes, or for diagnostic purposes. We hope it will help to categorize the functional and structural diversity of the astroglial population and ease a clear readout of future experimental results.

Evaluation of the serum levels of Mannose binding lectin-2, tenascin-C, and total antioxidant capacity in patients with coronary artery disease

Background

Coronary artery disease (CAD) develops as a result of atherosclerosis. Atherosclerosis is a condition that leads to clogged arteries and can be caused by a variety of factors. Several studies have shown that various factors contribute to the development and progression of CAD. The aim of this study was to investigate the serum levels of MBL‐2, TNC and TAC in patients with CAD and the relationship between these biochemical parameters and the progression of CAD.

Methods

In this study, 60 serum samples were obtained from CAD patients as the case group and 20 healthy serum samples as the control group. Serum levels of MBL‐2 and TNC were measured by the ELISA method. Serum TAC level was determined by calorimetry (spectrophotometry). In addition, MDA serum level was measured by reaction with thiobarbituric acid (TBA).

Results

The mean age in the case and control groups was 58.4 ± 9.5 years and 85 ± 9.8 years, respectively. There was no significant difference in age, sex and family history in patients with CAD (p > 0.05), but there was a significant difference in blood pressure and smoking history (p > 0.05). Serum cholesterol, triglyceride, and LDL levels were significantly increased in the case group compared to the control group, while serum HDL‐C levels were significantly decreased in the case group. Serum levels of MBL‐2, TNC, and MDA were significantly increased in the case group compared to the control group. The serum level of TAC was significantly lower in the case group than in the control group.

Conclusion

This study suggests that it is possible to diagnose patients with coronary artery disease (CAD) in the early stages of their disease and take preventive measures by measuring these parameters in serum. However, more research is needed before these serum parameters can be considered diagnostic biomarkers or therapeutic targets.

Tenascin-C in Heart Diseases-The Role of Inflammation

Tenascin-C (TNC) is a large extracellular matrix (ECM) glycoprotein and an original member of the matricellular protein family. TNC is transiently expressed in the heart during embryonic development, but is rarely detected in normal adults; however, its expression is strongly up-regulated with inflammation. Although neither TNC-knockout nor -overexpressing mice show a distinct phenotype, disease models using genetically engineered mice combined with in vitro experiments have revealed multiple significant roles for TNC in responses to injury and myocardial repair, particularly in the regulation of inflammation. In most cases, TNC appears to deteriorate adverse ventricular remodeling by aggravating inflammation/fibrosis. Furthermore, accumulating clinical evidence has shown that high TNC levels predict adverse ventricular remodeling and a poor prognosis in patients with various heart diseases. Since the importance of inflammation has attracted attention in the pathophysiology of heart diseases, this review will focus on the roles of TNC in various types of inflammatory reactions, such as myocardial infarction, hypertensive fibrosis, myocarditis caused by viral infection or autoimmunity, and dilated cardiomyopathy. The utility of TNC as a biomarker for the stratification of myocardial disease conditions and the selection of appropriate therapies will also be discussed from a clinical viewpoint.