Hyaluronan fragments stimulate endothelial recognition of injury through TLR4

35kDa SPECIFIC-SIZED HYALURONAN AMELIORATES HIGH-FAT DIET-INDUCED LIVER INJURY IN MURINE MODEL OF MODERATE OBESITY

Obesity is a growing concern in the US and world-wide, associated with an increased risk for several cardiometabolic diseases, including metabolic associated steatotic liver disease (MASLD). Currently, therapeutic interventions to prevent and/or treat MASLD are limited, and research is needed to identify new therapeutic targets. The specific-sized 35kDa fragment of hyaluronan (HA35), has gut protective and anti-inflammatory properties and a previous pilot clinical study reported it is well tolerated in healthy individuals. Here we tested the hypothesis that HA35 treatment ameliorates high fat diet-induced liver injury. Five-week-old male C57BL/6J mice were allowed ad lib access to control chow or high fat fructose and cholesterol (FFC) diet over a period of 12 weeks. HA35 was administered at 15mg/kg via oral gavage on the last 6 days of the study as a therapeutic intervention. Mice on FFC diet-gained more body weight compared to those on chow diet, with final body weights ranging from 30.8-45.6 g. FFC diet caused hepatocyte injury, increased expression of inflammatory cytokine/chemokine mRNA, as well as indicators of liver fibrosis. When mice were stratified based on their final body weight, only mice <40g were protected by treatment with HA35. In this group, treatment with HA35 also restored tight junction integrity in the colon and increased expression of α -defensins in the small intestine. Taken together the data suggests that HA35 is an effective therapeutic in ameliorating high fat diet-induced liver inflammation and fibrosis in moderately obese, but not severe, conditions.

Comparative evaluation of hyaluronic acid-based dressing versus hydrocolloid dressing in rat dermal wound healing

BACKGROUND

Wound healing is a complex process influenced by a variety of environmental factors. Dressing materials play a critical role in creating barriers against contaminants, maintaining optimal moisture levels, and absorbing wound exudate. Therefore, selecting materials tailored to wound characteristics is crucial for enhancing outcomes. Hyaluronic acid (HA) is a natural biocompatible polymer that supports healing by regulating inflammation and promoting tissue repair. This study compared HA- and hydrocolloid-based hydrogels in a rat model to optimize wound care strategies.

METHODS

Full-thickness dermal wounds (diameter, 8 mm) were created on the dorsal skin of 12 Sprague-Dawley rats under sevoflurane anesthesia. The wounds were treated with HA/silver sulfadiazine gel (group A), hydrocolloid gel (group B), or left untreated (control), all covered with a transparent dressing. Biopsy specimens on days 3, 7, and 21 were used to assess histological parameters: inflammatory cell infiltration, fibroblast infiltration, collagen deposition, neovascularization, and epithelial thickness, using a semi-quantitative scoring system. Histological analyses were conducted blindly, and statistical analyses were performed using the Kruskal-Wallis test (p< 0.05).

RESULTS

On day 3, group A showed significantly higher inflammatory cell infiltration and collagen deposition than other groups, indicating extracellular matrix formation. By day 7, angiogenesis was highest in group A, followed by group B and controls. By day 21, all wounds had completely healed. Epithelial layer thickness, reflecting inflammation and fibroblast maturity, was significantly higher in group A.

CONCLUSION

This study compared HA-based hydrogel and hydrocolloid-based dressings through histological analyses to elucidate wound healing mechanics. HA-based hydrogel dressings significantly enhanced wound recovery. However, generalizing these outcomes requires future studies to expand the range of effective wound treatment materials. These findings underscore the potential of HA-based dressings to enhance clinical outcomes in wound management, suggesting avenues for improving therapeutic strategies.

Unraveling neurovascular mysteries: the role of endothelial glycocalyx dysfunction in Alzheimer's disease pathogenesis

While cardiovascular disease, cancer, and human immunodeficiency virus (HIV) mortality rates have decreased over the past 20 years, Alzheimer's Disease (AD) deaths have risen by 145% since 2010. Despite significant research efforts, effective AD treatments remain elusive due to a poorly defined etiology and difficulty in targeting events that occur too downstream of disease onset. In hopes of elucidating alternative treatment pathways, now, AD is commonly being more broadly defined not only as a neurological disorder but also as a progression of a variety of cerebrovascular pathologies highlighted by the breakdown of the blood-brain barrier. The endothelial glycocalyx (GCX), which is an essential regulator of vascular physiology, plays a crucial role in the function of the neurovascular system, acting as an essential vascular mechanotransducer to facilitate ultimate blood-brain homeostasis. Shedding of the cerebrovascular GCX could be an early indication of neurovascular dysfunction and may subsequently progress neurodegenerative diseases like AD. Recent advances in in vitro modeling, gene/protein silencing, and imaging techniques offer new avenues of scrutinizing the GCX's effects on AD-related neurovascular pathology. Initial studies indicate GCX degradation in AD and other neurodegenerative diseases and have begun to demonstrate a possible link to GCX loss and cerebrovascular dysfunction. This review will scrutinize the GCX's contribution to known vascular etiologies of AD and propose future work aimed at continuing to uncover the relationship between GCX dysfunction and eventual AD-associated neurological deterioration.

Dose-Dependent Effects of Lipopolysaccharide on the Endothelium-Sepsis versus Metabolic Endotoxemia-Induced Cellular Senescence

The endothelium, the innermost cell layer of blood vessels, is not only a physical barrier between the bloodstream and the surrounding tissues but has also essential functions in vascular homeostasis. Therefore, it is not surprising that endothelial dysfunction is associated with most cardiovascular diseases. The functionality of the endothelium is compromised by endotoxemia, the presence of bacterial endotoxins in the bloodstream with the main endotoxin lipopolysaccharide (LPS). Therefore, this review will focus on the effects of LPS on the endothelium. Depending on the LPS concentration, the outcomes are either sepsis or, at lower concentrations, so-called low-dose or metabolic endotoxemia. Sepsis, a life-threatening condition evoked by hyperactivation of the immune response, includes breakdown of the endothelial barrier resulting in failure of multiple organs. A deeper understanding of the underlying mechanisms in the endothelium might help pave the way to new therapeutic options in sepsis treatment to prevent endothelial leakage and fatal septic shock. Low-dose endotoxemia or metabolic endotoxemia results in chronic inflammation leading to endothelial cell senescence, which entails endothelial dysfunction and thus plays a critical role in cardiovascular diseases. The identification of compounds counteracting senescence induction in endothelial cells might therefore help in delaying the onset or progression of age-related pathologies. Interestingly, two natural plant-derived substances, caffeine and curcumin, have shown potential in preventing endothelial cell senescence.

Toll-like receptor 4 in pancreatic damage and immune infiltration in acute pancreatitis

Acute pancreatitis is a complex inflammatory disease resulting in extreme pain and can result in significant morbidity and mortality. It can be caused by several factors ranging from genetics, alcohol use, gall stones, and ductal obstruction caused by calcification or neutrophil extracellular traps. Acute pancreatitis is also characterized by immune cell infiltration of neutrophils and M1 macrophages. Toll-like receptor 4 (TLR4) is a pattern recognition receptor that has been noted to respond to endogenous ligands such as high mobility group box 1 (HMGB1) protein and or exogenous ligands such as lipopolysaccharide both of which can be present during the progression of acute pancreatitis. This receptor can be found on a variety of cell types from endothelial cells to resident and infiltrating immune cells leading to production of pro-inflammatory cytokines as well as immune cell activation and maturation resulting in the furthering of pancreatic damage during acute pancreatitis. In this review we will address the various mechanisms mediated by TLR4 in the advancement of acute pancreatitis and how targeting this receptor could lead to improved outcomes for patients suffering from this condition.

The role of immune system in atherosclerosis: Molecular mechanisms, controversies, and future possibilities

Numerous cardiovascular disorders have atherosclerosis as their pathological underpinning. Numerous studies have demonstrated that, with the aid of pattern recognition receptors, cytokines, and immunoglobulins, innate immunity, represented by monocytes/macrophages, and adaptive immunity, primarily T/B cells, play a critical role in controlling inflammation and abnormal lipid metabolism in atherosclerosis. Additionally, the finding of numerous complement components in atherosclerotic plaques suggests yet again how heavily the immune system controls atherosclerosis. Therefore, it is essential to have a thorough grasp of how the immune system contributes to atherosclerosis. The specific molecular mechanisms involved in the activation of immune cells and immune molecules in atherosclerosis, the controversy surrounding some immune cells in atherosclerosis, and the limitations of extrapolating from relevant animal models to humans were all carefully reviewed in this review from the three perspectives of innate immunity, adaptive immunity, and complement system. This could provide fresh possibilities for atherosclerosis research and treatment in the future.

Nanotechnology Platform for Advancing Vaccine Development against the COVID-19 Virus

The COVID-19 pandemic has had a profound impact on societies, public health, healthcare systems, and the world economy. With over 771 million people infected worldwide and a staggering death toll exceeding 6,960,783 as of 4 October 2023 (according to the World Health Organization), the urgency for a solution was paramount. Since the outbreak, the demand for immediate treatment for COVID-19 viral infection, as well as for effective vaccination against this virus, was soaring, which led scientists, pharmaceutical/biotech companies, government health agencies, etc., to think about a treatment strategy that could control and minimize this outbreak as soon as possible. Vaccination emerged as the most effective strategy to combat this infectious disease. For vaccination strategies, any conventional vaccine approach using attenuated live or inactivated/engineered virus, as well as other approaches, typically requires years of research and assessment. However, the urgency of the situation promoted a faster and more effective approach to vaccine development against COVID-19. The role of nanotechnology in designing, manufacturing, boosting, and delivering vaccines to the host to counter this virus was unquestionably valued and assessed. Several nanoformulations are discussed here in terms of their composition, physical properties, credibility, and applications in past vaccine development (as well as the possibility of using those used in previous applications for the generation of the COVID-19 vaccine). Controlling and eliminating the spread of the virus and preventing future recurrence requires a safe, tolerable, and effective vaccine strategy. In this review, we discuss the potential of nanoformulations as the basis for an effective vaccine strategy against COVID-19.

Attenuated Replication-Competent Herpes Simplex Virus Expressing an ECM-Modifying Transgene Hyaluronan Synthase 2 of Naked Mole Rat in Oncolytic Gene Therapy

Herpes simplex virus (HSV) has proven successful in treating human cancer. Since the approval of talimogene laherparepvec (T-VEC) in 2015, HSV has been thoroughly researched to discover novel mechanisms to combat cancer and treat other diseases. Another HSV-based drug, beremagene geperpavec (B-VEC), received approval in 2023 to treat the rare genetic disease dystrophic epidermolysis bullosa, and was also the first clinically approved HSV vector carrying an extracellular matrix (ECM)-modifying transgene. The ECM is a network of macromolecules surrounding cells, which provides support and regulates cell growth and differentiation, the disruption of which is common in cancer. The naked mole rat (NMR) has a thick ECM and a unique mutation in the hyaluronan synthase 2 (HAS2) gene, which has been linked to the high cancer resistance of the species. To study the effect of this mutation in human cancer, we have developed an attenuated, replication-competent HSV vector expressing the NMR-HAS2 gene. The viral replication, transgene expression and cytotoxic effect of the novel vector was studied in glioma cells. Our results show that an attenuated, replication-competent HSV vector expressing a foreign ECM-modifying transgene, namely HAS2, provides an effective tool to study and combat cancer in humans.

Molecular weight of hyaluronic acid crosslinked into biomaterial scaffolds affects angiogenic potential

While hyaluronic acid (HA)-based hydrogels have been used clinically for decades, the mechanisms by which HA exerts molecular weight-dependent bioactivity and how chemical modification and crosslinking may affect molecular weight-dependent bioactivity remain poorly understood. This knowledge gap presents a significant barrier to designing HA hydrogels with predictable bioactivities. As HA has been widely reported to have molecular weight-dependent effects on endothelial cells (ECs), we investigated how the molecular weight of HA in either soluble or crosslinked forms affects angiogenesis and interrogated CD44 clustering on the surface of endothelial cells as a candidate mechanism for these affects. Using soluble HA, our results show high molecular weight (HMW) HA, but not low molecular weight (LMW) HA, increased viability and tube formation in cultured human cerebral microvascular ECs (HCMVECs). No size of HA affected proliferation. When HCMVECs were cultured with crosslinked HA of varying molecular weights in the form of HA-based microporous annealed particle scaffold (HMAPS), the cell response was comparable to when cultured with soluble HA. Similarly, when implanted subcutaneously, HMAPS with HMW HA were more vascularized than those with LMW HA. We also show that antibody-mediated CD44 clustering resulted in HCMVECs with increased viability and tube-like structure formation in a manner comparable to exposure to HMW HA, suggesting that HMW acts through CD44 clustering. STATEMENT OF SIGNIFICANCE: Biomaterials based on hyaluronic acid (HA), a bioactive extracellular matrix polysaccharide, have been used in clinical products for several years. Despite the knowledge that HA molecular weight heavily influences its bioactivity, molecular weight has been largely ignored in the development of HA-based biomaterials. Given the high viscosity of high molecular weight HA typically found in native tissues, lower molecular weight polysaccharides have been used most commonly for biomaterial fabrication. By comparing the ability of injectable, microporous annealed particle scaffolds (MAPS) fabricated from variably sized HA to promote angiogenesis, this study demonstrates that MAPS with high molecular weight HA better support vascularization, likely through an unique ability to induce clustering of CD44 receptors on endothelial cells.

Polysaccharide hydrogel platforms as suitable carriers of liposomes and extracellular vesicles for dermal applications

Lipid-based nanocarriers have been extensively investigated for their application in drug delivery. Particularly, liposomes are now clinically established for treating various diseases such as fungal infections. In contrast, extracellular vesicles (EVs) - small cell-derived nanoparticles involved in cellular communication - have just recently sparked interest as drug carriers but their development is still at the preclinical level. To drive this development further, the methods and technologies exploited in the context of liposome research should be applied in the domain of EVs to facilitate and accelerate their clinical translation. One of the crucial steps for EV-based therapeutics is designing them as proper dosage forms for specific applications. This review offers a comprehensive overview of state-of-the-art polysaccharide-based hydrogel platforms designed for artificial and natural vesicles with application in drug delivery to the skin. We discuss their various physicochemical and biological properties and try to create a sound basis for the optimization of EV-embedded hydrogels as versatile therapeutic avenues.

Regulation of tumor immunity and immunotherapy by the tumor collagen extracellular matrix

It has been known for decades that the tumor extracellular matrix (ECM) is dysfunctional leading to loss of tissue architecture and promotion of tumor growth. The altered ECM and tumor fibrogenesis leads to tissue stiffness that act as a physical barrier to immune cell infiltration into the tumor microenvironment (TME). It is becoming increasingly clear that the ECM plays important roles in tumor immune responses. A growing body of data now indicates that ECM components also play a more active role in immune regulation when dysregulated ECM components act as ligands to interact with receptors on immune cells to inhibit immune cell subpopulations in the TME. In addition, immunotherapies such as checkpoint inhibitors that are approved to treat cancer are often hindered by ECM changes. In this review we highlight the ways by which ECM alterations affect and regulate immunity in cancer. More specifically, how collagens and major ECM components, suppress immunity in the complex TME. Finally, we will review how our increased understanding of immune and immunotherapy regulation by the ECM is leading towards novel disruptive strategies to overcome immune suppression.

Ultrasensitive dose-response for asbestos cancer risk implied by new inflammation-mutation model

Alterations in complex cellular phenotype each typically involve multistep activation of an ultrasensitive molecular switch (e.g., to adaptively initiate an apoptosis, inflammasome, Nrf2-ARE anti-oxidant, or heat-shock activation pathway) that triggers expression of a suite of target genes while efficiently limiting false-positive switching from a baseline state. Such switches exhibit nonlinear signal-activation relationships. In contrast, a linear no-threshold (LNT) dose-response relationship is expected for damage that accumulates in proportion to dose, as hypothesized for increased risk of cancer in relation to genotoxic dose according to the multistage somatic mutation/clonal-expansion theory of cancer, e.g., as represented in the Moolgavkar-Venzon-Knudsen (MVK) cancer model by a doubly stochastic nonhomogeneous Poisson process. Mesothelioma and lung cancer induced by exposure to carcinogenic (e.g., certain asbestos) fibers in humans and experimental animals are thought to involve modes of action driven by mutations, cytotoxicity-associated inflammation, or both, rendering ambiguous expectations concerning the nature of model-implied shape of the low-dose response for above-background increase in risk of incurring these endpoints. A recent Inflammation Somatic Mutation (ISM) theory of cancer posits instead that tissue-damage-associated inflammation that epigenetically recruits, activates and orchestrates stem cells to engage in tissue repair does not merely promote cancer, but rather is a requisite co-initiator (acting together with as few as two somatic mutations) of the most efficient pathway to any type of cancer in any reparable tissue (Dose-Response 2019; 17(2):1-12). This theory is reviewed, implications of this theory are discussed in relation to mesothelioma and lung cancer associated with chronic asbestos inhalation, one of the two types of ISM-required mutations is here hypothesized to block or impede inflammation resolution (e.g., by doing so for GPCR-mediated signal transduction by one or more endogenous autacoid specialized pro-resolving mediators or SPMs), and supporting evidence for this hypothesis is discussed.

Don't go breakin' my heart: cardioprotective alterations to the mechanical and structural properties of reperfused myocardium during post-infarction inflammation

Myocardial infarctions (MIs) kickstart an intense inflammatory response resulting in extracellular matrix (ECM) degradation, wall thinning, and chamber dilation that leaves the heart susceptible to rupture. Reperfusion therapy is one of the most effective strategies for limiting adverse effects of MIs, but is a challenge to administer in a timely manner. Late reperfusion therapy (LRT; 3 + hours post-MI) does not limit infarct size, but does reduce incidences of post-MI rupture and improves long-term patient outcomes. Foundational studies employing LRT in the mid-twentieth century revealed beneficial reductions in infarct expansion, aneurysm formation, and left ventricle dysfunction. The mechanism by which LRT acts, however, is undefined. Structural analyses, relying largely on one-dimensional estimates of ECM composition, have found few differences in collagen content between LRT and permanently occluded animal models when using homogeneous samples from infarct cores. Uniaxial testing, on the other hand, revealed slight reductions in stiffness early in inflammation, followed soon after by an enhanced resistance to failure for cases of LRT. The use of one-dimensional estimates of ECM organization and gross mechanical function have resulted in a poor understanding of the infarct's spatially variable mechanical and structural anisotropy. To resolve these gaps in literature, future work employing full-field mechanical, structural, and cellular analyses is needed to better define the spatiotemporal post-MI alterations occurring during the inflammatory phase of healing and how they are impacted following reperfusion therapy. In turn, these studies may reveal how LRT affects the likelihood of rupture and inspire novel approaches to guide scar formation.

Hyaluronan breakdown by snake venom hyaluronidases: From toxins delivery to immunopathology

Snake venom enzymes have a broad range of molecular targets in plasma, tissues, and cells, among which hyaluronan (HA) is outstanding. HA is encountered in the extracellular matrix of diverse tissues and in the bloodstream, and its different chemical configurations dictate the diverse morphophysiological processes in which it participates. Hyaluronidases are highlighted among the enzymes involved in HA metabolism. This enzyme has been detected along the phylogenetic tree, suggesting that hyaluronidases exert multiple biological effects on different organisms. Hyaluronidases have been described in tissues, blood and snake venoms. Snake venom hyaluronidases (SVHYA) contribute to tissue destruction in envenomations and are called spreading factors since their action potentiates venom toxin delivery. Interestingly, SVHYA are clustered in Enzyme Class 3.2.1.35 together with mammalian hyaluronidases (HYAL). Both HYAL and SVHYA of Class 3.2.1.35 act upon HA, generating low molecular weight HA fragments (LMW-HA). LMW-HA generated by HYAL becomes a damage-associated molecular pattern that is recognized by Toll-like receptors 2 and 4, triggering cell signaling cascades culminating in innate and adaptive immune responses that are characterized by lipid mediator generation, interleukin production, chemokine upregulation, dendritic cell activation and T cell proliferation. In this review, aspects of the structures and functions of HA and hyaluronidases in both snake venoms and mammals are presented, and their activities are compared. In addition, the potential immunopathological consequences of HA degradation products generated after snakebite envenoming and their use as adjuvant to enhance venom toxin immunogenicity for antivenom production as well as envenomation prognostic biomarker are also discussed.

Hyaluronan Receptors as Mediators and Modulators of the Tumor Microenvironment

The tumor microenvironment (TME) is a dynamic and complex matter shaped by heterogenous cancer and cancer-associated cells present at the tumor site. Hyaluronan (HA) is a major TME component that plays pro-tumorigenic and carcinogenic functions. These functions are mediated by different hyaladherins expressed by cancer and tumor-associated cells triggering downstream signaling pathways that determine cell fate and contribute to TME progression toward a carcinogenic state. Here, the interaction of HA is reviewed with several cell-surface hyaladherins-CD44, RHAMM, TLR2 and 4, LYVE-1, HARE, and layilin. The signaling pathways activated by these interactions and the respective response of different cell populations within the TME, and the modulation of the TME, are discussed. Potential cancer therapies via targeting these interactions are also briefly discussed.

Hyaluronan in the pathogenesis of acute and post-acute COVID-19 infection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) recently emerged as the cause of a global pandemic. Infection with SARS-CoV-2 can result in COVID-19 with both acute and chronic disease manifestations that continue to impact many patients long after the resolution of viral replication. There is therefore great interest in understanding the host factors that contribute to COVID-19 pathogenesis. In this review, we address the role of hyaluronan (HA), an extracellular matrix polymer with roles in inflammation and cellular metabolism, in COVID-19 and critically evaluate the hypothesis that HA promotes COVID-19 pathogenesis. We first provide a brief overview of COVID-19 infection. Then we briefly summarize the known roles of HA in airway inflammation and immunity. We then address what is known about HA and the pathogenesis of COVID-19 acute respiratory distress syndrome (COVID-19 ARDS). Next, we examine potential roles for HA in post-acute SARS-CoV-2 infection (PASC), also known as "long COVID" as well as in COVID-associated fibrosis. Finally, we discuss the potential therapeutics that target HA as a means to treat COVID-19, including the repurposed drug hymecromone (4-methylumbelliferone). We conclude that HA is a promising potential therapeutic target for the treatment of COVID-19.

Inflammation and Heart Failure: Searching for the Enemy-Reaching the Entelechy

The pivotal role of inflammation in the pathophysiology of heart-failure (HF) development and progression has long been recognized. High blood levels of pro-inflammatory and inflammatory markers are present and associated with adverse outcomes in patients with HF. In addition, there seems to be an interrelation between inflammation and neurohormonal activation, the cornerstone of HF pathophysiology and management. However, clinical trials involving anti-inflammatory agents have shown inconclusive or even contradictory results in improving HF outcomes. In the present review, we try to shed some light on the reciprocal relationship between inflammation and HF in an attempt to identify the central regulating factors, such as inflammatory cells and soluble mediators and the related inflammatory pathways as potential therapeutic targets.

Absorption, metabolism, and functions of hyaluronic acid and its therapeutic prospects in combination with microorganisms: A review

Hyaluronic acid (HA) is key to the stability of the internal environment of tissues. HA content in tissues gradually decreases with age, causing age-related health problems. Exogenous HA supplements are used to prevent or treat these problems including skin dryness and wrinkles, intestinal imbalance, xerophthalmia, and arthritis after absorption. Moreover, some probiotics are able to promote endogenous HA synthesis and alleviate symptoms caused by HA loss, thus introducing potential preventative or therapeutic applications of HA and probiotics. Here, we review the oral absorption, metabolism, and biological function of HA as well as the potential role of probiotics and HA in increasing the efficacy of HA supplements.

Acute Inflammation in Tissue Healing

There are well-established links between acute inflammation and successful tissue repair across evolution. Innate immune reactions contribute significantly to pathogen clearance and activation of subsequent reparative events. A network of molecular and cellular regulators supports antimicrobial and tissue repair functions throughout the healing process. A delicate balance must be achieved between protection and the potential for collateral tissue damage associated with overt inflammation. In this review, we summarize the contributions of key cellular and molecular components to the acute inflammatory process and the effective and timely transition toward activation of tissue repair mechanisms. We further discuss how the disruption of inflammatory responses ultimately results in chronic non-healing injuries.

CEMIP as a prognostic biomarker for cancers: a meta- and bioinformatic analysis

OBJECTIVE

Cell migration-inducing and hyaluronan-binding protein (CEMIP) is overexpressed in several cancers and is related to prognosis in cancer patients. Here, we conducted a meta-analysis to explore the prognostic effects of CEMIP in cancer patients.

METHODS

Relevant published studies were systematically searched in four databases. The role of CEMIP was evaluated using pooled hazard ratios (HRs), odd ratios (ORs), and 95% confidence intervals (95% CIs). The Cancer Genome Atlas (TCGA) was used to investigate the prognostic value of CEMIP in various cancers.

RESULTS

11 literatures with 1355 patients were included in this meta-analysis. The results showed that overexpression of CEMIP was significantly associated with poor OS (HR = 3.03; 95% CI: 2.00-4.59; p < 0.001), DFS (HR = 3.38; 95% CI: 2.41-4.74; p < 0.001). Elevated CEMIP expression is associated with advanced clinical stage, lymph node metastasis, and poor histological grade. In addition, TCGA datasets were used to verify that CEMIP was found highly expressed in multiple cancers and was associated with poorer survival.

CONCLUSION

The results demonstrated that CEMIP could be a novel prognostic biomarker for cancer patients. However, because the included studies mainly focused on Asian populations, further research is needed to verify its applicability.

Sterile abscess due to hyaluronic acid: A new diagnosis and a proposal for treatment-A series of eight cases

BACKGROUND

In recent years, fillers procedures with hyaluronic acid (HA) have grown significantly. Despite HA relative safety, the number of cases of complications after injections has grown, and in many of which, we are not aware of or have little control over.

AIMS

In this article, the authors describe a new adverse reaction after filling with HA injection, the sterile abscess.

PATIENTS/METHODS

We present eight patients with similar clinical, laboratory, and ultrasound characteristics for sterile abscess and report a new therapeutic modality for it.

RESULTS

All cases were treated with "Munhoz-Cavallieri Lavage Protocol" procedure with complete resolution.

CONCLUSIONS

"Munhoz-Cavallieri Lavage Protocol" serves as a guideline in diagnosis and management of sterile abscess.

Vaginal microbiome: considerations for reproductive health

The microbial communities are an indispensable part of the human defense system and coexist with humans as symbionts, contributing to the metabolic functions and immune defense against pathogens. An ecologically stable vaginal microbiota is dominated by Lactobacillus species, which plays an important role in the prevention of genital infections by controlling the vaginal pH, reducing glycogen to lactic acid, and stimulating bacteriocins and hydrogen peroxide. In contrast, an abnormal vaginal microbial composition is associated with an increased risk of bacterial vaginosis, trichomoniasis, sexually transmitted diseases, preterm labor and other birth defects. This microbial diversity is affected by race, ethnicity, pregnancy, hormonal changes, sexual activities, hygiene practices and other conditions. In the present review, we discuss the changes in the microbial community of the vaginal region at different stages of a female's life cycle and its influence on her reproductive health and pathological conditions.

Deregulated hyaluronan metabolism in the tumor microenvironment drives cancer inflammation and tumor-associated immune suppression

Hyaluronan (HA) is known to be a prominent component of the extracellular matrix in tumors, and many solid cancers are characterized by aberrant HA metabolism resulting in increased production in tumor tissue. HA has been implicated in regulating a variety of cellular functions in tumor cells and tumor-associated stromal cells, suggesting that altered HA metabolism can influence tumor growth and malignancy at multiple levels. Importantly, increased HA production in cancer is associated with enhanced HA degradation due to high levels of expression and activity of hyaluronidases (Hyal). Understanding the complex molecular and cellular mechanisms involved in abnormal HA metabolism and catabolism in solid cancers could have important implications for the design of future cancer therapeutic approaches. It appears that extensive crosstalk between immune cells and HA-enriched stroma contributes to tumor growth and progression in several ways. Specifically, the interaction of tumor-recruited Hyal2-expressing myeloid-derived suppressor cells (MDSCs) of bone marrow origin with HA-producing cancer-associated fibroblasts and epithelial tumor cells results in enhanced HA degradation and accumulation of small pro-inflammatory HA fragments, which further drives cancer-related inflammation. In addition, hyaluronan-enriched stroma supports the transition of tumor-recruited Hyal2⁺MDSCs to the PD-L1⁺ tumor-associated macrophages leading to the formation of an immunosuppressive and tolerogenic tumor microenvironment. In this review, we aim to discuss the contribution of tumor-associated HA to cancer inflammation, angiogenesis, and tumor-associated immune suppression. We also highlight the recent findings related to the enhanced HA degradation in the tumor microenvironment.

Biochemical, biophysical, and immunological characterization of respiratory secretions in severe SARS-CoV-2 infections

Thick, viscous respiratory secretions are a major pathogenic feature of COVID-19, but the composition and physical properties of these secretions are poorly understood. We characterized the composition and rheological properties (i.e., resistance to flow) of respiratory secretions collected from intubated COVID-19 patients. We found the percentages of solids and protein content were greatly elevated in COVID-19 compared with heathy control samples and closely resembled levels seen in cystic fibrosis, a genetic disease known for thick, tenacious respiratory secretions. DNA and hyaluronan (HA) were major components of respiratory secretions in COVID-19 and were likewise abundant in cadaveric lung tissues from these patients. COVID-19 secretions exhibited heterogeneous rheological behaviors, with thicker samples showing increased sensitivity to DNase and hyaluronidase treatment. In histologic sections from these same patients, we observed increased accumulation of HA and the hyaladherin versican but reduced tumor necrosis factor-stimulated gene-6 staining, consistent with the inflammatory nature of these secretions. Finally, we observed diminished type I interferon and enhanced inflammatory cytokines in these secretions. Overall, our studies indicated that increases in HA and DNA in COVID-19 respiratory secretion samples correlated with enhanced inflammatory burden and suggested that DNA and HA may be viable therapeutic targets in COVID-19 infection.

Meta-Analysis of Two Human RNA-seq Datasets to Determine Periodontitis Diagnostic Biomarkers and Drug Target Candidates

Periodontitis is a chronic inflammatory oral disease that affects approximately 42% of adults 30 years of age or older in the United States. In response to microbial dysbiosis within the periodontal pockets surrounding teeth, the host immune system generates an inflammatory environment in which soft tissue and alveolar bone destruction occur. The objective of this study was to identify diagnostic biomarkers and the mechanistic drivers of inflammation in periodontitis to identify drugs that may be repurposed to treat chronic inflammation. A meta-analysis comprised of two independent RNA-seq datasets was performed. RNA-seq analysis, signal pathway impact analysis, protein-protein interaction analysis, and drug target analysis were performed to identify the critical pathways and key players that initiate inflammation in periodontitis as well as to predict potential drug targets. Seventy-eight differentially expressed genes, 10 significantly impacted signaling pathways, and 10 hub proteins in periodontal gingival tissue were identified. The top 10 drugs that may be repurposed for treating periodontitis were then predicted from the gene expression and pathway data. The efficacy of these drugs in treating periodontitis has yet to be investigated. However, this analysis indicates that these drugs may serve as potential therapeutics to treat inflammation in gingival tissue affected by periodontitis.

Biochemical, Biophysical, and Immunological Characterization of Respiratory Secretions in Severe SARS-CoV-2 (COVID-19) Infections.. [PMID: 35411348 PMCID: PMC8996635 DOI: 10.1101/2022.03.28.22272848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Thick, viscous respiratory secretions are a major pathogenic feature of COVID-19 disease, but the composition and physical properties of these secretions are poorly understood. We characterized the composition and rheological properties (i.e. resistance to flow) of respiratory secretions collected from intubated COVID-19 patients. We find the percent solids and protein content are greatly elevated in COVID-19 compared to heathy control samples and closely resemble levels seen in cystic fibrosis, a genetic disease known for thick, tenacious respiratory secretions. DNA and hyaluronan (HA) are major components of respiratory secretions in COVID-19 and are likewise abundant in cadaveric lung tissues from these patients. COVID-19 secretions exhibit heterogeneous rheological behaviors with thicker samples showing increased sensitivity to DNase and hyaluronidase treatment. In histologic sections from these same patients, we observe increased accumulation of HA and the hyaladherin versican but reduced tumor necrosis factor–stimulated gene-6 (TSG6) staining, consistent with the inflammatory nature of these secretions. Finally, we observed diminished type I interferon and enhanced inflammatory cytokines in these secretions. Overall, our studies indicate that increases in HA and DNA in COVID-19 respiratory secretion samples correlate with enhanced inflammatory burden and suggest that DNA and HA may be viable therapeutic targets in COVID-19 infection.

Molecular Insights Into The Interaction Between Human Nicotinamide Phosphoribosyltransferase and Toll-Like Receptor 4

The secreted form of the enzyme nicotinamide phosphoribosyltransferase (NAMPT), which catalyzes a key reaction in intracellular NAD biosynthesis, acts as a damage-associated molecular pattern triggering Toll-like receptor 4 (TLR4)-mediated inflammatory responses. However, the precise mechanism of interaction is unclear. Using an integrated approach combining bioinformatics and functional and structural analyses, we investigated the interaction between NAMPT and TLR4 at the molecular level. Starting from previous evidence that the bacterial ortholog of NAMPT cannot elicit the inflammatory response, despite a high degree of structural conservation, two positively charged areas unique to the human enzyme (the α1-α2 and β1-β2 loops) were identified as likely candidates for TLR4 binding. However, alanine substitution of the positively charged residues within these loops did not affect either the oligomeric state or the catalytic efficiency of the enzyme. The kinetics of the binding of wildtype and mutated NAMPT to biosensor-tethered TLR4 was analyzed. We found that mutations in the α1-α2 loop strongly decreased the association rate, increasing the K_D value from 18 nM, as determined for the wildtype, to 1.3 μM. In addition, mutations in the β1-β2 loop or its deletion increased the dissociation rate, yielding K_D values of 0.63 and 0.22 μM, respectively. Mutations also impaired the ability of NAMPT to trigger the NF-κB inflammatory signaling pathway in human cultured macrophages. Finally, the involvement of the two loops in receptor binding was supported by NAMPT-TLR4 docking simulations. This study paves the way for future development of compounds that selectively target eNAMPT/TLR4 signaling in inflammatory disorders.

Tandem mass tag-based serum proteomic profiling revealed diabetic foot ulcer pathogenesis and potential therapeutic targets

Diabetic foot ulcer (DFU), one of the most serious complications of diabetes mellitus, is associated with a high amputation rate and decreased life quality. The impact of blood serum proteins on the occurrence and development of DFU has attracted a lot of interest. In this study, we aimed to define and compare the serum proteome of patients with DFU and healthy control (HC) to provide new insights into DFU pathogenesis. DFU patients and age- and sex-matched HCs were enrolled in this study (n = 54). We screened alterations in blood serum proteins from DFU patients and HC using a tandem mass tag (TMT) method based on liquid chromatography-mass spectrometry (LC-MS/MS) quantitative proteomics, and the differentially expressed proteins (DEPs) were further validated by parallel reaction monitoring (PRM) and enzyme-linked immunosorbent assay (ELISA). A total of 173 DEPs (100 up-regulated and 73 down-regulated) were identified between the DFU and HC groups (P < 0.05). Proteomic and bioinformatics analyses indicated that the proteins in the DFU group were mainly related to extracellular matrix (ECM)-receptor interaction and complement and coagulation cascades. The up-regulated DEPs were further verified by PRM and ELISA. LRG1, CD5L, CRP, IGHA1, and LBP were proved upregulated in DFU and these proteins are mainly related to immune response and complement activation. Our findings help to provide a more comprehensive understanding of the pathogenesis of DFU and new insight into potential therapeutic targets.

RNA metabolism and links to inflammatory regulation and disease

Inflammation is vital to protect the host against foreign organism invasion and cellular damage. It requires tight and concise gene expression for regulation of pro- and anti-inflammatory gene expression in immune cells. Dysregulated immune responses caused by gene mutations and errors in post-transcriptional regulation can lead to chronic inflammatory diseases and cancer. The mechanisms underlying post-transcriptional gene expression regulation include mRNA splicing, mRNA export, mRNA localisation, mRNA stability, RNA/protein interaction, and post-translational events such as protein stability and modification. The majority of studies to date have focused on transcriptional control pathways. However, post-transcriptional regulation of mRNA in eukaryotes is equally important and related information is lacking. In this review, we will focus on the mechanisms involved in the pre-mRNA splicing events, mRNA surveillance, RNA degradation pathways, disorders or symptoms caused by mutations or errors in post-transcriptional regulation during innate immunity especially toll-like receptor mediated pathways.

Matrix Metalloproteinases Shape the Tumor Microenvironment in Cancer Progression

Cancer progression with uncontrolled tumor growth, local invasion, and metastasis depends largely on the proteolytic activity of numerous matrix metalloproteinases (MMPs), which affect tissue integrity, immune cell recruitment, and tissue turnover by degrading extracellular matrix (ECM) components and by releasing matrikines, cell surface-bound cytokines, growth factors, or their receptors. Among the MMPs, MMP-14 is the driving force behind extracellular matrix and tissue destruction during cancer invasion and metastasis. MMP-14 also influences both intercellular as well as cell-matrix communication by regulating the activity of many plasma membrane-anchored and extracellular proteins. Cancer cells and other cells of the tumor stroma, embedded in a common extracellular matrix, interact with their matrix by means of various adhesive structures, of which particularly invadopodia are capable to remodel the matrix through spatially and temporally finely tuned proteolysis. As a deeper understanding of the underlying functional mechanisms is beneficial for the development of new prognostic and predictive markers and for targeted therapies, this review examined the current knowledge of the interplay of the various MMPs in the cancer context on the protein, subcellular, and cellular level with a focus on MMP14.

Skin inflammation activates intestinal stromal fibroblasts and promotes colitis

Inflammatory disorders of the skin are frequently associated with inflammatory bowel diseases (IBDs). To explore mechanisms by which these organs communicate, we performed single-cell RNA-Seq analysis on fibroblasts from humans and mice with IBD. This analysis revealed that intestinal inflammation promoted differentiation of a subset of intestinal stromal fibroblasts into preadipocytes with innate antimicrobial host defense activity. Furthermore, this process of reactive adipogenesis was exacerbated if mouse skin was inflamed as a result of skin wounding or infection. Since hyaluronan (HA) catabolism is activated during skin injury and fibroblast-to-adipocyte differentiation is dependent on HA, we tested the hypothesis that HA fragments could alter colon fibroblast function by targeted expression of human hyaluronidase-1 in basal keratinocytes from mouse skin. Hyaluronidase expression in the skin activated intestinal stromal fibroblasts, altered the fecal microbiome, and promoted excessive reactive adipogenesis and increased inflammation in the colon after challenge with dextran sodium sulfate. The response to digested HA was dependent on expression of TLR4 by preadipocytes. Collectively, these results suggest that the association between skin inflammation and IBD may be due to recognition by mesenchymal fibroblasts in the colon of HA released during inflammation of the skin.

Leishmania Promastigotes Enhance Neutrophil Recruitment through the Production of CXCL8 by Endothelial Cells

Endothelial cells represent one of the first cell types encountered by Leishmania promastigotes when inoculated into the skin of the human hosts by the bite of phlebotomine sand flies. However, little is known on their role in the early recruitment of phagocytic cells and in the establishment of the infection. Initially, neutrophils, rapidly recruited to the site of promastigotes deposition, phagocytize Leishmania promastigotes, which elude the killing mechanisms of the host cells, survive, and infect other phagocytic cells. Here, we show that Leishmania promastigotes co-incubated with HMEC-1, a microvascular endothelial cell line, exhibited significant morphological changes and loss of infectivity. Moreover, promastigotes of different Leishmania species stimulated the production of CXCL8 by HMEC-1 in a dose- and TLR4-dependent manner. Interestingly, we observed that the conditioned media from Leishmania-stimulated HMEC-1 cells attracted leukocytes, mostly neutrophils, after 2 h of incubation. After 24 h, a higher percentage of monocytes was detected in conditioned media of unstimulated HMEC-1 cells, whereas neutrophils still predominated in conditioned medium from Leishmania-stimulated cells. The same supernatants did not contain CCL5, a chemokine recruiting T cells and monocytes. On the contrary, inhibition of the production of CCL5 induced by TNF-α was seen. These data indicate that the interaction of Leishmania promastigotes with endothelial cells leads to the production of chemokines and the recruitment of neutrophils, which contribute to the establishment of Leishmania infection.

Toll-like receptor 3 is an endogenous sensor of cell death and a potential target for induction of long-term cardiac transplant survival

Inflammation posttransplant is directly linked to cell death programs including apoptosis and necrosis. Cell death leads to the release of cellular contents which can promote inflammation. Targeting of these pathways should be an effective strategy to prevent transplant rejection. Toll-like receptor 3 (TLR3) is emerging as a major endogenous sensor of inflammation. In this study, we assessed the role of TLR3 on cell death and transplant rejection. We showed that TLR3 is highly expressed on mouse microvascular endothelial cell (ECs) and the endothelium of cardiac grafts. We demonstrated that TLR3 interacting with dsRNA or self-RNA triggered apoptosis and necroptosis in ECs. Interestingly, TLR3-induced necroptosis led mitochondrial damage. Inhibition of the mitochondrial membrane permeability molecule Cyclophilin D prevented necroptosis in ECs. In vivo, endothelium damage and activities of caspase-3 and mixed lineage kinase domain-like protein were inhibited in TLR3^-/- cardiac grafts compared with C57BL/6 grafts posttransplant (n = 5, p < .001). Importantly, TLR3^-/- cardiac grafts had prolonged survival in allogeneic BALB/c mice (mean survival = 121 ± 67 vs. 31 ± 6 days of C57BL/6 grafts, n = 7, p = .002). In summary, our study suggests that TLR3 is an important cell death inducer in ECs and cardiac grafts and thus a potential therapeutic target in preventing cardiac transplant rejection.

Plaque erosion and acute coronary syndromes: phenotype, molecular characteristics and future directions

Although acute coronary syndromes (ACS) remain one of the leading causes of death, the clinical presentation has changed over the past three decades with a decline in the incidence of ST-segment elevation myocardial infarction (STEMI) and an increase in non-STEMI. This epidemiological shift is at least partially explained by changes in plaque biology as a result of the widespread use of statins. Historically, atherosclerotic plaque rupture of the fibrous cap was thought to be the main culprit in ACS. However, plaque erosion with an intact fibrous cap is now responsible for about one third of ACS and up to two thirds of non-STEMI. Two major research approaches have enabled a better understanding of plaque erosion. First, advanced intravascular imaging has provided opportunities for an 'optical biopsy' and extensive phenotyping of coronary plaques in living patients. Second, basic science experiments have shed light on the unique molecular characteristics of plaque erosion. At present, patients with ACS are still uniformly treated with coronary stents irrespective of the underlying pathobiology. However, pilot studies indicate that patients with plaque erosion might be treated conservatively without coronary stenting. In this Review, we discuss the patient phenotype and the molecular characteristics in atherosclerotic plaque erosion and provide our vision for a potential major shift in the management of patients with plaque erosion.

Modulation of hyaluronan signaling as a therapeutic target in human disease

The extracellular matrix is an active participant, modulator and mediator of the cell, tissue, organ and organismal response to injury. Recent research has highlighted the role of hyaluronan, an abundant glycosaminoglycan constituent of the extracellular matrix, in many fundamental biological processes underpinning homeostasis and disease development. From this basis, emerging studies have demonstrated the therapeutic potential of strategies which target hyaluronan synthesis, biology and signaling, with significant promise as therapeutics for a variety of inflammatory and immune diseases. This review summarizes the state of the art in this field and discusses challenges and opportunities in what could emerge as a new class of therapeutic agents, that we term "matrix biologics".

Bacterial and Host Determinants of Group B Streptococcal Vaginal Colonization and Ascending Infection in Pregnancy

Group B streptococcus (GBS) is a gram-positive bacteria that asymptomatically colonizes the vaginal tract. However, during pregnancy maternal GBS colonization greatly predisposes the mother and baby to a wide range of adverse outcomes, including preterm birth (PTB), stillbirth, and neonatal infection. Although many mechanisms involved in GBS pathogenesis are partially elucidated, there is currently no approved GBS vaccine. The development of a safe and effective vaccine that can be administered during or prior to pregnancy remains a principal objective in the field, because current antibiotic-based therapeutic strategies do not eliminate all cases of invasive GBS infections. Herein, we review our understanding of GBS disease pathogenesis at the maternal-fetal interface with a focus on the bacterial virulence factors and host defenses that modulate the outcome of infection. We follow GBS along its path from an asymptomatic colonizer of the vagina to an invasive pathogen at the maternal-fetal interface, noting factors critical for vaginal colonization, ascending infection, and vertical transmission to the fetus. Finally, at each stage of infection we emphasize important host-pathogen interactions, which, if targeted therapeutically, may help to reduce the global burden of GBS.

COVID-19 generates hyaluronan fragments that directly induce endothelial barrier dysfunction

Vascular injury has emerged as a complication contributing to morbidity in coronavirus disease 2019 (COVID-19). The glycosaminoglycan hyaluronan (HA) is a major component of the glycocalyx, a protective layer of glycoconjugates that lines the vascular lumen and regulates key endothelial cell functions. During critical illness, as in the case of sepsis, enzymes degrade the glycocalyx, releasing fragments with pathologic activities into circulation and thereby exacerbating disease. Here, we analyzed levels of circulating glycosaminoglycans in 46 patients with COVID-19 ranging from moderate to severe clinical severity and measured activities of corresponding degradative enzymes. This report provides evidence that the glycocalyx becomes significantly damaged in patients with COVID-19 and corresponds with severity of disease. Circulating HA fragments and hyaluronidase, 2 signatures of glycocalyx injury, strongly associate with sequential organ failure assessment scores and with increased inflammatory cytokine levels in patients with COVID-19. Pulmonary microvascular endothelial cells exposed to COVID-19 milieu show dysregulated HA biosynthesis and degradation, leading to production of pathological HA fragments that are released into circulation. Finally, we show that HA fragments present at high levels in COVID-19 patient plasma can directly induce endothelial barrier dysfunction in a ROCK- and CD44-dependent manner, indicating a role for HA in the vascular pathology of COVID-19.

Hyaluronan and Its Receptors: Key Mediators of Immune Cell Entry and Trafficking in the Lymphatic System

Entry to the afferent lymphatics marks the first committed step for immune cell migration from tissues to draining lymph nodes both for the generation of immune responses and for timely resolution of tissue inflammation. This critical process occurs primarily at specialised discontinuous junctions in initial lymphatic capillaries, directed by chemokines released from lymphatic endothelium and orchestrated by adhesion between lymphatic receptors and their immune cell ligands. Prominent amongst the latter is the large glycosaminoglycan hyaluronan (HA) that can form a bulky glycocalyx on the surface of certain tissue-migrating leucocytes and whose engagement with its key lymphatic receptor LYVE-1 mediates docking and entry of dendritic cells to afferent lymphatics. Here we outline the latest insights into the molecular mechanisms by which the HA glycocalyx together with LYVE-1 and the related leucocyte receptor CD44 co-operate in immune cell entry, and how the process is facilitated by the unusual character of LYVE-1 • HA-binding interactions. In addition, we describe how pro-inflammatory breakdown products of HA may also contribute to lymphatic entry by transducing signals through LYVE-1 for lymphangiogenesis and increased junctional permeability. Lastly, we outline some future perspectives and highlight the LYVE-1 • HA axis as a potential target for immunotherapy.

Aggravation of hepatic ischemia‑reperfusion injury with increased inflammatory cell infiltration is associated with the TGF‑β/Smad3 signaling pathway

Ischemia‑reperfusion (IR) injury is a major challenge influencing the outcomes of hepatic transplantation. Transforming growth factor‑β (TGF‑β) and its downstream gene, SMAD family member 3 (Smad3), have been implicated in the pathogenesis of chronic hepatic injuries, such as hepatic fibrosis. Thus, the present study aimed to investigate the role of the TGF‑β/Smad3 signaling pathway on hepatic injury induced by IR in vivo. In total, 20 129S2/SvPasCrl wild‑type (WT) mice were randomized into two groups; 10 mice underwent IR injury surgery and 10 mice were sham‑operated. Histopathological changes in liver tissues and serum levels of alanine aminotransferase (ALT) were examined to confirm hepatic injury caused by IR surgery. The expression levels of TGF‑β1, Smad3 and phosphorylated‑Smad3 (p‑Smad3) were detected via western blotting. Furthermore, a total of five Smad3^‑/‑ 129S2/SvPasCrl mice (Smad3^‑/‑ mice) and 10 Smad3^+/+ littermates received IR surgery, while another five Smad3^‑/‑ mice and 10 Smad3^+/+ littermates received the sham operation. Histopathological changes in liver tissues and serum levels of ALT were then compared between the groups. Furthermore, hepatic apoptosis and inflammatory cell infiltration after IR were evaluated in the liver tissues of Smad3^‑/‑ mice and Smad3^+/+ mice. The results demonstrated that the expression levels of TGF‑β1, Smad3 and p‑Smad3 were elevated in hepatic tissue from WT mice after IR injury. Aggravated hepatic injury, increased apoptosis and enhanced inflammatory cell infiltration induced by hepatic IR injury were observed in the Smad3^‑/‑ mice compared with in Smad3^+/+ mice. Collectively, the current findings suggested that activation of the TGF‑β/Smad3 signaling pathway was present alongside the hepatic injury induced by IR. However, the TGF‑β/Smad3 signaling pathway may have an effect on protecting against liver tissue damage caused by IR injury in vivo.

Sexual dimorphism in the nociceptive effects of hyaluronan

ABSTRACT

Intradermal administration of low-molecular-weight hyaluronan (LMWH) in the hind paw induced dose-dependent (0.1, 1, or 10 µg) mechanical hyperalgesia of similar magnitude in male and female rats. However, the duration of LMWH hyperalgesia was greater in females. This sexual dimorphism was eliminated by bilateral ovariectomy and by intrathecal administration of an oligodeoxynucleotide (ODN) antisense to the G-protein-coupled estrogen receptor (GPR30) mRNA in females, indicating estrogen dependence. To assess the receptors at which LMWH acts to induce hyperalgesia, LMWH was administered to groups of male and female rats that had been pretreated with ODN antisense (or mismatch) to the mRNA for 1 of 3 hyaluronan receptors, cluster of differentiation 44 (CD44), toll-like receptor 4, or receptor for hyaluronan-mediated motility (RHAMM). Although LMWH-induced hyperalgesia was attenuated in both male and female rats pretreated with ODN antisense for CD44 and toll-like receptor 4 mRNA, RHAMM antisense pretreatment only attenuated LMWH-induced hyperalgesia in males. Oligodeoxynucleotide antisense for RHAMM, however, attenuated LMWH-induced hyperalgesia in female rats treated with ODN antisense to GPR30, as well as in ovariectomized females. Low-molecular-weight hyaluronan-induced hyperalgesia was significantly attenuated by pretreatment with high-molecular-weight hyaluronan (HMWH) in male, but not in female rats. After gonadectomy or treatment with ODN antisense to GPR30 expression in females, HMWH produced similar attenuation of LMWH-induced hyperalgesia to that seen in males. These experiments identify nociceptors at which LMWH acts to produce mechanical hyperalgesia, establishes estrogen dependence in the role of RHAMM in female rats, and establishes estrogen dependence in the inhibition of LMWH-induced hyperalgesia by HMWH.

Bioactive potential of natural biomaterials: identification, retention and assessment of biological properties

Biomaterials have had an increasingly important role in recent decades, in biomedical device design and the development of tissue engineering solutions for cell delivery, drug delivery, device integration, tissue replacement, and more. There is an increasing trend in tissue engineering to use natural substrates, such as macromolecules native to plants and animals to improve the biocompatibility and biodegradability of delivered materials. At the same time, these materials have favourable mechanical properties and often considered to be biologically inert. More importantly, these macromolecules possess innate functions and properties due to their unique chemical composition and structure, which increase their bioactivity and therapeutic potential in a wide range of applications. While much focus has been on integrating these materials into these devices via a spectrum of cross-linking mechanisms, little attention is drawn to residual bioactivity that is often hampered during isolation, purification, and production processes. Herein, we discuss methods of initial material characterisation to determine innate bioactivity, means of material processing including cross-linking, decellularisation, and purification techniques and finally, a biological assessment of retained bioactivity of a final product. This review aims to address considerations for biomaterials design from natural polymers, through the optimisation and preservation of bioactive components that maximise the inherent bioactive potency of the substrate to promote tissue regeneration.

A guide to the composition and functions of the extracellular matrix

Extracellular matrix (ECM) is a dynamic 3-dimensional network of macromolecules that provides structural support for the cells and tissues. Accumulated knowledge clearly demonstrated over the last decade that ECM plays key regulatory roles since it orchestrates cell signaling, functions, properties and morphology. Extracellularly secreted as well as cell-bound factors are among the major members of the ECM family. Proteins/glycoproteins, such as collagens, elastin, laminins and tenascins, proteoglycans and glycosaminoglycans, hyaluronan, and their cell receptors such as CD44 and integrins, responsible for cell adhesion, comprise a well-organized functional network with significant roles in health and disease. On the other hand, enzymes such as matrix metalloproteinases and specific glycosidases including heparanase and hyaluronidases contribute to matrix remodeling and affect human health. Several cell processes and functions, among them cell proliferation and survival, migration, differentiation, autophagy, angiogenesis, and immunity regulation are affected by certain matrix components. Structural alterations have been also well associated with disease progression. This guide on the composition and functions of the ECM gives a broad overview of the matrisome, the major ECM macromolecules, and their interaction networks within the ECM and with the cell surface, summarizes their main structural features and their roles in tissue organization and cell functions, and emphasizes the importance of specific ECM constituents in disease development and progression as well as the advances in molecular targeting of ECM to design new therapeutic strategies.

Pathological matrix stiffness promotes cardiac fibroblast differentiation through the POU2F1 signaling pathway

Cardiac fibroblast (CF) differentiation into myofibroblasts is a crucial cause of cardiac fibrosis, which increases in the extracellular matrix (ECM) stiffness. The increased stiffness further promotes CF differentiation and fibrosis. However, the molecular mechanism is still unclear. We used bioinformatics analysis to find new candidates that regulate the genes involved in stiffness-induced CF differentiation, and found that there were binding sites for the POU-domain transcription factor, POU2F1 (also known as Oct-1), in the promoters of 50 differentially expressed genes (DEGs) in CFs on the stiffer substrate. Immunofluorescent staining and Western blotting revealed that pathological stiffness upregulated POU2F1 expression and increased CF differentiation on polyacrylamide hydrogel substrates and in mouse myocardial infarction tissue. A chromatin immunoprecipitation assay showed that POU2F1 bound to the promoters of fibrosis repressors IL1R2, CD69, and TGIF2. The expression of these fibrosis repressors was inhibited on pathological substrate stiffness. Knockdown of POU2F1 upregulated these repressors and attenuated CF differentiation on pathological substrate stiffness (35 kPa). Whereas, overexpression of POU2F1 downregulated these repressors and enhanced CF differentiation. In conclusion, pathological stiffness upregulates the transcription factor POU2F1 to promote CF differentiation by inhibiting fibrosis repressors. Our work elucidated the crosstalk between CF differentiation and the ECM and provided a potential target for cardiac fibrosis treatment.

Nonmicrobial Activation of TLRs Controls Intestinal Growth, Wound Repair, and Radioprotection

TLRs, key components of the innate immune system, recognize microbial molecules. However, TLRs also recognize some nonmicrobial molecules. In particular, TLR2 and TLR4 recognize hyaluronic acid, a glycosaminoglycan in the extracellular matrix. In neonatal mice endogenous hyaluronic acid binding to TLR4 drives normal intestinal growth. Hyaluronic acid binding to TLR4 in pericryptal macrophages results in cyclooxygenase2- dependent PGE2 production, which transactivates EGFR in LGR5+ crypt epithelial stem cells leading to increased proliferation. The expanded population of LGR5+ stem cells leads to crypt fission and lengthening of the intestine and colon. Blocking this pathway at any point (TLR4 activation, PGE2 production, EGFR transactivation) results in diminished intestinal and colonic growth. A similar pathway leads to epithelial proliferation in wound repair. The repair phase of dextran sodium sulfate colitis is marked by increased epithelial proliferation. In this model, TLR2 and TLR4 in pericryptal macrophages are activated by microbial products or by host hyaluronic acid, resulting in production of CXCL12, a chemokine. CXCL12 induces the migration of cyclooxygenase2-expressing mesenchymal stem cells from the lamina propria of the upper colonic crypts to a site adjacent to LGR5+ epithelial stem cells. PGE2 released by these mesenchymal stem cells transactivates EGFR in LGR5+ epithelial stem cells leading to increased proliferation. Several TLR2 and TLR4 agonists, including hyaluronic acid, are radioprotective in the intestine through the inhibition of radiation-induced apoptosis in LGR5+ epithelial stem cells. Administration of exogenous TLR2 or TLR4 agonists activates TLR2/TLR4 on pericryptal macrophages inducing CXCL12 production with migration of cyclooxygenase2-expressing mesenchymal stem cells from the lamina propria of the villi to a site adjacent to LGR5+ epithelial stem cells. PGE2 produced by these mesenchymal stem cells, blocks radiation-induced apoptosis in LGR5+ epithelial stem cells by an EGFR mediated pathway.

Changes in the Vaginal Microbiome during the Pregnancy to Postpartum Transition

Substantial changes in the composition of the vaginal microbiome occur following the end of pregnancy. To identify potential drivers of microbiome changes in individual women during the pregnancy to postpartum transition, we evaluated vaginal samples from 48 pregnant women during their first and third trimesters and postpartum. We determined the species composition of vaginal communities and the vaginal fluid levels of compounds involved in mediating changes in host physiology and the immune system at each time point. We used linear mixed-effects models to characterize associations. Consistent with previous reports, but with a larger sample size, a US population, and variations in the dominant bacteria, the vaginal microbiome was found to be more diverse during the postpartum period. There was a lower abundance of Lactobacillus and significantly higher proportions of Streptococcus anginosus and Prevotella bivia. Moreover, we uniquely demonstrated that postpartum vaginal secretions were also altered postpartum. There were elevated levels of hyaluronan and Hsp70 and decreased levels of the D- and L-lactic acid isomers. We posit that these variations are consequences of alterations in the vagina after delivery that profoundly alter the host environment and, thus, lead to changes in the capability of different bacterial species to survive and proliferate.

Hyaluronan Degradation by Cemip Regulates Host Defense against Staphylococcus aureus Skin Infection

Staphylococcus aureus is a major human bacterial pathogen responsible for deep tissue skin infections. Recent observations have suggested that rapid, localized digestion of hyaluronic acid in the extracellular matrix (ECM) of the dermis may influence bacterial invasion and tissue inflammation. In this study we find that cell migration-inducing protein (Cemip) is the major inducible gene responsible for hyaluronan catabolism in mice. Cemip^−/− mice failed to digest hyaluronan and had significantly less evidence of infection after intradermal bacterial challenge by S. aureus. Stabilization of large-molecular-weight hyaluronan enabled increased expression of cathelicidin antimicrobial peptide (Camp) that was due in part to enhanced differentiation of preadipocytes to adipocytes, as seen histologically and by increased expression of Pref1, PPARg, and Adipoq. Cemip^−/− mice challenged with S. aureus also had greater IL-6 expression and neutrophil infiltration. These observations describe a mechanism for hyaluronan in the dermal ECM to regulate tissue inflammation and host antimicrobial defense.

In this paper, Dokoshi et al. describe how the mammalian hyaluronidase Cemip is induced in the dermis during S. aureus infection. Cemip digests hyaluronan in the skin to regulate reactive adipogenesis and subsequent antimicrobial activity and skin inflammation.

Gender Differences in Low-Molecular-Mass-Induced Acute Lung Inflammation in Mice

Gender differences in pulmonary inflammation have been well documented. Although low molecular mass hyaluronan (LMMHA) is known to trigger pulmonary lung inflammation, sex differences in susceptibility to LMMHA are still unknown. In this study, we test the hypothesis that mice may display sex-specific differences after LMMHA administration. After LMMHA administration, male mice have higher neutrophil, cytokine, and chemokine counts compared to that of their female counterparts. Additionally, Ovariectomized (OVX) mice show greater LMMHA-induced inflammation compared to that of mice with intact ovaries. Injections of OVX mice with 17β-estradiol can decrease inflammatory responses in the OVX mice. These results show that ovarian hormones regulate LMMHA induced lung inflammation.

Toll-like receptor 4 (TLR4) antagonists as potential therapeutics for intestinal inflammation

Gastrointestinal inflammation is a hallmark of highly prevalent disorders, including cancer treatment-induced mucositis and ulcerative colitis. These disorders cause debilitating symptoms, have a significant impact on quality of life, and are poorly managed. The activation of toll-like receptor 4 (TLR4) has been proposed to have a major influence on the inflammatory signalling pathways of the intestinal tract. Inhibition of TLR4 has been postulated as an effective way to treat intestinal inflammation. However, there are a limited number of studies looking into the potential of TLR4 antagonism as a therapeutic approach for intestinal inflammation. This review surveyed available literature and reported on the in vitro, ex vivo and in vivo effects of TLR4 antagonism on different models of intestinal inflammation. Of the studies reviewed, evidence suggests that there is indeed potential for TLR4 antagonists to treat inflammation, although only a limited number of studies have investigated treating intestinal inflammation with TLR4 antagonists directly. These results warrant further research into the effect of TLR4 antagonists in the intestinal tract.

Hyaluronan and Its Receptors as Regulatory Molecules of the Endothelial Interface

On the surface of endothelial cells (ECs) lies the glycocalyx, a barrier of polysaccharides that isolates the ECs from the blood. The role of the glycocalyx is dynamic and complex, thanks to not only its structure, but its vast number of components, one being hyaluronan (HA). HA is a critical component of the glycocalyx, having been found to have a wide variety of functions depending on its molecular weight, its modification, and receptor-ligand interactions. As HA and viscous blood are in constant contact, HA can transmit mechanosensory information directly to the cytoskeleton of the ECs. The degradation and synthesis of HA directly alters the permeability of the EC barrier; HA modulation not only alters the physical barrier but also can signal the initiation of other pathways. EC proliferation and angiogenesis are in part regulated by HA fragmentation, HA-dependent receptor binding, and downstream signals. The interaction between the CD44 receptor and HA is a driving force behind leukocyte recruitment, but each class of leukocyte still interacts with HA in unique ways during inflammation. HA regulates a diverse repertoire of EC functions.

Extracellular Matrix in Ischemic Heart Disease, Part 4/4: JACC Focus Seminar

Myocardial ischemia and infarction, both in the acute and chronic phases, are associated with cardiomyocyte loss and dramatic changes in the cardiac extracellular matrix (ECM). It has long been appreciated that these changes in the cardiac ECM result in altered mechanical properties of ischemic or infarcted myocardial segments. However, a growing body of evidence now clearly demonstrates that these alterations of the ECM not only affect the structural properties of the ischemic and post-infarct heart, but they also play a crucial and sometimes direct role in mediating a range of biological pathways, including the orchestration of inflammatory and reparative processes, as well as the pathogenesis of adverse remodeling. This final part of a 4-part JACC Focus Seminar reviews the evidence on the role of the ECM in relation to the ischemic and infarcted heart, as well as its contribution to cardiac dysfunction and adverse clinical outcomes.