Rhinovirus and Cell Death

The complexities of cell death mechanisms: a new perspective in systemic sclerosis therapy

Systemic sclerosis, also termed scleroderma, is a severe and debilitating autoimmune disease characterized by fibrosis, an aberrant immune response, and vascular dysfunction. Cell death is essential to the body's continued normal development as it removes old or damaged cells. This process is governed by several mechanisms, including programmed cell death through apoptosis, necrosis, and pyroptosis, as well as metabolic processes, such as ferroptosis and cuproptosis. This review describes the signaling pathways associated with each form of cell death, examining the linkages between these pathways, and discussing how the dysregulation of cell death processes is involved in the development of autoimmune disorders such as systemic sclerosis. Existing and promising therapeutic strategies aimed at restoring the balance of cell death in systemic sclerosis and other autoimmune disorders are also emphasized.

Epithelial-to-mesenchymal transition and live cell extrusion contribute to measles virus release from human airway epithelia

Measles virus (MeV) is a highly contagious respiratory virus transmitted via aerosols. To understand how MeV exits the airways of an infected host, we use unpassaged primary cultures of human airway epithelial cells (HAE). MeV typically remains cell-associated in HAE and forms foci of infection, termed infectious centers, by directly spreading cell-to-cell. We previously described the phenomenon in which infectious centers detach en masse from HAE and remain viable. Here, we investigate the mechanism of this cellular detachment. Via immunostaining, we observed loss of tight junction and cell adhesion proteins within infectious centers. These morphological changes indicate activation of epithelial-to-mesenchymal transition (EMT). EMT can contribute to wound healing in respiratory epithelia by mobilizing nearby cells. Inhibiting TGF-β, and thus EMT, reduced infectious center detachment. Compared with uninfected cells, MeV-infected cells also expressed increased levels of sphingosine kinase 1 (SK1), a regulator of live cell extrusion. Live cell extrusion encourages cells to detach from respiratory epithelia by contracting the actomyosin of neighboring cells. Inhibition or induction of live cell extrusion impacted infectious center detachment rates. Thus, these two related pathways contributed to infectious center detachment in HAE. Detached infectious centers contained high titers of virus that may be protected from the environment, allowing the virus to live on surfaces longer and infect more hosts.IMPORTANCEMeasles virus (MeV) is an extremely contagious respiratory pathogen that continues to cause large, disruptive outbreaks each year. Here, we examine mechanisms of detachment of MeV-infected cells. MeV spreads cell-to-cell in human airway epithelial cells (HAE) to form groups of infected cells, termed "infectious centers". We reported that infectious centers ultimately detach from HAE as a unit, carrying high titers of virus. Viral particles within cells may be more protected from environmental conditions, such as ultraviolet radiation and desiccation. We identified two host pathways, epithelial-to-mesenchymal transition and live cell extrusion, that contribute to infectious center detachment. Perturbing these pathways altered the kinetics of infectious center detachment. These pathways influence one another and contribute to epithelial wound healing, suggesting that infectious center detachment may be a usurped consequence of the host's response to infection that benefits MeV by increasing its transmissibility between hosts.

Enhanced apoptosis and inflammation allied with autophagic and apoptotic Leishmania amastigotes in the seemingly undamaged ear skin of clinically affected dogs with canine visceral Leishmaniasis

Programmed cell death plays a relevant role in the pathogenesis of visceral Leishmaniasis. Apoptosis selects suitable parasites, regulating parasite density, whereas autophagy eliminates pathogens. This study aimed to assess the inflammation and apoptosis in inflammatory cells and presents a unique description of the presence of autophagic and apoptotic Leishmania amastigotes in naturally Leishmania-infected dogs. Fragments from seemingly undamaged ear skin of sixteen Leishmania-infected dogs and seven uninfected dogs were evaluated through histomorphometry, ultrastructural, immunohistochemical and transmission electron microscopy (TEM) analyses. Leishmania amastigotes were present on seemingly undamaged ear skin only in clinically affected dogs. Parasite load, morphometrical parameters of inflammation and apoptotic index of inflammatory cells were higher in clinically affected animals and were related to clinical manifestations. Apoptotic index and morphometric parameters of the inflammatory infiltrate in undamaged ear skin were positively correlated with parasite load. Apoptotic and non-apoptotic Leishmania amastigotes were observed within neutrophils and macrophages. Leishmania amastigotes were positive for Bax, a marker for apoptosis, by immunohistochemistry. Morphological characteristics of apoptosis and autophagy in Leishmania amastigotes were observed only in phagocytes of clinically affected dogs. Positive correlations were found between histomorphometry and clinical manifestations. Our results showed that apoptosis and autophagy in Leishmania amastigotes may be related to both the increase in parasite load and apoptotic index in inflammatory cells, and with the intensity of the inflammatory response in clinically affected dogs. Thus, our study suggests that apoptotic and autophagy Leishmania within phagocytes may have facilitate the survival of the parasite and it appears to play an important role in the process of Leishmania infection.

Rhinovirus protease cleavage of nucleoporins: perspective on implications for airway remodeling

Human Rhinoviruses (RV) are a major cause of common colds and infections in early childhood and can lead to subsequent development of asthma via an as yet unknown mechanism. Asthma is a chronic inflammatory pulmonary disease characterized by significant airway remodeling. A key component of airway remodeling is the transdifferentiation of airway epithelial and fibroblast cells into cells with a more contractile phenotype. Interestingly, transforming growth factor-beta (TGF-β), a well characterized inducer of transdifferentiation, is significantly higher in airways of asthmatics compared to non-asthmatics. RV infection induces TGF-β signaling, at the same time nucleoporins (Nups), including Nup153, are cleaved by RV proteases disrupting nucleocytoplasmic transport. As Nup153 regulates nuclear export of SMAD2, a key intermediate in the TGF-β transdifferentiation pathway, its loss of function would result in nuclear retention of SMAD2 and dysregulated TGF-β signaling. We hypothesize that RV infection leads to increased nuclear SMAD2, resulting in sustained TGF-β induced gene expression, priming the airway for subsequent development of asthma. Our hypothesis brings together disparate studies on RV, asthma and Nup153 with the aim to prompt new research into the role of RV infection in development of asthma.

Unraveling the Anticancer Potential of Statins: Mechanisms and Clinical Significance

Statins are an essential medication class in the treatment of lipid diseases because they inhibit 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase. They reduce cholesterol levels and reduce the risk of cardiovascular disease in both primary and secondary prevention. In addition to their powerful pharmacologic suppression of cholesterol production, statins appear to have pleitropic effects in a wide variety of other diseases by modulating signaling pathways. In recent years, statins have seen a large increase in interest due to their putative anticancer effects. Statins appear to cause upregulation or inhibition in key pathways involved in cancer such as inhibition of proliferation, angiogenesis, and metastasis as well as reducing cancer stemness. Further, statins have been found to induce oxidative stress, cell cycle arrest, autophagy, and apoptosis of cancer cells. Interestingly, clinical studies have shown that statin use is associated with a decreased risk of cancer formation, lower cancer grade at diagnosis, reduction in the risk of local reoccurrence, and increasing survival in patients. Therefore, our objective in the present review is to summarize the findings of the publications on the underlying mechanisms of statins' anticancer effects and their clinical implications.

Different types of cell death and their shift in shaping disease

Cell death is the irreversible stop of life. It is also the basic physiological process of all organisms which involved in the embryonic development, organ maintenance and autoimmunity of the body. In recent years, we have gained more comprehension of the mechanism in cell death and have basically clarified the different types of "programmed cell death", such as apoptosis, necroptosis, autophagy, and pyroptosis, and identified some key genes in these processes. However, in these previous studies, the conversion between different cell death modes and their application in diseases are rarely explored. To sum up, although many valued discoveries have been discovered in the field of cell death in recent years, there are still many unknown problems to be solved in this field. Facts have proved that cell death is a very complex game, and a series of core players have the ability to destroy the delicate balance of the cell environment, from survival to death, from anti-inflammatory to pro-inflammatory. With the thorough research of the complex regulatory mechanism of cell death, there will certainly be exciting new research in this field in the next few years. The sake of this paper is to emphasize the complex mechanism of overturning the balance between different cell fates and provide relevant theoretical basis for the connection between cell death transformation and disease treatment in the future.

EPs® 7630 Stimulates Tissue Repair Mechanisms and Modifies Tight Junction Protein Expression in Human Airway Epithelial Cells

Airway epithelium repair after infection consists of wound repair, re-synthesis of the extracellular matrix (ECM), and tight junction proteins. In humans, EPs^® 7630 obtained from Pelargonium sidoides roots reduces the severity and duration of acute respiratory tract infections. The effect of EPs^® 7630 on tissue repair of rhinovirus-16 (RV-16) infected and control human airway epithelial cells was assessed for: (i) epithelial cell proliferation by manual cell counts, (ii) epithelial wound repair by "scratch assay", (iii) ECM composition by Western-blotting and cell-based ELISA, and (iv) epithelial tight junction proteins by Western-blotting. EPs^® 7630 stimulated cell proliferation through cAMP, CREB, and p38 MAPK. EPs^® 7630 significantly improved wound repair. Pro-inflammatory collagen type-I expression was reduced by EPs^® 7630, while fibronectin was increased. Virus-binding tight junction proteins desmoglein2, desmocollin2, ZO-1, claudin1, and claudin4 were downregulated by EPs^® 7630. The RV16-induced shift of the ECM towards the pro-inflammatory type was prevented by EPs^® 7630. Most of the effects of EPs^® 7630 on tissue repair and regeneration were sensitive to inhibition of cAMP-induced signaling. The data suggest that EPs^® 7630-dependent modification of epithelial cell metabolism and function might underlie the faster recovery time from viral infections, as reported by others in clinical studies.

Viral Infection and Respiratory Exacerbation in Children: Results from a Local German Pediatric Exacerbation Cohort

Respiratory viruses play an important role in asthma exacerbation, and early exposure can be involved in recurrent bronchitis and the development of asthma. The exact mechanism is not fully clarified, and pathogen-to-host interaction studies are warranted to identify biomarkers of exacerbation in the early phase. Only a limited number of international exacerbation cohorts were studied. Here, we have established a local pediatric exacerbation study in Germany consisting of children with asthma or chronic, recurrent bronchitis and analyzed the viriome within the nasopharyngeal swab specimens derived from the entire cohort (n = 141). Interestingly, 41% of exacerbated children had a positive test result for human rhinovirus (HRV)/human enterovirus (HEV), and 14% were positive for respiratory syncytial virus (RSV). HRV was particularly prevalent in asthmatics (56%), wheezers (50%), and atopic (66%) patients. Lymphocytes were decreased in asthmatics and in HRV-infected subjects, and patients allergic to house dust mites were more susceptible to HRV infection. Our study thus confirms HRV infection as a strong 'biomarker' of exacerbated asthma. Further longitudinal studies will show the clinical progress of those children with a history of an RSV or HRV infection. Vaccination strategies and novel treatment guidelines against HRV are urgently needed to protect those high-risk children from a serious course of disease.