Lung epithelial cells interact with immune cells and bacteria to shape the microenvironment in tuberculosis

The lung epithelium has long been overlooked as a key player in tuberculosis disease. In addition to acting as a direct barrier to Mycobacterium tuberculosis (Mtb), epithelial cells (EC) of the airways and alveoli act as first responders during Mtb infections; they directly sense and respond to Mtb by producing mediators such as cytokines, chemokines and antimicrobials. Interactions of EC with innate and adaptive immune cells further shape the immune response against Mtb. These three essential components, epithelium, immune cells and Mtb, are rarely studied in conjunction, owing in part to difficulties in coculturing them. Recent advances in cell culture technologies offer the opportunity to model the lung microenvironment more closely. Herein, we discuss the interplay between lung EC, immune cells and Mtb and argue that modelling these interactions is of key importance to unravel early events during Mtb infection.

Microencapsulated Chitosan-Based Nanocapsules: A New Platform for Pulmonary Gene Delivery

In this work, we propose chitosan (CS)-based nanocapsules (NCs) for pulmonary gene delivery. Hyaluronic acid (HA) was incorporated in the NCs composition (HA/CS NCs) aiming to promote gene transfection in the lung epithelium. NCs were loaded with a model plasmid (pCMV-βGal) to easily evaluate their transfection capacity. The plasmid encapsulation efficiencies were of approx. 90%. To facilitate their administration to the lungs, the plasmid-loaded NCs were microencapsulated in mannitol (Ma) microspheres (MS) using a simple spray-drying technique, obtaining dry powders of adequate properties. In vivo, the MS reached the deep lung, where the plasmid-loaded CS-based NCs were released and transfected the alveolar cells more homogeneously than the control formulation of plasmid directly microencapsulated in Ma MS. The HA-containing formulation achieved the highest transfection efficiency, in a more extended area and more homogeneously distributed than the rest of tested formulations. The new micro-nanostructured platform proposed in this work represents an efficient strategy for the delivery of genetic material to the lung, with great potential for the treatment of genetic lung diseases.

Lung injury induces alveolar type 2 cell hypertrophy and polyploidy with implications for repair and regeneration

Epithelial polyploidization post-injury is a conserved phenomenon, recently shown to improve barrier restoration during wound healing. Whether lung injury can induce alveolar epithelial polyploidy is not known. We show that bleomycin injury induces AT2 cell hypertrophy and polyploidy. AT2 polyploidization is also seen in short term ex vivo cultures, where AT2-to-AT1 trans-differentiation is associated with substantial binucleation due to failed cytokinesis. Both hypertrophic and polyploid features of AT2 cells can be attenuated by inhibiting the integrated stress response (ISR) using the small molecule ISRIB. These data suggest that AT2 polyploidization may be a feature of alveolar epithelial injury. As AT2 cells serve as facultative progenitors for the distal lung epithelium, a propensity for injury-induced binucleation has implications for AT2 self-renewal and regenerative potential upon re-injury, which may benefit from targeting the ISR.

Benign Metastasizing Leiomyoma in the Lung Presenting in a Phyllodes-Like Pattern Mimicking a Biphasic Tumor: A Case Report

Primary biphasic tumors of the lung are rare. Lung lesions with a biphasic pattern are far more commonly primary or metastatic soft tissue tumors with entrapped native respiratory epithelium, giving the false impression of a biphasic tumor. We report a case of bilateral benign metastasizing leiomyomas in a 69-year-old female where the tumor cells diffusely entrapped native respiratory glands in a phyllodes-like pattern. The radiographic characteristics and histologic appearance were not immediately diagnostic and covered a wide differential. Reaching the final diagnosis required the use of immunohistochemical studies as well as correlation with the patient's history and radiographic findings. To the best of our knowledge, this is the first report of pulmonary benign metastasizing leiomyoma presenting in a phyllodes-like pattern. This case illustrates the importance of considering entrapment of native lung epithelium in the differential diagnosis of biphasic-appearing lung tumors.

A drug candidate for treating adverse reactions caused by pathogenic antibodies inducible by COVID-19 virus and vaccines

In a previous study, we reported that certain anti-spike antibodies of COVID-19 and SARS-CoV viruses can have a pathogenic effect through binding to sick lung epithelium cells and misleading immune responses to attack self-cells. We termed this new pathogenic mechanism Antibody Dependent Auto-Attack (ADAA). This study explores a drug candidate for prevention and treatment of such ADAA-based diseases. The drug candidate is a formulation comprising N-acetylneuraminic acid methyl ester (NANA-Me), an analog of N-acetylneuraminic acid. NANA-Me acts through a unique mechanism of action (MOA) which is repairment of the missing sialic acid on sick lung epithelium cells. This MOA can block the antibody binding to sick cells, which are vulnerable to pathogenic antibodies. Our in vivo data showed that the formulation significantly reduced the sickness and deaths caused by pathogenic anti-spike antibodies. Therefore, the formulation has the potential to prevent and treat the serious conditions caused by pathogenic antibodies during a COVID-19 infection. In addition, the formulation has potential to prevent and treat the adverse reactions of COVID-19 vaccines because the vaccines can induce similar antibodies, including pathogenic antibodies. The formulation will be helpful in increasing the safety of the vaccines without reducing the vaccine efficacy. Compared to existing antiviral drugs, the formulation has a unique MOA of targeting receptors, broad spectrum of indications, excellent safety profile, resistance to mutations, and can be easily produced.

Hormonal intervention for the treatment of veterans with COVID-19 requiring hospitalization (HITCH): a multicenter, phase 2 randomized controlled trial of best supportive care vs best supportive care plus degarelix: study protocol for a randomized controlled trial

Background Therapeutic targeting of host-cell factors required for SARS-CoV-2 entry is an alternative strategy to ameliorate COVID-19 severity. SARS-CoV-2 entry into lung epithelium requires the TMPRSS2 cell surface protease. Pre-clinical and correlative data in humans suggest that anti-androgenic therapies can reduce the expression of TMPRSS2 on lung epithelium. Accordingly, we hypothesize that therapeutic targeting of androgen receptor signaling via degarelix, a luteinizing hormone-releasing hormone (LHRH) antagonist, will suppress COVID-19 infection and ameliorate symptom severity. Methods This is a randomized phase 2, placebo-controlled, double-blind clinical trial in 198 patients to compare efficacy of degarelix plus best supportive care versus placebo plus best supportive care on improving the clinical outcomes of male Veterans who have been hospitalized due to COVID-19. Enrolled patients must have documented infection with SARS-CoV-2 based on a positive reverse transcriptase polymerase chain reaction result performed on a nasopharyngeal swab and have a severity of illness of level 3–5 (hospitalized but not requiring invasive mechanical ventilation). Patients stratified by age, history of hypertension, and severity are centrally randomized 2:1 (degarelix: placebo). The composite primary endpoint is mortality, ongoing need for hospitalization, or requirement for mechanical ventilation at 15 after randomization. Important secondary endpoints include time to clinical improvement, inpatient mortality, length of hospitalization, duration of mechanical ventilation, time to achieve a normal temperature, and the maximum severity of COVID-19 illness. Exploratory analyses aim to assess the association of cytokines, viral load, and various comorbidities with outcome. In addition, TMPRSS2 expression in target tissue and development of anti-viral antibodies will also be investigated. Discussion In this trial, we repurpose the FDA approved LHRH antagonist degarelix, commonly used for prostate cancer, to suppress TMPRSS2, a host cell surface protease required for SARS-CoV-2 cell entry. The objective is to determine if temporary androgen suppression with a single dose of degarelix improves the clinical outcomes of patients hospitalized due to COVID-19. Trial registration ClinicalTrials.gov NCT04397718. Registered on May 21, 2020

Molecular landscape of lung epithelium contributes to high severity and comorbidities for COVID-19 and lung cancer

: The heterogeneous and complex nature of cancer is extensively revealed at molecular, genetic and tissue microenvironment levels. Currently, co-occurrence of coronavirus disease 2019 (COVID-19) to lung cancer patients and severity of infections by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is being understood at preclinical and clinical levels. However, molecular and cellular insights are not discussed in those papers that support the increased COVID-19 severity and comorbidities in several cancer types, including lung cancer patients. Therefore, this perspective highlights the basis of high severity and comorbidities among lung cancer patients infected by COVID-19, emphasizing translational aspects.

Pathogenic antibodies induced by spike proteins of COVID-19 and SARS-CoV viruses

This study, using a virus-free mouse model, explores the pathogenic roles of certain antibodies specific to the spike proteins of highly pathogenic coronaviruses such as the COVID-19 and the SARS-CoV viruses. Our data showed that these pathogenic antibodies, through a mechanism of Antibody Dependent Auto-Attack (ADAA), target and bind to host vulnerable cells or tissues such as damaged lung epithelium cells, initiate a self-attack immune response, and lead to serious conditions including ARDS, cytokine release, and death. Moreover, the pathogenic antibodies also induced inflammation and hemorrhage of the kidneys, brain, and heart. Furthermore, the pathogenic antibodies can bind to unmatured fetal tissues and cause abortions, postpartum labors, still births, and neonatal deaths of pregnant mice. Novel clinical interventions, through disrupting the host-binding of these pathogenic antibodies, can be developed to fight the COVID-19 pandemic. In addition, the new concept of ADAA explored by this study may be applicable to other infectious diseases, such as the highly pathogenic influenza infections. It should be noted that the majority of anti-spike antibodies are non-pathogenic, as only 2 of 7 monoclonal antibodies tested showed significant pathogenic effects.

SARS-CoV-2 infection studies in lung organoids identify TSPAN8 as novel mediator

SARS coronavirus-2 (SARS-CoV-2) is causing a global pandemic with large variation in COVID-19 disease spectrum. SARS-CoV-2 infection requires host receptor ACE2 on lung epithelium, but epithelial underpinnings of variation are largely unknown. We capitalized on comprehensive organoid assays to report remarkable variation in SARS-CoV-2 infection rates of lung organoids from different subjects. Tropism is highest for TUBA- and MUC5AC-positive organoid cells, but levels of TUBA-, MUC5A-, or ACE2- positive cells do not predict infection rate. We identify surface molecule Tetraspanin 8 (TSPAN8) as novel mediator of SARS-CoV-2 infection, which is not downregulated by this specific virus. TSPAN8 levels, prior to infection, strongly correlate with infection rate and TSPAN8-blocking antibodies diminish SARS-CoV-2 infection. We propose TSPAN8 as novel functional biomarker and potential therapeutic target for COVID-19.