Human Vascular Pericytes and Cytomegalovirus Pathobiology.

Pericytes are multipotent cells of the vascular system with cytoplasmic extensions proximal to endothelial cells that occur along the abluminal surface of the endothelium. The interactions between endothelial cells and pericytes are essential for proper microvascular formation, development, stabilization, and maintenance. Pericytes are essential for the regulation of paracellular flow between cells, transendothelial fluid transport, angiogenesis, and vascular immunosurveillance. They also influence the chemical composition of the surrounding microenvironment to protect endothelial cells from potential harm. Dysregulation or loss of pericyte function can result in microvascular instability and pathological consequences. Human pericytes have been shown to be targets for human cytomegalovirus (HCMV) infection and lytic replication that likely contribute to vascular inflammation. This review focuses on human vascular pericytes and their permissiveness for HCMV infection. It also discusses their implication in pathogenesis in the blood⁻brain barrier (BBB), the inner blood⁻retinal barrier (IBRB), the placenta⁻blood barrier, and the renal glomerulus as well as their potential role in subclinical vascular disease.

Zika Virus Infection of the Human Glomerular Cells: Implications for Viral Reservoirs and Renal Pathogenesis.

Background: Zika virus (ZIKV) infection in the human renal compartment has not been reported. Several clinical reports have describe high-level persistent viral shedding in the urine of infected patients, but the associated mechanisms have not been explored until now. The current study examined cellular components of the glomerulus of the human kidney for ZIKV infectivity. Methods: I infected primary human podocytes, renal glomerular endothelial cells (GECs), and mesangial cells with ZIKV. Viral infectivity was analyzed by means of microscopy, immunofluorescence, real-time reverse-transcription polymerase chain reaction (RT-PCR), and quantitative RT-PCR (qRT-PCR), and the proinflammatory cytokines interleukin 1ß, interferon ß, and RANTES (regulated on activation of normal T cells expressed and secreted) were assessed using qRT-PCR. Results: I show that glomerular podocytes, renal GECs, and mesangial cells are permissive for ZIKV infection. ZIKV infectivity was confirmed in all 3 cell types by means of immunofluorescence staining, RT-PCR, and qRT-PCR, and qRT-PCR analysis revealed increased transcriptional induction of interleukin 1ß, interferon ß, and RANTES in ZIKV-infected podocytes at 72 hours, compared with renal GECs and mesangial cells. Conclusions: The findings of this study support the notion that the glomerulus may serve as an amplification reservoir for ZIKV in the renal compartment. The impact of ZIKV infection in the human renal compartment is unknown and will require further study.

Zika virus infection of cellular components of the blood-retinal barriers: implications for viral associated congenital ocular disease.

BACKGROUND: Ocular abnormalities present in microcephalic infants with presumed Zika virus (ZIKV) congenital disease includes focal pigment mottling of the retina, chorioretinal atrophy, optic nerve abnormalities, and lens dislocation. Target cells in the ocular compartment for ZIKV infectivity are unknown. The cellular response of ocular cells to ZIKV infection has not been described. Mechanisms for viral dissemination in the ocular compartment of ZIKV-infected infants and adults have not been reported. Here, we identify target cells for ZIKV infectivity in both the inner and outer blood-retinal barriers (IBRB and OBRB), describe the cytokine expression profile in the IBRB after ZIKV exposure, and propose a mechanism for viral dissemination in the retina. METHODS: We expose primary cellular components of the IBRB including human retinal microvascular endothelial cells, retinal pericytes, and Müller cells as well as retinal pigmented epithelial cells of the OBRB to the PRVABC56 strain of ZIKV. Viral infectivity was analyzed by microscopy, immunofluorescence, and reverse transcription polymerase chain reaction (RT-PCR and qRT-PCR). Angiogenic and proinflammatory cytokines were measured by Luminex assays. RESULTS: We find by immunofluorescent staining using the Flavivirus 4G2 monoclonal antibody that retinal endothelial cells and pericytes of the IBRB and retinal pigmented epithelial cells of the OBRB are fully permissive for ZIKV infection but not Müller cells when compared to mock-infected controls. We confirmed ZIKV infectivity in retinal endothelial cells, retinal pericytes, and retinal pigmented epithelial cells by RT-PCR and qRT-PCR using ZIKV-specific oligonucleotide primers. Expression profiles by Luminex assays in retinal endothelial cells infected with ZIKV revealed a marginal increase in levels of beta-2 microglobulin (ß2-m), granulocyte macrophage colony-stimulating factor (GMCSF), intercellular adhesion molecule 1 (ICAM-1), interleukin-6 (IL-6), monocyte chemotactic protein-1 (MCP1), and vascular cell adhesion molecule 1 (VCAM-1) and higher levels of regulated upon activation, normal T cell expressed and presumably secreted (RANTES) but lower levels of interleukin-4 (IL-4) compared to controls. CONCLUSIONS: Retinal endothelial cells, retinal pericytes, and retinal pigmented epithelial cells are fully permissive for ZIKV lytic replication and are primary target cells in the retinal barriers for infection. ZIKV infection of retinal endothelial cells and retinal pericytes induces significantly higher levels of RANTES that likely contributes to ocular inflammation.

Retinal pericytes and cytomegalovirus infectivity: implications for HCMV-induced retinopathy and congenital ocular disease.

BACKGROUND: Human cytomegalovirus (HCMV) is the leading infectious cause of vision loss among congenitally infected children. Retinal pericytes play an essential role in maintaining retinal vascular and endothelial cell proliferation. However, the role of retinal pericytes in ocular HCMV pathogenesis is unknown. METHODS: Retinal pericytes were exposed to clinical (SBCMV) and lab strains of HCMV; infectivity was analyzed by microscopy, immunofluorescence and qRT-PCR (reverse transcription polymerase chain reaction). Cytokine expression was examined by Luminex assay. Recombinant HCMV-GPF was used to examine viral replication kinetics. A Tricell culture model of the inner blood-retinal barrier (IBRB) was examined for cell type infectivity using immunohistochemistry. RESULTS: Retinal pericytes expressed the biomarker neuron-glial antigen 2. Antigenic expression profiles for several cytoskeletal, cell adhesion and inflammatory proteins were shared by both retinal and brain pericytes. Infected pericytes showed cytomegalic cytopathology and expressed mRNAs for the major immediate protein (MIE) and HCMV phosphorylated envelop protein 65. qRT-PCR analysis showed full lytic replication of HCMV in retinal pericytes. Pericytes exposed to SBCMV for 9 days expressed higher levels of vascular endothelial cell growth factor mRNA compared to controls. Luminex analysis of supernatants from SBCMV-infected retinal pericytes had increased levels of macrophage inflammatory protein-1α, beta-2 microglobulin (B2-m), matrix metalloproteinase-3 and -9 (MMP3/9), and lower levels of IL-6 and IL-8 compared to controls. At 24 hours post infection, pericytes expressed higher levels of IL-8, TIMP-1 (tissue inhibitor of metalloproteinase-1), and RANTES (regulated upon activation normal T cell-expressed and presumably secreted) but lower levels of MMP9. Time course analysis showed that both brain and retinal pericytes were more permissive for HCMV infection than other cellular components of the BBB (blood-brain barrier) and IBRB. Using a Tricell culture model of the IBRB (retinal endothelial, pericytes, Müller cells), retinal pericytes were most permissive for SBCMV infection. SBCMV infection of this IBRB Tricell mixture for 96 hours resulted in increased levels of IL-6, MMP9, and stem cell factor with a concomitant decrease in granulocyte-macrophage colony-stimulating factor and TNF-alpha. CONCLUSION: In retinal pericytes, HCMV induces proinflammatory and angiogenic cytokines. In the IBRB, pericytes likely serve as an amplification reservoir which contributes to retinal inflammation and angiogenesis.

Ending of the COVID-19 Related Public and National Health Emergency Declarations: Implications for Medically Underserved Populations in Tennessee.

The Biden administration decided to end the COVID-19 National and Public Health emergencies on May 11, 2023. These emergency declarations were established by the Trump Administration in early 2020. Under the COVID-19 emergency declarations, US citizens were provided with COVID-19 testing, vaccines, and treatments at little or no cost. The declarations allowed the federal government the option of waiving and or modifying government programs such Medicare, Medicaid. The emergency declarations were directly tied to other COVID-19 related provisions that have also expired that includes Economic Security (CARES) Act, the American Rescue Plan Act (ARPA), the Families First Coronavirus Response Act (FFCRA), the Coronavirus Aid, Relief, and the Inflation Reduction Act (IRA), the Consolidated Appropriations Act, 2023 (CAA). In addition, there were other federal and state emergency programs that were provided and too numerous to report here. At the time of this writing, the state of Tennessee continues to have moderate and sporadic spikes in COVID-19 cases and hospitalizations. Tennessee has higher than the national average of uninsured and underinsured people in the US. In Tennessee, more than 600,000 people are uninsured or underinsured in 2023 according to a study by the Kaiser Family Foundation. The ending of the PHE greatly impact coverage, cost, and access to COVID related services that will disproportionately affect the uninsured and medically underserved populations in Tennessee, the south in general, and throughout the US. Medically underserved populations are those groups with disparities in primary care, living in poverty, older, or having higher than expected infant mortality.

Vaccine Confidence and Uptake of the Omicron Bivalent Booster in Tennessee: Implications for Vulnerable Populations.

The COVID-19 Omicron variant and its subvariants are now the dominant variants circulating in the US. Therefore, the original COVID-19 vaccine cannot offer full protection. Instead, vaccines that target the spike proteins of the Omicron variants are warranted. Hence, the FDA recommended the development of a bivalent booster. Unfortunately, despite the safety and immunogenicity of the Omicron bivalent boosters from Pfizer and Moderna, uptake in the US has been poor. At this time, only 15.8% of individuals in the US aged five and older have received the Omicron bivalent booster (OBB). The rate is 18% for those aged 18 and older. Poor vaccine confidence and booster uptake are often fueled by misinformation and vaccine fatigue. These result in more problems associated with vaccine hesitancy, which are particular prevalent in Southern states in the US. In Tennessee, the OBB vaccination rate for eligible recipients is only 5.88% at time of writing (16 February 2023). In this review, we discuss (1) the rationale for developing the OBBs; (2) the efficacy and safety of the bivalent boosters; (3) the adverse events associated with these boosters; (4) vaccine hesitancy associated with the OBBs uptake in Tennessee; (5) implications for vulnerable populations, disparities in uptake of OBBs in Tennessee, and strategies to improve vaccine confidence and OBB uptake. In support of public health, it is essential that we continue to provide education, awareness, and vaccine access to the vulnerable and medically underserved populations in Tennessee. Receiving the OBBs is the most effective method to date of protecting the public against severe COVID disease, hospitalization, and death.

An Analysis of COVID-19 Mortality During the Dominancy of Alpha, Delta, and Omicron in the USA.

BACKGROUND: The objective of the study was to measure the risk of death due to COVID-19 in relation to individuals' characteristics, and severity of their disease during the dominant periods of Alpha, Delta, and Omicron variants have influenced mortality rates. METHODS: This study was conducted using COVID-19 Centers for Disease Control and Prevention (CDC) Case Surveillance Public Data Taskforce for 57 states, and United States territories between January 1, 2020 and March 20, 2022. Multivariable binary Hyperbolastic regression of type I was used to analyzes the data. RESULTS: Seniors and ICU-admitted patients had the highest risk of death. For each additional percent increase in fully vaccinated individuals, the odds of death deceased by 1%. The odds of death prior to vaccine availability, compared to post vaccine availability, was 1.27. When comparing the time periods each variant was dominant, the odds of death was 3.45-fold higher during Delta compared to Alpha. All predictor variables had P-values ≤.001. CONCLUSION: There was a noticeable difference in the odds of death among subcategories of age, race/ethnicity, sex, PMCs, hospitalization, ICU, vaccine availability, variant, and percent of fully vaccinated individuals.

COVID-19 Vaccine Hesitancy and Uptake among Minority Populations in Tennessee.

COVID-19 vaccine hesitancy and uptake among Southern states in the US has been problematic throughout the pandemic. To characterize COVID-19 vaccine hesitancy and uptake among medically underserved communities in Tennessee. We surveyed 1482 individuals targeting minority communities in Tennessee from 2 October 2021 to 22 June 2022. Participants who indicated that they did not plan to receive or were unsure whether to receive the COVID-19 vaccine were considered vaccine-hesitant. Among participants, 79% had been vaccinated, with roughly 5.4% not likely at all to be vaccinated in the next three months from the date that the survey was conducted. When focusing particularly on Black/AA people and white people, our survey results revealed a significant association between race (Black/AA, white, or people of mixed Black/white ancestry) and vaccination status (vaccinated or unvaccinated) (p-value = 0.013). Approximately 79.1% of all participants received at least one dose of a COVID-19 vaccine. Individuals who were concerned with personal/family/community safety and/or wanted a return to normalcy were less likely to be hesitant. The study found that the major reasons cited for refusing the COVID-19 vaccines were distrust in vaccine safety, concerns about side effects, fear of needles, and vaccine efficacy.

Infection and upregulation of proinflammatory cytokines in human brain vascular pericytes by human cytomegalovirus.

BACKGROUND: Congenital human cytomegalovirus (HCMV) infections can result in CNS abnormalities in newborn babies including vision loss, mental retardation, motor deficits, seizures, and hearing loss. Brain pericytes play an essential role in the development and function of the blood-brain barrier yet their unique role in HCMV dissemination and neuropathlogy has not been reported. METHODS: Primary human brain vascular pericytes were exposed to a primary clinical isolate of HCMV designated 'SBCMV'. Infectivity was analyzed by microscopy, immunofluorescence, Western blot, and qRT-PCR. Microarrays were performed to identify proinflammatory cytokines upregulated after SBCMV exposure, and the results validated by real-time quantitative polymerase chain reaction (qPCR) methodology. In situ cytokine expression of pericytes after exposure to HCMV was examined by ELISA and in vivo evidence of HCMV infection of brain pericytes was shown by dual-labeled immunohistochemistry. RESULTS: HCMV-infected human brain vascular pericytes as evidenced by several markers. Using a clinical isolate of HCMV (SBCMV), microscopy of infected pericytes showed virion production and typical cytomegalic cytopathology. This finding was confirmed by the expression of major immediate early and late virion proteins and by the presence of HCMV mRNA. Brain pericytes were fully permissive for CMV lytic replication after 72 to 96 hours in culture compared to human astrocytes or human brain microvascular endothelial cells (BMVEC). However, temporal transcriptional expression of pp65 virion protein after SBCMV infection was lower than that seen with the HCMV Towne laboratory strain. Using RT-PCR and dual-labeled immunofluorescence, proinflammatory cytokines CXCL8/IL-8, CXCL11/ITAC, and CCL5/Rantes were upregulated in SBCMV-infected cells, as were tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1beta), and interleukin-6 (IL-6). Pericytes exposed to SBCMV elicited higher levels of IL-6 compared to both mock-infected as well as heat-killed virus controls. A 6.6-fold induction of IL-6 and no induction TNF-alpha was observed in SBCMV-infected cell supernatants at 24 hours postinfection. Using archival brain tissue from a patient coinfected with HCMV and HIV, we also found evidence of HCMV infection of pericytes using dual-label immunohistochemistry, as monitored by NG2 proteoglycan staining. CONCLUSION: HCMV lytic infection of primary human brain pericytes suggests that pericytes contribute to both virus dissemination in the CNS as well as neuroinflammation.

KSHV regulation of fibulin-2 in Kaposi's sarcoma: implications for tumorigenesis.

Kaposi's sarcoma is an angioproliferative tumor caused by Kaposi's sarcoma-associated herpesvirus (KSHV) infection of vascular endothelial cells. Fibulins, proteins that associate with extracellular matrix (ECM) proteins, may have both tumor-suppressive and oncogenic activities. We found that the expression of fibulin-2 protein and mRNA were decreased 50-fold and 26-fold, respectively, in 10-day KSHV-infected dermal microvascular endothelial cells (DMVEC). Using quantitative RT-PCR, we found a fivefold and 25-fold decrease of fibulin-2 extracellular matrix binding partners, fibronectin and tropoelastin, respectively. Time-course transcriptional analyses over 10 days showed that in addition to that of fibulin-2, expression of fibulins 3 and 5 was decreased in KSHV-infected DMVEC, fibulins 1C/1D were increased, and fibulins 4, 6, and 7 were unchanged. KSHV latency-associated nuclear antigen (LANA) transcription levels rose consistently over the same period. Addition of recombinant fibulin-3 or -5 for 48 hours to 10-day KSHV-infected cells caused a suppression of KSHV-induced vascular endothelial growth factor (VEGF) protein and mRNA levels. Recombinant fibulin-3 also significantly reduced VEGF receptor 3 expression. In pleural effusion lymphoma cell lines that express variable levels of KSHV lytic replication, we observed no detectable fibulin-2 or -5 expression. Finally, fibulin-2 expression was decreased in tissue microarrays from KSHV-infected, LANA-positive patient cells as compared to that in patient nontumor controls. Understanding the interactions between KSHV and the fibulins may lead to the development of novel therapies for treatment of Kaposi's sarcoma.

Breakthrough COVID-19 Infections in the US: Implications for Prolonging the Pandemic.

The incidence of COVID-19 breakthrough infections-an infection that occurs after you have been vaccinated-has increased in frequency since the Delta and now Omicron variants of the SARS-CoV-2 coronavirus have become the dominant strains transmitted in the United States (US). Evidence suggests that individuals with breakthrough infections, though rare and expected, may readily transmit COVID-19 to unvaccinated populations, posing a continuing threat to the unvaccinated. Here, we examine factors contributing to breakthrough infections including a poor immune response to the vaccines due to the fact of advanced age and underlying comorbidities, the natural waning of immune protection from the vaccines over time, and viral variants that escape existing immune protection from the vaccines. The rise in breakthrough infections in the US and how they contribute to new infections, specifically among the unvaccinated and individuals with compromised immune systems, will create the need for additional booster vaccinations or development of modified vaccines that directly target current variants circulating among the general population. The need to expedite vaccination among the more than 49.8 million unvaccinated eligible people in the US is critical.

Meharry Medical College Mobile Vaccination Program: Implications for Increasing COVID-19 Vaccine Uptake among Minority Communities in Middle Tennessee.

To end or curtail the COVID-19 pandemic, it is essential to incorporate mobile vaccination programs into the national vaccination strategy. Mobile COVID-19 vaccination programs play an important role in providing comprehensive vaccination from federally qualified institutions to underserved communities facing a higher risk for COVID-19 acquisition. The Meharry Medical College COVID-19 mobile vaccine program (MMC-MVP) has provided lifesaving COVID-19 vaccines, free of charge, to communities throughout Middle Tennessee. Mobile deployment is vital for those forced to travel long distances to get vaccinated and who have limited access to medical providers or vaccine clinics, lack access to public transportation, or may be homebound. The MMC-MVP, established on 13 April 2021, via funding from the Bloomberg Foundation, is sourced with infectious disease experts, nurse practitioners, and community engagement personnel to provide COVID-19 vaccinations and information in a culturally competent manner to diverse communities in Middle Tennessee. To provide broader access to COVID-19 vaccinations and vaccine-related information, the MMC-MVP partnered with the Tennessee Community Engagement Alliance, Vanderbilt University School of Nursing COVID-19 vaccine strike teams, non-academic, community-based organizations, and faith-based organizations. During the September 2021 COVID-19 surge in Tennessee, the MMC-MVP provided nearly 5000 free COVID-19 vaccinations to targeted, underserved communities. The MMC-MVP has provided vaccine equity in communities with the highest risk for acquiring COVID-19 and with greatest need in this pandemic.

The COVID-19 Vaccine and Pregnant Minority Women in the US: Implications for Improving Vaccine Confidence and Uptake.

The American College of Obstetricians and Gynecologists (AGOG) recommends the FDA-approved Pfizer and Moderna mRNA COVID-19 vaccines and boosters for all eligible pregnant women in the US. However, COVID-19 vaccine confidence and uptake among pregnant minority women have been poor. While the underlying reasons are unclear, they are likely to be associated with myths and misinformation about the vaccines. Direct and indirect factors that deter minority mothers in the US from receiving the mRNA COVID-19 vaccines require further investigation. Here, we examine the historical perspectives on vaccinations during pregnancy. We will examine the following aspects: (1) the influenza and tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccinations during pregnancy; (2) the exclusion of pregnant and lactating women from COVID-19 vaccine trials; (3) COVID-19 vaccine safety during pregnancy, obstetric complications associated with symptomatic COVID-19 during pregnancy, COVID-19 vaccine hesitancy among pregnant minority women, and racial disparities experienced by pregnant minority women due to the COVID-19 pandemic as well as their potential impact on pregnancy care; and (4) strategies to improve COVID-19 vaccine confidence and uptake among pregnant minority women in the US. COVID-19 vaccine hesitancy among minority mothers can be mitigated by community engagement efforts that focus on COVID-19 vaccine education, awareness campaigns by trusted entities, and COVID-19-appropriate perinatal counseling aimed to improve COVID-19 vaccine confidence and uptake.

Targeting COVID Vaccine Hesitancy in Rural Communities in Tennessee: Implications for Extending the COVID-19 Pandemic in the South.

Approximately 40% of Tennesseans are vaccinated fully, due mainly to higher vaccination levels within urban counties. Significantly lower rates are observed in rural counties. Surveys suggest COVID-19 vaccine hesitancy is entrenched mostly among individuals identifying as white, rural, Republican, and evangelical Christian. Rural counties represent 70 of the total 95 counties in Tennessee, and vaccine hesitancy signifies an immediate public health crisis likely to extend the COVID-19 pandemic. Tennessee is a microcosm of the pandemic's condition in the Southern U.S. Unvaccinated communities are the greatest contributors of new COVID-19 infections, hospitalizations, and deaths. Rural Tennesseans have a long history of cultural conservatism, poor health literacy, and distrust of government and medical establishments and are more susceptible to misinformation and conspiracy theories. Development of novel strategies to increase vaccine acceptance is essential. Here, I examine the basis of COVID-19 following SARS-CoV-2 infection and summarize the pandemic's extent in the South, current vaccination rates and efforts across Tennessee, and underlying factors contributing to vaccine hesitancy. Finally, I discuss specific strategies to combat COVID-19 vaccine hesitancy. We must develop novel strategies that go beyond financial incentives, proven ineffective toward vaccinations. Successful strategies for vaccine acceptance of rural Tennesseans could increase acceptance among unvaccinated rural U.S. populations.

Targeting COVID-19 Vaccine Hesitancy in Minority Populations in the US: Implications for Herd Immunity.

There has been a continuous underrepresentation of minorities in healthcare research and vaccine trials, along with long-standing systemic racism and discrimination that have been fueling the distrust of the healthcare system among these communities for decades. The history and legacy of racial injustices and negative experiences within a culturally insensitive healthcare system have greatly contributed to vaccine hesitancy among ethnic minorities. COVID-19 vaccine hesitancy will impact vaccine uptake in the US, subsequently hindering the establishment of herd immunity (75-85% of the population vaccinated) to mitigate SARS-CoV-2 infection and transmission. Information targeting underserved racial/ethnic minorities in the US in a culturally competent manner has been lacking. This information is crucial for educating these communities about COVID-19 vaccines and their distribution as well as dispelling misinformation regarding vaccine trials, safety, and efficacy. This lack of education has greatly contributed to COVID-19 vaccine hesitancy and will increase disparities in vaccine uptake. Moreover, timely vaccinations are also essential to curtailing virus transmission and the emergence of SARS-CoV-2 variants that may evade the immune response produced by the three existing COVID-19 vaccines.

Vivo-Morpholino-Based Antiviral for SARS-CoV-2: Implications for Novel Therapies in the Treatment of Acute COVID-19 Disease.

Therapeutic modalities designed specifically to inhibit COVID-19 infection and replication would limit progressive COVID-19-associated pulmonary disease in infected patients and prevent or limit systemic disease. If effective, antivirals could reduce viral transmission rates by reducing viral burden and allow time for immune clearance. For individuals infected with acute-stage disease, antivirals in support of the existing vaccines could reduce COVID-19 hospitalizations and deaths. Here, we evaluate MRCV-19, a phosphorodiamidate morpholino oligo with delivery dendrimer (Vivo-Morpholino), to prevent coronavirus infection in a cell culture model. This is a novel antiviral that effectively inhibits SARS-CoV-2 replication in vitro. By design, MRCV-19 targets the SARS-CoV-2 5'UTR and overlaps the pp1a start site of translation in order to block access of the translation initiation complex to the start. MRCV-19 testing is conducted in a high-throughput, 384-well plate format with a 10-point dose-response curve (common ratio of 2) assayed in duplicate with parallel cytotoxicity evaluations. MRCV-19 was shown to be more effective than hydroxychloroquine and remdesivir in our CPE reduction assay with low toxicity. The clinical translational impact of this study is providing the basis for evaluating MRCV-19 on a large scale in an appropriate infection model for toxicity and systemic high-level inhibition of SARS-CoV-2, which could lead in time to phase I testing in humans.

Cytotrophoblasts suppress macrophage-mediated inflammation through a contact-dependent mechanism.

PROBLEM: Gestational membrane (GM) infection provokes inflammation and can result in preterm prelabor rupture of membranes (PPROM). The choriodecidual layer of the GM includes decidual stromal cells (DSC), cytotrophoblasts (CTB), and macrophages (Mφ). Our laboratory has previously shown that DSCs suppress Mφ TNF-α production through secreted prostaglandin E2 . We hypothesized that CTBs would also inhibit Mφ cytokine expression through secreted mediators. METHOD OF STUDY: THP.1 Mφ-like cells with an NF-κB reporter construct or human blood monocyte-derived Mφ were co-cultured with the Jeg3 CTB cell line or primary human CTBs and challenged with group B streptococcus (GBS) or Toll-like receptor (TLR) agonists. Conditioned medium generated from CTB cultures was applied to Mφ cultures before infection or treatment. Alternatively, CTBs were co-incubated with, but physically separated from, Mφ and GBS or TLR-stimulated. NF-κB was assessed via alkaline phosphatase assay, and proinflammatory mediators were assessed by qRT-PCR and ELISA. RESULTS: CTBs suppressed GBS- or TLR-stimulated Mφ NF-κB activity, and TNF-α and MMP9 production. Direct physical contact between CTBs and Mφ was required for full immunosuppression. Immunosuppression could be overcome by increasing the ratio of Mφ to CTB. CONCLUSIONS: CTBs limit Mφ NF-κB activation and production of TNF-α and MMP9 through an as-yet unknown, cell-to-cell contact-mediated mechanism. This suppression is distinct from the PGE2 -mediated Mφ TNF-α suppression by DSC, suggesting that DSCs and CTBs regulate Mφ inflammation through distinct mechanisms. How Mφ integrates these signals in an intact GM will be paramount to determining causes and prevention of PPROM.

KSHV downregulation of galectin-3 in Kaposi's sarcoma.

Galectins are a family of proteins that share an affinity for beta-galactoside containing glycoconjugates. In prostate, ovarian and breast cancer, downregulation of galectin-3 is associated with malignancy and tumor progression. Kaposi's sarcoma (KS) is characterized as an angioproliferative tumor of vascular endothelial cells and produces rare B cell lymphoproliferative diseases in the form of primary effusion lymphomas and some forms of multicentric Castleman's disease. Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent of KS. We found reduced levels of galectin-3 expression in a significant fraction of latency-associated nuclear antigen (LANA)-positive spindle cell regions in human archival KS tissue and as measured in KS tissue microarrays. Here we demonstrate that galectin-3 protein expression is downregulated 10-fold in 10-day KSHV-infected dermal microvascular endothelial cells (DMVEC) accompanied by downregulation of message. There is loss of galectin-3 staining in KSHV-infected DMVEC by dual labeled immunohistochemistry in LANA-positive spindle cells. We observed a consistent downregulation of galectin-3 by time-course transcriptional analysis. Of the galectins assayed, only galectin-1 was also downregulated in KSHV-infected DMVEC. We examined 86 KS tumors; 19 were LANA positive (22%) and 67 LANA negative (78%). All 86 tumors were found to be galectin-3 positive; 11 of 19 showed reduced expression of galectin-3 in LANA-positive spindle cell regions. Our data suggest that KSHV vFLIP and LANA are the viral genes targeting galectin-3 downregulation. The contribution of host factors to the pathogenesis of KS is essential for early detection and development of innovative therapies for treatment.

Racial Disparities-Associated COVID-19 Mortality among Minority Populations in the US.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a betacoronavirus that causes the novel coronavirus disease 2019 (COVID-19), is highly transmissible and pathogenic for humans and may cause life-threatening disease and mortality, especially in individuals with underlying comorbidities. First identified in an outbreak in Wuhan, China, COVID-19 is affecting more than 185 countries and territories around the world, with more than 15,754,651 confirmed cases and more than 640,029 deaths. Since December 2019, SARS-CoV-2 transmission has become a global threat, which includes confirmed cases in all 50 states within the United States (US). As of 25 July 2020, the Johns Hopkins Whiting School of Engineering Center for Systems Science and Engineering reports more than 4,112,651 cases and 145,546 deaths. To date, health disparities are associated with COVID-19 mortality among underserved populations. Here, the author explores potential underlying reasons for reported disproportionate, increased risks of mortality among African Americans and Hispanics/Latinos with COVID-19 compared with non-Hispanic Whites. The author examines the underlying clinical implications that may predispose minority populations and the adverse clinical outcomes that may contribute to increased risk of mortality. Government and community-based strategies to safeguard minority populations at risk for increased morbidity and mortality are essential. Underserved populations living in poverty with limited access to social services across the US are more likely to have underlying medical conditions and are among the most vulnerable. Societal and cultural barriers for ethnic minorities to achieve health equity are systemic issues that may be addressed only through shifts in governmental policies, producing long-overdue, substantive changes to end health care inequities.

Dysregulation of Endothelin-1: Implications for Health Disparities in Alzheimer's Disease.

Alzheimer's disease (AD) and related dementias disproportionately impact racial and ethnic minorities. The racial and ethnic disparities in AD could be explained by differences in cerebral vascular disease pathology. Endothelin-1 (ET-1) is a potent vasoconstrictive peptide that regulates smooth muscle, endothelial cell, and pericyte contractions that may result in cerebral vascular constriction, leading to cerebral hypoperfusion; over time, ET-1 may result in neuronal injury contributing to the pathology of AD. Upregulation of the ET-1 system has been observed in African Americans when compared with non-Hispanic Whites. The role of the ET-1 system as a driver of ethnic disparities in AD requires further investigation. Targeting of the ET-1 system as a therapeutic intervention that could impact AD progression also needs further study. Dysregulation of ET-1 in Hispanic/Latino populations largely have been unexplored. Genetics linking ET-1 dysregulation and racial disparities in AD also needs further investigation. In this review, I examine how AD effects underserved minority populations and how dysregulation of the ET-1 system specifically predisposes ethnic minorities to AD. In addition, I examine the molecular interactions of the ET-1 system and amyloid beta, the role the ET-1 system in neurodegeneration, potential therapeutics for ET-1 dysregulation, and the impact on AD progression.