m6A Modification Prevents Formation of Endogenous Double-Stranded RNAs and Deleterious Innate Immune Responses during Hematopoietic Development.

N6-methyladenosine (m6A) is the most abundant RNA modification, but little is known about its role in mammalian hematopoietic development. Here, we show that conditional deletion of the m6A writer METTL3 in murine fetal liver resulted in hematopoietic failure and perinatal lethality. Loss of METTL3 and m6A activated an aberrant innate immune response, mediated by the formation of endogenous double-stranded RNAs (dsRNAs). The aberrantly formed dsRNAs were long, highly m6A modified in their native state, characterized by low folding energies, and predominantly protein coding. We identified coinciding activation of pattern recognition receptor pathways normally tasked with the detection of foreign dsRNAs. Disruption of the aberrant immune response via abrogation of downstream Mavs or Rnasel signaling partially rescued the observed hematopoietic defects in METTL3-deficient cells in vitro and in vivo. Our results suggest that m6A modification protects against endogenous dsRNA formation and a deleterious innate immune response during mammalian hematopoietic development.

APOBEC3A regulates transcription from interferon-stimulated response elements.

APOBEC3A (A3A) is a cytidine deaminase that inactivates a variety of viruses through introduction of lethal mutations to the viral genome. Additionally, A3A can suppress HIV-1 transcription in a deaminase-independent manner by binding to the long terminal repeat of proviral HIV-1. However, it is unknown whether A3A targets additional host genomic loci for repression. In this study, we found that A3A suppresses gene expression by binding TTTC doublets that are in close proximity to each other. However, one TTTC motif is sufficient for A3A binding. Because TTTC doublets are present in interferon (IFN)-stimulated response elements (ISRE), we hypothesized that A3A may impact IFN-stimulated gene (ISG) expression. After scanning the human genome for TTTC doublet occurrences, we discovered that these motifs are enriched in the proximal promoters of genes associated with antiviral responses and type I IFN (IFN-I) signaling. As a proof of principle, we examined whether A3A can impact ISG15 expression. We found that A3A binding to the ISRE inhibits phosphorylated STAT-1 binding and suppresses ISG15 induction in response to IFN-I treatment. Consistent with these data, our RNA-sequencing analyses indicate that A3A loss results in increased IFN-I­dependent induction of several ISGs. This study revealed that A3A plays an unexpected role in ISG regulation and suggests that A3A contributes to a negative feedback loop during IFN signaling.

Detection of SARS-CoV-2 RNA by multiplex RT-qPCR.

The current quantitative reverse transcription PCR (RT-qPCR) assay recommended for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing in the United States requires analysis of 3 genomic targets per sample: 2 viral and 1 host. To simplify testing and reduce the volume of required reagents, we devised a multiplex RT-qPCR assay to detect SARS-CoV-2 in a single reaction. We used existing N1, N2, and RP primer and probe sets by the Centers for Disease Control and Prevention, but substituted fluorophores to allow multiplexing of the assay. The cycle threshold (Ct) values of our multiplex RT-qPCR were comparable to those obtained by the single assay adapted for research purposes. Low copy numbers (≥500 copies/reaction) of SARS-CoV-2 RNA were consistently detected by the multiplex RT-qPCR. Our novel multiplex RT-qPCR improves upon current single diagnostics by saving reagents, costs, time, and labor.

Low ambient humidity impairs barrier function and innate resistance against influenza infection.

In the temperate regions, seasonal influenza virus outbreaks correlate closely with decreases in humidity. While low ambient humidity is known to enhance viral transmission, its impact on host response to influenza virus infection and disease outcome remains unclear. Here, we showed that housing Mx1 congenic mice in low relative humidity makes mice more susceptible to severe disease following respiratory challenge with influenza A virus. We find that inhalation of dry air impairs mucociliary clearance, innate antiviral defense, and tissue repair. Moreover, disease exacerbated by low relative humidity was ameliorated in caspase-1/11-deficient Mx1 mice, independent of viral burden. Single-cell RNA sequencing revealed that induction of IFN-stimulated genes in response to viral infection was diminished in multiple cell types in the lung of mice housed in low humidity condition. These results indicate that exposure to dry air impairs host defense against influenza infection, reduces tissue repair, and inflicts caspase-dependent disease pathology.

Association between changes in subcutaneous fat mass and heart failure-induced cachexia: a case report.

[Purpose] We investigated whether an increase or decrease in subcutaneous fat mass secondary to cardiac cachexia can be evaluated using diagnostic ultrasonography in patients with heart failure. [Participant and Methods] We report a case of cardiac cachexia in a patient in whom cachexia was confirmed by weight loss, decreased dietary intake, and biochemical indicators measured by blood tests. We measured the subcutaneous fat mass in the patient's thigh using ultrasonic diagnostic equipment during the cachectic state, as well as 1 and 2 months later. [Results] An increase in weight and ultrasonographically documented femoral subcutaneous fat mass was confirmed by improvement in heart failure-induced cachexia. [Conclusion] Clinically convenient ultrasonic diagnostic equipment is useful to assess subcutaneous fat mass, which serves as an indicator of the degree of cachexia.

Inhibition of autophagy by chloroquine induces apoptosis in primary effusion lymphoma in vitro and in vivo through induction of endoplasmic reticulum stress.

Autophagy plays a crucial role in cancer cell survival and the inhibition of autophagy is attracting attention as an emerging strategy for the treatment of cancer. Chloroquine (CQ) is an anti-malarial drug, and is also known as an inhibitor of autophagy. Recently, it has been found that CQ induces cancer cell death through the inhibition of autophagy; however, the underlying mechanism is not entirely understood. In this study, we identified the role of CQ-induced cancer cell death using Primary Effusion Lymphoma (PEL) cells. We found that a CQ treatment induced caspase-dependent apoptosis in vitro. CQ also suppressed PEL cell growth in a PEL xenograft mouse model. We showed that CQ activated endoplasmic reticulum (ER) stress signal pathways and induced CHOP, which is an inducer of apoptosis. CQ-induced cell death was significantly decreased by salbrinal, an ER stress inhibitor, indicating that CQ-induced apoptosis in PEL cells depended on ER stress. We show here for the first time that the inhibition of autophagy induces ER stress-mediated apoptosis in PEL cells. Thus, the inhibition of autophagy is a novel strategy for cancer chemotherapy.

COMMD1/Murr1 reinforces HIV-1 latent infection through IκB-α stabilization.

UNLABELLED: The transcription factor NF-κB is important for HIV-1 transcription initiation in primary HIV-1 infection and reactivation in latently HIV-1-infected cells. However, comparative analysis of the regulation and function of NF-κB in latently HIV-1-infected cells has not been done. Here we show that the expression of IκB-α, an endogenous inhibitor of NF-κB, is enhanced by latent HIV-1 infection via induction of the host-derived factor COMMD1/Murr1 in myeloid cells but not in lymphoid cells by using four sets of latently HIV-1-infected cells and the respective parental cells. IκB-α protein was stabilized by COMMD1, which attenuated NF-κB signaling during Toll-like receptor ligand and tumor necrosis factor alpha treatment and enhanced HIV-1 latency in latently HIV-1-infected cells. Activation of the phosphoinositol 3-kinase (PI3K)-JAK pathway is involved in COMMD1 induction in latently HIV-1-infected cells. Our findings indicate that COMMD1 induction is the NF-κB inhibition mechanism in latently HIV-1-infected cells that contributes to innate immune deficiency and reinforces HIV-1 latency. Thus, COMMD1 might be a double-edged sword that is beneficial in primary infection but not beneficial in latent infection when HIV-1 eradication is considered. IMPORTANCE: HIV-1 latency is a major barrier to viral eradication in the era of combination antiretroviral therapy. In this study, we found that COMMD1/Murr1, previously identified as an HIV-1 restriction factor, inhibits the proteasomal degradation of IκB-α by increasing the interaction with IκB-α in latently HIV-1-infected myeloid cells. IκB-α protein was stabilized by COMMD1, which attenuated NF-κB signaling during the innate immune response and enhanced HIV-1 latency in latently HIV-1-infected cells. Activation of the PI3K-JAK pathway is involved in COMMD1 induction in latently HIV-1-infected cells. Thus, the host-derived factor COMMD1 is beneficial in suppressing primary infection but enhances latent infection, indicating that it may be a double-edged sword in HIV-1 eradication.

Inhibition of carbonic anhydrase potentiates bevacizumab treatment in cholangiocarcinoma.

Cholangiocarcinoma (CCA) is a unique liver cancer subtype with an increasing incidence globally. The lack of specific symptoms and definite diagnostic markers results in a delayed diagnosis and disease progression. Systemic chemotherapy is commonly selected for advanced CCA even though its advantages remain unknown. Targeted therapy, especially anti-vascular endothelial growth factor (VEGF) therapy, is promising for CCA; however, improvements in the therapeutic regimen are necessary to overcome subsequent resistance. We demonstrated VEGF expression was higher in CCA cell lines than in other liver cancer cells. Secreted VEGFs played roles in the induction of peri- and intra-tumoral vascularization. VEGF neutralization by bevacizumab effectively reduced tumor growth, mainly through the suppression of angiogenesis; however, increases in the expression of hypoxia-inducible factor 1α (HIF1α) and HIF1α-responsive genes (such as VEGF, VEGFR1, VEGFR2, carbonic anhydrase (CA) IX and CAXII) indicated the potential for subsequent therapeutic resistance. Supplementation with a carbonic anhydrase inhibitor, acetazolamide, enhanced the anti-CCA effects of bevacizumab. Anti-angiogenesis and anti-proliferation were observed with the combination treatment. These results suggested a novel treatment strategy to overcome anti-angiogenesis resistance and the importance of "induced essentiality" in the treatment of CCA.

The ETS Factor Myeloid Elf-1-Like Factor (MEF)/Elf4 Is Transcriptionally and Functionally Activated by Hypoxia.

Hypoxia-inducible factor (HIF)-1α is a transcription factor belonging to the HIF family that is activated in mammalian cells during conditions of low oxygen tension or hypoxia to induce an adaptive response and promote cell survival. Some of the genes targeted by HIF-1α are important for angiogenesis and proliferation. Here, we found that the E26 transformation-specific (ETS) transcription factor myeloid elf-1-like factor (MEF)/Elf4 is activated by HIF-1α. MEF induces genes such as human beta-defensin 2 (HßD2) and perforin (PRF1), and is known to affect the cell cycle. Treatment with hypoxia mimetic CoCl2 or low O2 incubation up-regulated MEF mRNA and protein levels in various cell lines. HIF-1α overexpression in HEK293 cells also increased MEF mRNA and protein levels. In contrast, HIF-1α knockdown by small interfering RNA (siRNA) suppressed the induction of MEF in response to hypoxia. HIF-1α binds to the hypoxia response element in the MEF promoter region (-200 bp) and activates MEF promoter under hypoxia condition. The induction of MEF by hypoxia/HIF-1α correlated with the increase of MEF target genes HßD2 and PRF1. Intriguingly, the hypoxia-induced expression of HIF-1α target gene vascular endothelial growth factor (VEGF) was enhanced by the exogenous addition of MEF. Overall, these data indicate that hypoxia or HIF-1α positively regulates MEF expression and function.

Inhibition of HIV-1 entry by the tricyclic coumarin GUT-70 through the modification of membrane fluidity.

Membrane fusion between host cells and HIV-1 is the initial step in HIV-1 infection, and plasma membrane fluidity strongly influences infectivity. In the present study, we demonstrated that GUT-70, a natural product derived from Calophyllum brasiliense, stabilized plasma membrane fluidity, inhibited HIV-1 entry, and down-regulated the expression of CD4, CCR5, and CXCR4. Since GUT-70 also had an inhibitory effect on viral replication through the inhibition of NF-κB, it is expected to be used as a dual functional and viral mutation resistant reagent. Thus, these unique properties of GUT-70 enable the development of novel therapeutic agents against HIV-1 infection.

Inhibition of HIV-1 replication by a tricyclic coumarin GUT-70 in acutely and chronically infected cells.

The anti-HIV-1 activity of GUT-70, a natural product derived from the stem bark of Chlophyllum brasiliense, was evaluated. GUT-70 inhibited HIV-1 replication in both acutely and chronically infected cells through suppression of NF-κB. Our results strengthen the idea that NF-κB pathway is one of the potential targets to control HIV-1 replication and that GUT-70 could serve as a lead compound to develop novel therapeutic agents against HIV-1 infection.

Posterior reversible encephalopathy syndrome associated with mild COVID-19 infection in a 9-year-old child: A case report and literature review.

The neurologic complications associated with the coronavirus disease 2019 (COVID-19) is becoming more prevalent in children after the appearance of the Omicron strain. An association between COVID-19 and posterior reversible encephalopathy (PRES) has been consistently reported in adults, but little information is available in the pediatric age group. There are only few case reports of COVID-19-related PRES in children, and all of these patients were either on some type of immunomodulatory medications or whose general condition was severe. The present case, a 9-year-old Japanese boy, who had no fever but vomited several times from days 1-4 of a COVID-19 infection had an afebrile seizure on the 8th day of his illness. The patient had no history of hypertension, and had not previously been administered any immunosuppressive drugs before or during the period of his COVID-19 infection. On admission, his physical findings were unremarkable, except for a high blood pressure. The results obtained by brain computed tomography and magnetic resonance imaging were consistent with PRES. The patient recovered with no sequelae after treatment with antihypertensive drugs. Further investigations did not suggest any underlying disease that could have caused the transient hypertension. Although PRES is relatively rare in children, pediatricians should keep in mind that this syndrome can be complicated, even in children with mild COVID-19 infections.

Antitumor effect of berberine against primary effusion lymphoma via inhibition of NF-κB pathway.

Primary effusion lymphoma (PEL) is an infrequent and distinct entity among the aggressive non-Hodgkin B cell lymphomas that occurs predominantly in patients with advanced AIDS. It shows serous lymphomatous effusion in body cavities, and is resistant to conventional chemotherapy with a poor prognosis. Thus, the optimal treatment for PEL is not well defined and there is a need for novel agents. PEL has been recognized as the tumor caused by Kaposi sarcoma-associated herpes virus/human herpes virus-8 (KSHV/HHV-8), and nuclear factor (NF)-κB activation plays a critical role in the survival and growth of PEL cells. In this study, we assessed the antitumor effect of berberine, a naturally occurring isoquinoline alkaloid, on this pathway. The methylthiotetrazole assay showed that cell proliferation in the PEL cell lines was inhibited by berberine. Berberine also induced caspase-dependent apoptosis and suppressed NF-κB activity by inhibiting IκB kinase (IKK) phosphorylation, IκB phosphorylation and IκB degradation, upstream targets of the NF-κB pathway, in PEL cells. In a xenograft mouse model that showed ascites and diffuse organ invasion of PEL cells, treatment with berberine inhibited the growth and invasion of PEL cells significantly compared with untreated mice. These results show that the suppression of NF-κB is a molecular target for treating PEL, and berberine is a potential antitumor agent for PEL.

LINE-1 activation in the cerebellum drives ataxia.

Dysregulation of long interspersed nuclear element 1 (LINE-1, L1), a dominant class of transposable elements in the human genome, has been linked to neurodegenerative diseases, but whether elevated L1 expression is sufficient to cause neurodegeneration has not been directly tested. Here, we show that the cerebellar expression of L1 is significantly elevated in ataxia telangiectasia patients and strongly anti-correlated with the expression of epigenetic silencers. To examine the role of L1 in the disease etiology, we developed an approach for direct targeting of the L1 promoter for overexpression in mice. We demonstrated that L1 activation in the cerebellum led to Purkinje cell dysfunctions and degeneration and was sufficient to cause ataxia. Treatment with a nucleoside reverse transcriptase inhibitor blunted ataxia progression by reducing DNA damage, attenuating gliosis, and reversing deficits of molecular regulators for calcium homeostasis in Purkinje cells. Our study provides the first direct evidence that L1 activation can drive neurodegeneration.

SalivaDirect: A simplified and flexible platform to enhance SARS-CoV-2 testing capacity.

BACKGROUND: Scaling SARS-CoV-2 testing to meet demands of safe reopenings continues to be plagued by assay costs and supply chain shortages. In response, we developed SalivaDirect, which received Emergency Use Authorization (EUA) from the U.S. Food and Drug Administration (FDA). METHODS: We simplified our saliva-based diagnostic test by (1) not requiring collection tubes with preservatives, (2) replacing nucleic acid extraction with a simple enzymatic and heating step, and (3) testing specimens with a dualplex qRT-PCR assay. Moreover, we validated SalivaDirect with reagents and instruments from multiple vendors to minimize supply chain issues. FINDINGS: From our hospital cohort, we show a high positive agreement (94%) between saliva tested with SalivaDirect and nasopharyngeal swabs tested with a commercial qRT-PCR kit. In partnership with the National Basketball Association (NBA) and National Basketball Players Association (NBPA), we tested 3,779 saliva specimens from healthy individuals and detected low rates of invalid (0.3%) and false-positive (<0.05%) results. CONCLUSIONS: We demonstrate that saliva is a valid alternative to swabs for SARS-CoV-2 screening and that SalivaDirect can make large-scale testing more accessible and affordable. Uniquely, we can designate other laboratories to use our sensitive, flexible, and simplified platform under our EUA (https://publichealth.yale.edu/salivadirect/). FUNDING: This study was funded by the NBA and NBPA (N.D.G.), the Huffman Family Donor Advised Fund (N.D.G.), a Fast Grant from Emergent Ventures at the Mercatus Center at George Mason University (N.D.G.), the Yale Institute for Global Health (N.D.G.), and the Beatrice Kleinberg Neuwirth Fund (A.I.K.). C.B.F.V. is supported by NWO Rubicon 019.181EN.004.

Environmental Conditioning and Aerosol Infection of Mice.

Influenza infection models in mice are widely used to study flu-mediated immune responses and pathology. However, most laboratory mice are housed at 20 °C and 50% relative humidity (RH). To better recapitulate influenza epidemics and immune responses during winter seasons, mice were housed at 20 °C under different humidity conditions, 10-20% or 50% RH. Here, we describe a protocol for using aerosolized droplets to infect mice with influenza under different environmental conditions. Using this method enables influenza infection studies performed under more physiologically relevant conditions which better mimics human viral exposure.

Efficacy of sodium-glucose cotransporter 2 inhibitor with glucagon-like peptide-1 receptor agonist for the glycemic control of a patient with Prader-Willi syndrome: a case report.

Prader-Willi syndrome (PWS) is often related to severe obesity and diabetes mellitus (DM). Clinical findings suggesting the benefits of glucagon-like peptide-1 (GLP-1) receptor agonists for glycemic control of DM in PWS have been recently increasing. However, there are only a few reports describing the effects of sodium-glucose cotransporter 2 (SGLT2) inhibitors for PWS. We present a diabetic female with PWS, whose glycemic control was deteriorated at the age of 19 but improved to a certain extent by introducing the GLP-1 analog liraglutide. At the age of 20, the SGLT2 inhibitor empagliflozin was administered. Subsequently, her HbA1c level and body weight markedly decreased. Improvement in both insulin resistance and secretion was observed during the subsequent six months. In addition to GLP-1 receptor agonists, SGLT2 inhibitors may be a potential approach for the management of DM in PWS, especially in young patients whose pancreatic insulin secretion capabilities are still preserved.

Protein Arginine N-methyltransferases 5 and 7 Promote HIV-1 Production.

Current therapies for human immunodeficiency virus type 1 (HIV-1) do not completely eliminate viral reservoirs in cells, such as macrophages. The HIV-1 accessory protein viral protein R (Vpr) promotes virus production in macrophages, and the maintenance of Vpr is essential for HIV-1 replication in these reservoir cells. We identified two novel Vpr-binding proteins, i.e., protein arginine N-methyltransferases (PRMTs) 5 and 7, using human monocyte-derived macrophages (MDMs). Both proteins found to be important for prevention of Vpr degradation by the proteasome; in the context of PRMT5 and PRMT7 knockdowns, degradation of Vpr could be prevented using a proteasome inhibitor. In MDMs infected with a wild-type strain, knockdown of PRMT5/PRMT7 and low expression of PRMT5 resulted in inefficient virus production like Vpr-deficient strain infections. Thus, our findings suggest that PRMT5 and PRMT7 support HIV-1 replication via maintenance of Vpr protein stability.