Abstract
The current COVID-19 pandemic is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We demonstrate that despite the large size of the viral RNA genome (~30 kb), ...infectious full-length cDNA is readily assembled in vitro by a circular polymerase extension reaction (CPER) methodology without the need for technically demanding intermediate steps. Overlapping cDNA fragments are generated from viral RNA and assembled together with a linker fragment containing CMV promoter into a circular full-length viral cDNA in a single reaction. Transfection of the circular cDNA into mammalian cells results in the recovery of infectious SARS-CoV-2 virus that exhibits properties comparable to the parental virus in vitro and in vivo. CPER is also used to generate insect-specific Casuarina virus with ~20 kb genome and the human pathogens Ross River virus (Alphavirus) and Norovirus (Calicivirus), with the latter from a clinical sample. Additionally, reporter and mutant viruses are generated and employed to study virus replication and virus-receptor interactions.
NF-κB2/p100 (p100) is an inhibitor of κB (IκB) protein that is partially degraded to produce the NF-κB2/p52 (p52) transcription factor. Heterozygous NFKB2 mutations cause a human syndrome of ...immunodeficiency and autoimmunity, but whether autoimmunity arises from insufficiency of p52 or IκB function of mutated p100 is unclear. Here, we studied mice bearing mutations in the p100 degron, a domain that harbors most of the clinically recognized mutations and is required for signal-dependent p100 degradation. Distinct mutations caused graded increases in p100-degradation resistance. Severe p100-degradation resistance, due to inheritance of one highly degradation-resistant allele or two subclinical alleles, caused thymic medullary hypoplasia and autoimmune disease, whereas the absence of p100 and p52 did not. We inferred a similar mechanism occurs in humans, as the T cell receptor repertoires of affected humans and mice contained a hydrophobic signature of increased self-reactivity. Autoimmunity in autosomal dominant NFKB2 syndrome arises largely from defects in nonhematopoietic cells caused by the IκB function of degradation-resistant p100.
Introduction
Alzheimer's disease (AD) and age-related eye diseases pose an increasing burden as the world's population ages. However, there is limited understanding on the association of AD/cognitive ...impairment, no dementia (CIND) with age-related eye diseases.
Methods
In this cross-sectional, memory clinic-based study of multiethnic Asians aged 50 and above, participants were diagnosed as AD (
n
= 216), cognitive impairment, no dementia (CIND) (
n
= 252), and no cognitive impairment (NCI) (
n
= 124) according to internationally accepted criteria. Retinal photographs were graded for the presence of age-related macular degeneration (AMD) and diabetic retinopathy (DR) using standard grading systems. Multivariable-adjusted logistic regression models were used to determine the associations between neurological diagnosis and odds of having eye diseases.
Results
Over half of the adults had at least one eye disease, with AMD being the most common (60.1%;
n
= 356), followed by DR (8.4%;
n
= 50). After controlling for age, sex, race, educational level, and marital status, persons with AD were more likely to have moderate DR or worse (OR = 2.95, 95% CI = 1.15–7.60) compared with NCI. In the fully adjusted model, the neurological diagnosis was not associated with AMD (OR = 0.75, 95% CI = 0.45–1.24).
Conclusion
Patients with AD have an increased odds of having moderate DR or worse, which suggests that these vulnerable individuals may benefit from specific social support and screening for eye diseases.
Histone methyltransferases (HMTs) are crucial in gene regulation and function, yet their role in natural killer (NK) cell biology within the tumor microenvironment (TME) remains largely unknown. We ...demonstrate that the HMT DOT1L limits NK cell conversion to CD49a+ CD49b+ intILC1, a subset that can be observed in the TME in response to stimulation with transforming growth factor (TGF)-β and is correlated with impaired tumor control. Deleting Dot1l in NKp46-expressing cells reveals its pivotal role in maintaining NK cell phenotype and function. Loss of DOT1L skews NK cells toward intILC1s even in the absence of TGF-β. Transcriptionally, DOT1L-null NK cells closely resemble intILC1s and ILC1s, correlating with altered NK cell responses and impaired solid tumor control. These findings deepen our understanding of NK cell biology and could inform approaches to prevent NK cell conversion to intILC1s in adoptive NK cell therapies for cancer.
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•DOT1L maintains a core transcriptional program defining NK cell phenotype and function•DOT1L impairs NK cell to intILC1/ILC1 phenotype conversion independent of TGF-β•Conditional DOT1L knockout mice display decreased tumor control
Sudholz et al. identify DOT1L as a key regulator of NK cell phenotype and function. DOT1L-deficient NK cells exhibit an enhanced intILC1/ILC1 phenotype, irrespective of TGF-β. Conditional DOT1L knockout mice display decreased tumor control. We conclude that DOT1L may support MEF2C expression, which allows optimal NK cell phenotype and function.
ABSTRACT
Objective
Class III obesity (body mass index BMI ≥ 40 kg m−2) significantly impairs the immune response to SARS‐CoV‐2 vaccination. However, the effect of an elevated BMI (≥ 25 kg m−2) on ...humoral immunity to SARS‐CoV‐2 infection and COVID‐19 vaccination remains unclear.
Methods
We collected blood samples from people who recovered from SARS‐CoV‐2 infection approximately 3 and 13 months of post‐infection (noting that these individuals were not exposed to SARS‐CoV‐2 or vaccinated in the interim). We also collected blood samples from people approximately 5 months of post‐second dose COVID‐19 vaccination (the majority of whom did not have a prior SARS‐CoV‐2 infection). We measured their humoral responses to SARS‐CoV‐2, grouping individuals based on a BMI greater or less than 25 kg m−2.
Results
Here, we show that an increased BMI (≥ 25 kg m−2), when accounting for age and sex differences, is associated with reduced antibody responses after SARS‐CoV‐2 infection. At 3 months of post‐infection, an elevated BMI was associated with reduced antibody titres. At 13 months of post‐infection, an elevated BMI was associated with reduced antibody avidity and a reduced percentage of spike‐positive B cells. In contrast, no significant association was noted between a BMI ≥ 25 kg m−2 and humoral immunity to SARS‐CoV‐2 at 5 months of post‐secondary vaccination.
Conclusions
Taken together, these data showed that elevated BMI is associated with an impaired humoral immune response to SARS‐CoV‐2 infection. The impairment of infection‐induced immunity in individuals with a BMI ≥ 25 kg m−2 suggests an added impetus for vaccination rather than relying on infection‐induced immunity.
In this study, we found decreased humoral immunity to SARS‐CoV‐2 infection in individuals with an elevated body mass index (BMI). In contrast, there was no association between increased BMI and the humoral immune response to SARS‐CoV‐2 vaccination.
Inflammation is a hallmark mechanism of ischemic stroke-induced brain injury. Recent studies have shown that an intracellular multimeric protein complex known as an inflammasome is a key factor for ...inducing an inflammatory response, and apoptotic and pyroptotic cell death in ischemic stroke. Inflammasome assembly leads to the activation of pro-inflammatory caspases, and the maturation and secretion of pro-inflammatory cytokines IL-1β and IL-18. While the role of inflammasomes in ischemic stroke-induced neuronal death, and microglial activation and cell death have been established, little is known about the role of inflammasomes in astrocytes under ischemic conditions. In this study, we investigated the expression and activation of inflammasome components in protoplasmic and fibrous astrocytes under ischemic conditions. We found that both protoplasmic and fibrous astrocytes expressed a differential increase in inflammasome protein components, and that their activation promoted maturation of IL-1β and IL-18, and secretion of IL-1β, as well as initiating apoptotic and pyroptotic cell death. Pharmacological inhibition of caspase-1 decreased expression of cleaved caspase-1 and production of mature IL-1β, and protected against inflammasome-mediated apoptotic and pyroptotic cell death. Overall, this study provides novel insights into the role of inflammasome signaling in astrocytes under ischemic conditions.
Accurate and reliable drug susceptibility testing (DST) is essential for the effective treatment and control of tuberculosis. With the increase in drug-resistant organisms, newer and less ...conventional antimicrobial agents are used for treatment. Recently, we found an unprecedented rise in the number of clofazimine-resistant Mycobacterium tuberculosis isolates in our laboratory. An investigation found that this phenomenon was due to a change in the method of drug preparation. We performed studies to assess the impact of water and dimethyl sulfoxide (DMSO) as a final diluent for clofazimine drug testing. Based on our findings, the use of DMSO as a solvent for M. tuberculosis DST was optimised using the BACTEC MGIT 960 platform.
Background: Vascular dementia (VaD) is occasionally caused by a single, strategically located stroke. In this report, we describe the clinical and anatomical features of 12 cases of strategic single ...infarct dementia (SSID) from Singapore.
Methods: Each patient completed a standardized diagnostic evaluation including history, neurological and neuropsychological examination, laboratory testing, and brain imaging. Dementia was diagnosed using the
Diagnostic and Statistical Manual, 3rd edition, revised (DSM-III-R) criteria, and VaD was diagnosed using the National Institute of Neurologic Disorders and Stroke and the Association Internationale pour la Recherche et l'Enseignement en Neurosciences (NINDS–AIREN) criteria. VaD patients whose brain imaging study revealed a single cerebrovascular event were diagnosed with SSID.
Results: We identified 12 cases of SSID among 125 VaD patients (9.6%). Stroke mechanism was lacunar infarction in five cases, embolism in four cases, large vessel thrombosis in two cases, and parenchymal hemorrhage in one case. The most commonly impaired cognitive domains on neuropsychological testing were visual memory, visuoconstruction, and language. In 11 of the 12 SSID cases, the stroke was located in the left hemisphere. The thalamus, either alone or as the proximal portion of a posterior cerebral artery infarction, was involved in 8 of the 12 cases. Stroke locations in the nonthalamic SSID cases included left angular gyrus, subcortical left frontal lobe including minor forceps, left basal forebrain and medial frontal lobe plus anterior corpus callosum (proximal anterior cerebral artery infarction), and anterior corpus callosum alone.
Conclusions: Various stroke mechanisms may produce SSID. In our SSID cases, vascular damage almost always involved the left hemisphere and frequently involved the thalamus and major interhemispheric or intrahemispheric white matter pathways.
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