Frequency and prognostic implications of KMT2A rearrangements in children with precursor B-cell lymphoma

Our analysis is limited regarding to the molecular features of BCP-L, since pediatric BCP-L is rare compared to BCP-ALL, and we were limited to archival BCP-L tissue that were small and preserved in FFPE blocks. Nevertheless, our data suggest that BCP-L is a valuable model for studying pathogenic mechanisms of BCP neoplasms, especially those with KMT2A aberrations. Detailed molecular genetic analysis will be required to understand which mechanisms lead to the clinical presentation as lymphoma instead of leukemia, and whether this clinical presentation is driven by genetic features of the tumor, or host dependent factors such as immunological status

Epigenetic Silencing of Tumor Suppressor lncRNA <i>NKILA</i>: Implication on NF-κB Signaling in Non-Hodgkin’s Lymphoma

The long non-coding RNA (lncRNA) NKILA, localized to 20q13.31, is a negative regulator of NF-κB signaling implicated in carcinogenesis. As a CpG island is embedded in the promoter region of NKILA, it is hypothesized as a tumor suppressor lncRNA silenced by promoter DNA methylation in non-Hodgkin’s lymphoma (NHL). By pyrosequencing-verified methylation-specific PCR, NKILA methylation was detected in 1/10 (10%) NHL cell lines, but not in normal peripheral blood buffy coats or tonsils. NKILA methylation correlated with the repression of NKILA in cell lines. Hypomethylation treatment with 5-Aza-2′-deoxycytidine resulted in promoter demethylation and the re-expression of NKILA. In 102 NHL primary samples, NKILA was methylated in 29 (51.79%) diffuse large B-cell lymphoma (DLBCL) and 4 (20%) peripheral T-cell lymphoma cases, but unmethylated in all 26 mantle cell lymphoma cases. Mechanistically, the knockdown of NKILA resulted in promoting IkBα phosphorylation, associated with nucleus translocation of total p65 and phosphorylated p65 in SU-DHL-1 cells, hence constitutive NF-κB activation. Functionally, the knockdown of NKILA in SU-DHL-1 cells led to decreased cell death and increased cellular proliferation. Collectively, NKILA was a tumor suppressor lncRNA frequently hypermethylated in DLBCL. Promoter DNA methylation-mediated NKILA silencing resulted in increased cellular proliferation and decreased cell death via the repression of NF-κB signaling in NHL

SARS-CoV-2 infection activates inflammatory macrophages in vascular immune organoids

Abstract SARS-CoV-2 provokes devastating tissue damage by cytokine release syndrome and leads to multi-organ failure. Modeling the process of immune cell activation and subsequent tissue damage is a significant task. Organoids from human tissues advanced our understanding of SARS-CoV-2 infection mechanisms though, they are missing crucial components: immune cells and endothelial cells. This study aims to generate organoids with these components. We established vascular immune organoids from human pluripotent stem cells and examined the effect of SARS-CoV-2 infection. We demonstrated that infections activated inflammatory macrophages. Notably, the upregulation of interferon signaling supports macrophages’ role in cytokine release syndrome. We propose vascular immune organoids are a useful platform to model and discover factors that ameliorate SARS-CoV-2-mediated cytokine release syndrome

Mp1p Is a Virulence Factor in <i>Talaromyces (Penicillium) marneffei</i>

<div><p>Background</p><p><i>Talaromyces marneffei</i> is an opportunistic dimorphic fungus prevalent in Southeast Asia. We previously demonstrated that Mp1p is an immunogenic surface and secretory mannoprotein of <i>T</i>. <i>marneffei</i>. Since Mp1p is a surface protein that can generate protective immunity, we hypothesized that Mp1p and/or its homologs are virulence factors.</p><p>Methodology/Principal Findings</p><p>We examined the pathogenic roles of Mp1p and its homologs in a mouse model. All mice died 21 and 30 days after challenge with wild-type <i>T</i>. <i>marneffei</i> PM1 and <i>MP1</i> complemented mutant respectively. None of the mice died 60 days after challenge with <i>MP1</i> knockout mutant (P<0.0001). Seventy percent of mice died 60 days after challenge with <i>MP1</i> knockdown mutant (P<0.0001). All mice died after challenge with <i>MPLP1</i> to <i>MPLP13</i> knockdown mutants, suggesting that only Mp1p plays a significant role in virulence. The mean fungal loads of PM1 and <i>MP1</i> complemented mutant in the liver, lung, kidney and spleen were significantly higher than those of the <i>MP1</i> knockout mutant. Similarly, the mean load of PM1 in the liver, lung and spleen were significantly higher than that of the <i>MP1</i> knockdown mutant. Histopathological studies showed an abundance of yeast in the kidney, spleen, liver and lung with more marked hepatic and splenic necrosis in mice challenged with PM1 compared to <i>MP1</i> knockout and <i>MP1</i> knockdown mutants. Likewise, a higher abundance of yeast was observed in the liver and spleen of mice challenged with <i>MP1</i> complemented mutant compared to <i>MP1</i> knockout mutant. PM1 and <i>MP1</i> complemented mutant survived significantly better than <i>MP1</i> knockout mutant in macrophages at 48 hours (P<0.01) post-infection. The mean fungal counts of <i>Pichia pastoris</i> GS115-<i>MP1</i> in the liver (P<0.001) and spleen (P<0.05) of mice were significantly higher than those of GS115 at 24 hours post-challenge.</p><p>Conclusions/Significance</p><p>Mp1p is a key virulence factor of <i>T</i>. <i>marneffei</i>. Mp1p mediates virulence by improving the survival of <i>T</i>. <i>marneffei</i> in macrophages.</p></div

Mp1p is a virulence factor of <i>T</i>. <i>marneffei</i>.

<p>(A) Survival curves of Balb/c mice challenged with <i>T</i>. <i>marneffei</i> PM1, <i>MP1</i> knockout mutant, <i>MP1</i> complemented mutant and knockdown mutants (***P<0.0001). (B) Mean fungal burden in spleen, kidney, liver and lung of mice challenged with <i>T</i>. <i>marneffei</i> PM1, <i>MP1</i> knockout mutant, <i>MP1</i> complemented mutant and <i>MP1</i> knockdown mutant at day 12 post-challenge (***P<0.001, **P<0.01, *P<0.05). Error bars represent standard deviations. (C) Histopathological examination of PAS stained internal organs of mice at day 12 post-challenge. <i>T</i>. <i>marneffei</i> yeast cells are shown in black arrows and tissue necrosis in blue arrows.</p

Phylogenetic analysis of the putative LBD of Mp1p homologs in <i>T</i>. <i>marneffei</i> and orthologs in other fungi.

<p>Homologs of Mp1p in <i>T</i>. <i>marneffei</i> are shown in bold. The tree was constructed by maximum likelihood method with bootstrap values calculated from 1,000 trees and rooted on midpoint. The scale bar indicates the branch lengths that correspond to 0.5 substitutions per site as indicated. Names and accession numbers are given as cited in the GenBank database.</p

Fungal strains used in this study

<p>Fungal strains used in this study</p