The DMT1 isoform lacking the iron‐response element regulates normal and malignant hematopoiesis via NOTCH pathway activation

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The DMT1 isoform lacking the iron-response element regulates normal and malignant hematopoiesis via NOTCH pathway activation

The authors find that, in normal hematopoiesis, the DMT1/SLC11A2 nonIRE isoform controls the hematopoietic stem cell pool by dictating differentiation of the myeloid and B cell lymphoid lineages while suppressing the production of platelets via Notch/Myc pathway regulation. In TLX1-defective leukemia, DMT1 nonIRE boosts NOTCH pathway activity, known to be responsible for unlimited proliferation of leukemic cells.


Natural resistance-associated macrophage protein 2 (NRAMP 2; also known as DMT1 and encoded by SLC11A2) is mainly known for its iron transport activity. Recently, the DMT1 isoform lacking the iron-response element (nonIRE) was associated with aberrant NOTCH pathway activity. In this report, we investigated the function of DMT1 nonIRE in normal and malignant hematopoiesis. Knockdown of Dmt1 nonIRE in mice showed that it has non-canonical functions in hematopoietic stem cell differentiation: its knockdown suppressed development along the myeloid and lymphoid lineages, while promoting the production of platelets. These phenotypic effects on the hematopoietic system induced by Dmt1 nonIRE knockdown were linked to suppression of Notch/Myc pathway activity. Conversely, our data indicate a non-canonical function for DMT1 nonIRE overexpression in boosting NOTCH pathway activity in T-cell leukemia homeobox protein 1 (TLX1)-defective leukemia. This work sets the stage for future investigation using a multiple-hit T-cell acute lymphoblastic leukemia (T-ALL) model to further investigate the function of DMT1 nonIRE in T-ALL disease development and progression.

OTUD6A orchestrates complex modulation of TEAD4‐mediated transcriptional programs

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OTUD6A orchestrates complex modulation of TEAD4-mediated transcriptional programs

The deubiquitinating enzyme OTUD6A deubiquitinates the TEAD4 transcription factor, enhancing its interaction with co-activator YAP over co-repressor VGLL4. This modulation promotes TEAD4 transcriptional activity, facilitating the expression of multiple target genes controlled by the YAP-TEAD complex.


TEAD transcription factors play a central role in the Hippo signaling pathway. In this study, we focused on transcriptional enhancer factor TEF-3 (TEAD4), exploring its regulation by the deubiquitinase OTU domain-containing protein 6A (OTUD6A). We identified OTUD6A as a TEAD4-interacting deubiquitinase, positively influencing TEAD-driven transcription without altering TEAD4 stability. Structural analyses revealed specific interaction domains: the N-terminal domain of OTUD6A and the YAP-binding domain of TEAD4. Functional assays demonstrated the positive impact of OTUD6A on the transcription of YAP–TEAD target genes. Despite no impact on TEAD4 nuclear localization, OTUD6A selectively modulated nuclear interactions, enhancing YAP–TEAD4 complex formation while suppressing VGLL4 (transcription cofactor vestigial-like protein 4)–TEAD4 interaction. Critically, OTUD6A facilitated YAP–TEAD4 complex binding to target gene promoters. Our study unveils the regulatory landscape of OTUD6A on TEAD4, providing insights into diseases regulated by YAP–TEAD complexes.

Hepatitis B virus‐specific human stem cell memory T cells differentiate into cytotoxic T cells and eradicate HBV‐infected hepatocytes in mice

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Hepatitis B virus-specific human stem cell memory T cells differentiate into cytotoxic T cells and eradicate HBV-infected hepatocytes in mice

Here, we detected stem cell memory T cells (TSCMs) in chronic hepatitis B virus (HBV)-infected patients, using HBV core and polymerase peptide HLA tetramers. When these TSCMs were transferred into the human hepatocyte-transplanted, HBV-infected TK-NOG mouse, they differentiated into cytotoxic T lymphocytes, produced interferon gamma and interleukin-2, and developed histologically proven hepatitis. Furthermore, HBV DNA and human albumin in mouse serum declined and human hepatocytes were eliminated in the mouse model.


Chronic infection with the hepatitis B virus (HBV) induces progressive hepatic impairment. Achieving complete eradication of the virus remains a formidable challenge. Cytotoxic T lymphocytes, specific to viral antigens, either exhibit a numerical deficiency or succumb to an exhausted state in individuals chronically afflicted with HBV. The comprehension of the genesis and dissemination of stem cell memory T cells (TSCMs) targeting HBV remains inadequately elucidated. We identified TSCMs in subjects with chronic HBV infection and scrutinized their efficacy in a murine model with human hepatocyte transplants, specifically the TK-NOG mice. TSCMs were discerned in all subjects under examination. Introduction of TSCMs into the HBV mouse model precipitated a severe necro-inflammatory response, resulting in the elimination of human hepatocytes. TSCMs may constitute a valuable tool in the pursuit of a remedial therapy for HBV infection.

Presence of immunoglobulin E‐expressing antibody‐secreting cells in the dermis close to bullous pemphigoid lesions

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Abstract

Antibody-secreting cells (ASCs) produce immunoglobulin (Ig) G and IgE autoantibodies in secondary lymphoid organs. Evidence also suggests their existence in the skin in various chronic inflammatory conditions, and in association with CXCL12 and CXCL13, they regulate the recruitment/survival of ASCs and germinal center formation to generate ASCs, respectively. However, the presence of IgG and IgE in bullous pemphigoid (BP) lesions needs to be addressed. Here, we aimed to analyse BP skin for the presence of IgG and IgE and the factors contributing to their generation, recruitment, and persistence. Skin samples from 30 patients with BP were stained to identify ASCs and the immunoglobulin type they expressed. The presence of tertiary lymphoid organ (TLO) elements, which generate ASCs in non-lymphoid tissues, and the chemokines CXCL12 and CXCL13, which regulate the migration/persistence of ASCs in lymphoid tissues and formation of TLOs, respectively, were evaluated in BP skin. BP skin harboured ASCs expressing the two types of antibodies IgG and IgE. ASCs were found in high-grade cellular aggregates containing TLO elements: T cells, B cells, CXCL12+ cells, CXCL13+ cells and high endothelial venules. IgG+ ASCs were detected among these aggregates, whereas IgE+ ASCs were dispersed throughout the dermis. CXCL12+ fibroblast-like cells were located close to ASCs. The inflammatory microenvironment of BP lesions may contribute to the antibody load characteristic of the skin of patients with BP by providing a site for the presence of ASCs. CXCL13 and CXCL12 expression may contribute to the generation and recruitment/survival of ASCs, respectively.

Genetic investigations on backfat thickness and body condition score in German Holstein cattle

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Abstract

Up to now, little has been known about backfat thickness (BFT) in dairy cattle. The objective of this study was to investigate the lactation curve and genetic parameters for BFT as well as its relationship with body condition score (BCS) and milk yield (MKG). For this purpose, a dataset was analysed including phenotypic observations of 1929 German Holstein cows for BFT, BCS and MKG recorded on a single research dairy farm between September 2005 and December 2022. Additionally, pedigree and genomic information was available. Lactation curves were predicted and genetic parameters were estimated for all traits in first to third lactation using univariate random regression models. For BCS, lactation curves had nadirs at 94 DIM, 101 DIM and 107 DIM in first, second and third lactation. By contrast, trajectories of BFT showed lowest values later in lactation at 129 DIM, 117 DIM and 120 DIM in lactation numbers 1 to 3, respectively. Although lactation curves of BCS and BFT had similar shapes, the traits showed distinct sequence of curves for lactation number 2 and 3. Cows in third lactation had highest BCS, whereas highest BFT values were found for second parity animals. Average heritabilities were 0.315 ± 0.052, 0.297 ± 0.048 and 0.332 ± 0.061 for BCS in lactation number 1 to 3, respectively. Compared to that, BFT had considerably higher heritability in all lactation numbers with estimates ranging between 0.357 ± 0.028 and 0.424 ± 0.034. Pearson correlation coefficients between estimated breeding values for the 3 traits were negative between MKG with both BCS (r = −0.245 to −0.322) and BFT (r = −0.163 to −0.301). Correlation between traits BCS and BFT was positive and consistently high (r = 0.719 to 0.738). Overall, the results of this study suggest that BFT and BCS show genetic differences in dairy cattle, which might be due to differences in depletion and accumulation of body reserves measured by BFT and BCS. Therefore, routine recording of BFT on practical dairy farms could provide valuable information beyond BCS measurements and might be useful, for example, to better assess the nutritional status of cows.

Structural determinants for membrane binding of the EGFR juxtamembrane domain

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Structural determinants for membrane binding of the EGFR juxtamembrane domain

The region containing residues I649 − L659 of the epidermal growth factor receptor (EGFR) juxtamembrane domain (JM) specifically interacts with PI(4,5)P2-or phosphatidylserine-containing membranes, suggesting that membrane binding may affect JM dimerization and, therefore, regulate EGFR kinase activation.


Overactivation of the epidermal growth factor receptor (EGFR) is critical for the development of multiple cancers. Previous studies have shown that the cell membrane is a key regulator of EGFR kinase activity through its interaction with the EGFR juxtamembrane domain (JM). However, the lipid recognition specificity of EGFR-JM and its interaction details remain unclear. Using lipid strip and liposome pulldown assays, we showed that EGFR-JM could specifically interact with PI(4,5)P2-or phosphatidylserine-containing membranes. We further characterized the JM–membrane interaction using NMR-titration-based chemical shift perturbation and paramagnetic relaxation enhancement analyses, and found that residues I649 − L659 comprised the membrane-binding site. Furthermore, the membrane-binding region contains the predicted dimerization motif of JM, 655LRRLL659, suggesting that membrane binding may affect JM dimerization and, therefore, regulate kinase activation.

The positive allosteric modulator BPAM344 and L‐glutamate introduce an active‐like structure of the ligand‐binding domain of GluK2

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The positive allosteric modulator BPAM344 and L-glutamate introduce an active-like structure of the ligand-binding domain of GluK2

X-ray crystallography was used to determine an active-like dimer of the ligand-binding domain of GluK2, locating the positive allosteric modulator BPAM344 within the dimeric interface. Selected residues T535 and Q786 differing between GluK2 and GluA2 were investigated with calcium-sensitive fluorescence-based assays on transiently transfected cells. A three-fold increase in BPAM344 potency occurred with the double mutant T535S-Q786S in GluK2(Q).


Kainate receptors belong to the family of ionotropic glutamate receptors and contribute to the majority of fast excitatory neurotransmission. Consequently, they also play a role in brain diseases. Therefore, understanding how these receptors can be modulated is of importance. Our study provides a crystal structure of the dimeric ligand-binding domain of the kainate receptor GluK2 in complex with L-glutamate and the small-molecule positive allosteric modulator, BPAM344, in an active-like conformation. The role of Thr535 and Gln786 in modulating GluK2 by BPAM344 was investigated using a calcium-sensitive fluorescence-based assay on transiently transfected cells expressing GluK2 and mutants hereof. This study may aid in the design of compounds targeting kainate receptors, expanding their potential as targets for the treatment of brain diseases.

EU‐LIFE charter of independent life science research institutes

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EU-LIFE charter of independent life science research institutes

In the EU-LIFE Charter of Independent Life Science Research Institutes, we are detailing 10 principles that are essential to enable institutes to foster excellence in research. The parameters to optimize and strive for range from enabling highest quality work to safeguarding independence and allowing engagement with society. Clearly communicating the core principles defines the roles and responsibility of institutes and allows their uncompromised commitment to excellence. This image was created with the assistance of DALL·E 2.


The diverse range of organizations contributing to the global research ecosystem is believed to enhance the overall quality and resilience of its output. Mid-sized autonomous research institutes, distinct from universities, play a crucial role in this landscape. They often lead the way in new research fields and experimental methods, including those in social and organizational domains, which are vital for driving innovation. The EU-LIFE alliance was established with the goal of fostering excellence by developing and disseminating best practices among European biomedical research institutes. As directors of the 15 EU-LIFE institutes, we have spent a decade comparing and refining our processes. Now, we are eager to share the insights we've gained. To this end, we have crafted this Charter, outlining 10 principles we deem essential for research institutes to flourish and achieve ground-breaking discoveries. These principles, detailed in the Charter, encompass excellence, independence, training, internationality and inclusivity, mission focus, technological advancement, administrative innovation, cooperation, societal impact, and public engagement. Our aim is to inspire the establishment of new institutes that adhere to these principles and to raise awareness about their significance. We are convinced that they should be viewed a crucial component of any national and international innovation strategies.