@article {1009, title = {GIMAP5 maintains liver endothelial cell homeostasis and prevents portal hypertension.}, journal = {J Exp Med}, volume = {218}, year = {2021}, month = {2021 Jul 05}, abstract = {

Portal hypertension is a major contributor to decompensation and death from liver disease, a global health problem. Here, we demonstrate homozygous damaging mutations in GIMAP5, a small organellar GTPase, in four families with unexplained portal hypertension. We show that GIMAP5 is expressed in hepatic endothelial cells and that its loss in both humans and mice results in capillarization of liver sinusoidal endothelial cells (LSECs); this effect is also seen when GIMAP5 is selectively deleted in endothelial cells. Single-cell RNA-sequencing analysis in a GIMAP5-deficient mouse model reveals replacement of LSECs with capillarized endothelial cells, a reduction of macrovascular hepatic endothelial cells, and places GIMAP5 upstream of GATA4, a transcription factor required for LSEC specification. Thus, GIMAP5 is a critical regulator of liver endothelial cell homeostasis and, when absent, produces portal hypertension. These findings provide new insight into the pathogenesis of portal hypertension, a major contributor to morbidity and mortality from liver disease.

}, issn = {1540-9538}, doi = {10.1084/jem.20201745}, author = {Drzewiecki, Kaela and Choi, Jungmin and Brancale, Joseph and Leney-Greene, Michael A and Sari, Sinan and Dalgi{\c c}, Buket and {\"U}nl{\"u}soy Aksu, Aysel and Evirgen {\c S}ahin, G{\"u}lseren and Ozen, Ahmet and Baris, Safa and Karakoc-Aydiner, Elif and Jain, Dhanpat and Kleiner, David and Schmalz, Michael and Radhakrishnan, Kadakkal and Zhang, Junhui and Hoebe, Kasper and Su, Helen C and Pereira, Jo{\~a}o P and Lenardo, Michael J and Lifton, Richard P and Vilarinho, S{\'\i}lvia} } @article {771, title = {Defective glycosylation and multisystem abnormalities characterize the primary immunodeficiency XMEN disease.}, journal = {J Clin Invest}, volume = {130}, year = {2020}, month = {2020 01 02}, pages = {507-522}, abstract = {

X-linked immunodeficiency with magnesium defect, EBV infection, and neoplasia (XMEN) disease are caused by deficiency of the magnesium transporter 1 (MAGT1) gene. We studied 23 patients with XMEN, 8 of whom were EBV naive. We observed lymphadenopathy (LAD), cytopenias, liver disease, cavum septum pellucidum (CSP), and increased CD4-CD8-B220-TCRαβ+ T cells (αβDNTs), in addition to the previously described features of an inverted CD4/CD8 ratio, CD4+ T lymphocytopenia, increased B cells, dysgammaglobulinemia, and decreased expression of the natural killer group 2, member D (NKG2D) receptor. EBV-associated B cell malignancies occurred frequently in EBV-infected patients. We studied patients with XMEN and patients with autoimmune lymphoproliferative syndrome (ALPS) by deep immunophenotyping (32 immune markers) using time-of-flight mass cytometry (CyTOF). Our analysis revealed that the abundance of 2 populations of naive B cells (CD20+CD27-CD22+IgM+HLA-DR+CXCR5+CXCR4++CD10+CD38+ and CD20+CD27-CD22+IgM+HLA-DR+CXCR5+CXCR4+CD10-CD38-) could differentially classify XMEN, ALPS, and healthy individuals. We also performed glycoproteomics analysis on T lymphocytes and show that XMEN disease is a congenital disorder of glycosylation that affects a restricted subset of glycoproteins. Transfection of MAGT1 mRNA enabled us to rescue proteins with defective glycosylation. Together, these data provide new clinical and pathophysiological foundations with important ramifications for the diagnosis and treatment of XMEN disease.

}, keywords = {Antigens, CD, Autoimmune Lymphoproliferative Syndrome, Cation Transport Proteins, CD4-CD8 Ratio, Female, Glycosylation, Humans, Magnesium Deficiency, Male, X-Linked Combined Immunodeficiency Diseases}, issn = {1558-8238}, doi = {10.1172/JCI131116}, author = {Ravell, Juan C and Matsuda-Lennikov, Mami and Chauvin, Samuel D and Zou, Juan and Biancalana, Matthew and Deeb, Sally J and Price, Susan and Su, Helen C and Notarangelo, Giulia and Jiang, Ping and Morawski, Aaron and Kanellopoulou, Chrysi and Binder, Kyle and Mukherjee, Ratnadeep and Anibal, James T and Sellers, Brian and Zheng, Lixin and He, Tingyan and George, Alex B and Pittaluga, Stefania and Powers, Astin and Kleiner, David E and Kapuria, Devika and Ghany, Marc and Hunsberger, Sally and Cohen, Jeffrey I and Uzel, Gulbu and Bergerson, Jenna and Wolfe, Lynne and Toro, Camilo and Gahl, William and Folio, Les R and Matthews, Helen and Angelus, Pam and Chinn, Ivan K and Orange, Jordan S and Trujillo-Vargas, Claudia M and Franco, Jose Luis and Orrego-Arango, Julio and Guti{\'e}rrez-Hincapi{\'e}, Sebastian and Patel, Niraj Chandrakant and Raymond, Kimiyo and Patiroglu, Turkan and Unal, Ekrem and Karakukcu, Musa and Day, Alexandre Gr and Mehta, Pankaj and Masutani, Evan and De Ravin, Suk S and Malech, Harry L and Altan-Bonnet, Gr{\'e}goire and Rao, V Koneti and Mann, Matthias and Lenardo, Michael J} } @article {818, title = {HEM1 deficiency disrupts mTORC2 and F-actin control in inherited immunodysregulatory disease.}, journal = {Science}, volume = {369}, year = {2020}, month = {2020 07 10}, pages = {202-207}, abstract = {

Immunodeficiency often coincides with hyperactive immune disorders such as autoimmunity, lymphoproliferation, or atopy, but this coincidence is rarely understood on a molecular level. We describe five patients from four families with immunodeficiency coupled with atopy, lymphoproliferation, and cytokine overproduction harboring mutations in , which encodes the hematopoietic-specific HEM1 protein. These mutations cause the loss of the HEM1 protein and the WAVE regulatory complex (WRC) or disrupt binding to the WRC regulator, Arf1, thereby impairing actin polymerization, synapse formation, and immune cell migration. Diminished cortical actin networks caused by WRC loss led to uncontrolled cytokine release and immune hyperresponsiveness. HEM1 loss also blocked mechanistic target of rapamycin complex 2 (mTORC2)-dependent AKT phosphorylation, T cell proliferation, and selected effector functions, leading to immunodeficiency. Thus, the evolutionarily conserved HEM1 protein simultaneously regulates filamentous actin (F-actin) and mTORC2 signaling to achieve equipoise in immune responses.

}, keywords = {Actins, ADP-Ribosylation Factor 1, CD4-Positive T-Lymphocytes, Cell Proliferation, Cytokines, Humans, Immunologic Deficiency Syndromes, Lymphoproliferative Disorders, Mechanistic Target of Rapamycin Complex 2, Membrane Proteins, Pedigree, Phosphorylation, Wiskott-Aldrich Syndrome Protein Family}, issn = {1095-9203}, doi = {10.1126/science.aay5663}, author = {Cook, Sarah A and Comrie, William A and Poli, M Cecilia and Similuk, Morgan and Oler, Andrew J and Faruqi, Aiman J and Kuhns, Douglas B and Yang, Sheng and Vargas-Hernandez, Alexander and Carisey, Alexandre F and Fournier, Benjamin and Anderson, D Eric and Price, Susan and Smelkinson, Margery and Abou Chahla, Wadih and Forbes, Lisa R and Mace, Emily M and Cao, Tram N and Coban-Akdemir, Zeynep H and Jhangiani, Shalini N and Muzny, Donna M and Gibbs, Richard A and Lupski, James R and Orange, Jordan S and Cuvelier, Geoffrey D E and Al Hassani, Moza and Al Kaabi, Nawal and Al Yafei, Zain and Jyonouchi, Soma and Raje, Nikita and Caldwell, Jason W and Huang, Yanping and Burkhardt, Janis K and Latour, Sylvain and Chen, Baoyu and ElGhazali, Gehad and Rao, V Koneti and Chinn, Ivan K and Lenardo, Michael J} }