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Background: An increasing number of infected children are being encountered with the rapid spread of COVID-19, yet the vulnerability of children with COVID-19 i

Iron overload-induced cardiovascular toxicity is one of the most common causes of morbidity and mortality in beta-thalassemia major patients. We have previously shown that iron overload-induced systemic arterial changes characterized by endothelial dysfunction are associated with increased endothelial microparticle (EMP) release. In this study, we further demonstrate how EMP release is associated with iron-induced mitochondrial injury and apoptosis of endothelial cells. Iron increased the production of reactive oxygen species (ROS) and calcium influx into mitochondria [Ca2+]m. Iron also disturbed mitochondrial respiration function and eventually led to loss of mitochondrial membrane potential (ΔΨm). A significant increase in apoptotic cells and EMPs were found under iron treatment. EMPs contained tissue factor (TF), which has potential clinical impact on thromboembolic phenomenon. Then, we investigated the salvaging effect of deferiprone (L1) on endothelial cell damage and EMP release. We found that L1 could inhibit iron-induced ROS generation, and decrease mitochondrial damage with the resultant effect of less endothelial cell apoptosis and EMP release. L1 could protect endothelial cells from iron-induced toxic effects and minimize EMP release, which could be potentially helpful in a subgroup of thalassemia patients who have increased thromboembolic complications.

X-linked adrenoleukodystrophy (X-ALD) is an inherited neurodegenerative disorder associated with mutations of the ABCD1 gene that encodes a peroxisomal transmembrane protein. It results in accumulation of very long chain fatty acids in tissues and body fluid. Along with other factors such as epigenetic and environmental involvement, ABCD1 mutation-provoked disorders can present different phenotypes including cerebral adrenoleukodystrophy (cALD), adrenomyeloneuropathy (AMN), and peripheral neuropathy. cALD is the most severe form that causes death in young childhood. Bone marrow transplantation and hematopoietic stem cell gene therapy are only effective when performed at an early stage of onsets in cALD. Nonetheless, current research and development of novel therapies are hampered by a lack of in-depth understanding disease pathophysiology and a lack of reliable cALD models. The Abcd1 and Abcd1/Abcd2 knock-out mouse models as well as the deficiency of Abcd1 rabbit models created in our lab, do not develop cALD phenotypes observed in human beings. In this review, we summarize the clinical and biochemical features of X-ALD, the progress of pre-clinical and clinical studies. Challenges and perspectives for future X-ALD studies are also discussed.

Progressive loss of nucleus pulposus cells (NPCs) is associated with the onset of intervertebral disc degeneration (IDD). Transplantation of NPCs, derived from human pluripotent stem cells including ESC/iPSCs, may offer a novel therapy for IDD. Nonetheless notochordal differentiation and NPC generation from human ESC/iPSC are poorly understood. We developed a three-step protocol to directly differentiate ESC/iPSC towards mesodermal, then notochordal and finally NPCs. Our results showed that notochordal-like cells (NCCs) were successfully derived from the first two-steps of the protocol. Furthermore, these cells could be differentiated into NPCs. These NPCs expressed the tyrosine kinase receptor Tie2 (Tie2), disialoganglioside 2 (GD2), Collagen II and Aggrecan. Genome-wide transcriptomic analyses by sequencing (RNA-seq) revealed the expression of a wide array of extra-cellular matrix (ECM) genes, up-stream regulators and pathways. Cross-comparison of our RNA-seq profiles with human body-derived NPC data confirmed the differentiated products were more similar to NPCs than ESC/iPSCs. Transplantation of NPCs effectively attenuated disc injury in a rat model of IDD. We utilized CRISPR/Cas9 to seamlessly knock in an enhanced fluorescent protein (GFP) to the loci of the Noto gene in ESCs for NCC generation. Our study achieved effective notochordal differentiation and transcriptomic insight into the use of human ESC/iPSCs.

Bone marrow-derived mesenchymal stem cells (BM-MSCs) contribute to myocardial repair after myocardial infarction (MI) by secreting a panel of growth factors and cytokines. This study was to investigate the potential mechanisms of the nuclear casein kinase and cyclin-dependent kinase substrate 1 (NUCKS) in regulation of the profiles of BM-MSCs secretion and compare the therapeutic efficacy of NUCKS-/-- and wide type-BM-MSCs (WT-BM-MSCs) on MI. The secretion profiles between NUCKS-/-- and WT-BM-MSCs under hypoxia (1%O2) were analyzed. Gene function analysis showed that compared with WT-BM-MSCs-conditioned medium (CdM), some genes over-presented in NUCKS-/--BM-MSCs-CdM were closely associated with inflammatory response, regulation of cell proliferation, death, migration and secretion. Notably, VEGFa in NUCKS-/--BM-MSCs-CdM was higher than that of WT-BM-MSCs-CdM. WT-BM-MSCs and NUCKS-/--BM-MSCs were transplanted into the peri-infarct region in mice of MI. At 4 weeks after cell transplantation, NUCKS-/-- or WT-BM-MSCs group significantly improved heart function and vessels density and reduced infarction size and apoptosis of cardiomyocytes. Furthermore, NUCKS-/--BM-MSCs provided better cardioprotective effects than WT-BM-MSCs against MI. Our study demonstrates that depletion of NUCKS enhances the therapeutic efficacy of BM-MSCs for MI via regulating the secretion.

Background & Aim Adrenoleukodystrophy (X-ALD) is an X-linked disease. ALD is caused by mutations of the gene encoding ATP-Binding cassette subfamily D member 1 (ABCD1), a peroxisomal transmembrane protein. Dysfunctional ABCD1 protein results in excessive accumulation of very long chain fatty acid (VLCFA) in neural system and leads to demyelination and neural death. Currently, no effective treatments are available to cure X-ALD except BMT at very early stage of disease. Gene therapy using virus as a vehicle is an efficient method to transfer a target gene to human cells. Adeno-associated virus (AAV)-based gene therapy is of high interest for current research. The mechanism of AAV gene transfer does not cause any insertions of target gene into the human genome, which highly enhance the safety of the therapy. There are different serotypes of AAV, each targets different cell types. Therefore, AAV would be a promising vector to cure different diseases in the future. Methods, Results & Conclusion Here in this project, AAV vector with functional ABCD1 gene is constructed and its effectiveness is being tested in vitro for treating X-ALD. Meanwhile, a new animal model – ABCD1 gene mutated rabbit is used to mimic condition of X-ALD patients. Compared to the same age wild type rabbits, the diseased model shows a 5-10 folds increase in plasma VLCFA level before the treatment, and magnetic resonance imaging (MRI) scan is performed to determine demyelination inside the CNS. After AAV injection, rabbits' blood VLCFA level is monitored regularly, MRI scan and brain tissue sectioning are examined to determine the effectiveness of the AAV-based gene therapy targeting X-ALD.

SummaryThe segmental premature aging disease Hutchinson-Gilford Progeria syndrome (HGPS) is caused by a truncated and farnesylated form of Lamin A called progerin. HGPS affects mesenchymal lineages, including the skeletal system, dermis, and vascular smooth muscle (VSMC). To understand the underlying molecular pathology of HGPS, we derived induced pluripotent stem cells (iPSCs) from HGPS dermal fibroblasts. The iPSCs were differentiated into neural progenitors, endothelial cells, fibroblasts, VSMCs, and mesenchymal stem cells (MSCs). Progerin levels were highest in MSCs, VSMCs, and fibroblasts, in that order, with these lineages displaying increased DNA damage, nuclear abnormalities, and HGPS-VSMC accumulating numerous calponin-staining inclusion bodies. Both HGPS-MSC and -VSMC viability was compromised by stress and hypoxia in vitro and in vivo (MSC). Because MSCs reside in low oxygen niches in vivo, we propose that, in HGPS, this causes additional depletion of the MSC pool responsible for replacing differentiated cells lost to progerin toxicity.