Tuberculosis is a global public health problem with emergence of multidrug-resistant infections. Previous epidemiological studies of tuberculosis in Thailand have identified a clonal outbreak multidrug-resistant strain of Mycobacterium tuberculosis in the Kanchanaburi province, designated “MKR superspreader”, and this particular strain later was found to also spread to other regions. In this study, we elucidated its biology through RNA-Seq analyses and identified a set of genes involved in cholesterol degradation to be up-regulated in the MKR during the macrophage cell infection, but not in the H37Rv reference strain. We also found that the bacterium up-regulated genes associated with the ESX-1 secretion system during its intracellular growth phase, while the H37Rv did not. All results were confirmed by qRT-PCR. Moreover, we showed that compounds previously shown to inhibit the mycobacterial ESX-1 secretion system and cholesterol utilisation, and FDA-approved drugs known to interfere with the host cholesterol transportation were able to decrease the intracellular survival of the MKR when compared to the untreated control, while not that of the H37Rv. Altogether, our findings suggested that such pathways are important for the MKR’s intracellular growth, and potentially could be targets for the discovery of new drugs against this emerging multidrug-resistant strain of M. tuberculosis.

A patient with b E /b 0 -thalassemia major was converted to transfusion-independence 4.5 years ago by lentiviral gene transfer in hematopoietic stem cells while showing a myeloid-biased cell clone. Induced pluripotent stem cells (iPSCs) are a potential alternative source of hematopoietic stem cells. If fetal to adult globin class, switching does not occur in vivo in iPSC-derived erythroid cells, b-globin gene transfer would be unnecessary. To investigate both vector integration skewing and the potential use of iPSCs for the treatment of thalassemia, we derived iPSCs from the thalassemia gene therapy patient and compared iPSCderived hematopoietic cells to their natural isogenic somatic counterparts. In NSG immunodeficient mice, embryonic to fetal and a partial fetal to adult globin class switching were observed, indicating that the gene transfer is likely necessary for iPSC-based therapy of the bhemoglobinopathies. Lentivector integration occurred in regions of low and high genotoxicity. Surprisingly, common integration sites (CIS) were identified across those iPSCs and cells retrieved from isogenic and nonisogenic gene therapy patients with b-thalassemia and adrenoleukodystrophy, respectively. This suggests that CIS observed in the absence of overt tumorigenesis result from nonrandom lentiviral integration rather than oncogenic in vivo selection. These findings bring the use of iPSCs closer to practicality and further clarify our interpretation of genome-wide lentivector integration.

Mycobacterium tuberculosis utilizes several mechanisms to block phagosome-lysosome fusion to evade host cell restriction. However, induction of host cell autophagy by starvation was shown to overcome this block, resulting in enhanced lysosomal delivery to mycobacterial phagosomes and the killing of the M. tuberculosis reference strain H37Rv. Nevertheless, our previous studies found that strains belonging to the M. tuberculosis Beijing genotype can resist starvation-induced autophagic elimination, though the mycobacterial factors involved remain unclear. In this study, we showed that KatG expression is upregulated in the autophagy-resistant M. tuberculosis Beijing strain (BJN) during autophagy induction by the starvation of host macrophages, while such increase was not observed in the H37Rv. KatG depletion using the CRISPR-dCas9 interference system in the BJN resulted in increased lysosomal delivery to its phagosome and decreased its survival upon autophagy induction by starvation. As KatG functions by catabolizing ROS, we determined the source of ROS contributing to the starvation-induced autophagic elimination of mycobacteria. Using siRNA-mediated knockdown, we found that Superoxide dismutase 2, which generates mitochondrial ROS but not NADPH oxidase 2, is important for the starvation-induced lysosomal delivery to mycobacterial phagosomes. Taken together, these findings showed that KatG is vital for the BJN to evade starvation-induced autophagic restriction.

Background The use of a personalized liver organoid derived from human-induced pluripotent stem cells (HuiPSCs) is advancing the use of in vitro disease models for the design of specific, effective therapies for individuals. Collecting patient peripheral blood cells for HuiPSC generation is preferable because it is less invasive; however, the capability of blood cell-derived HuiPSCs for hepatic differentiation and liver organoid formation remains uncertain. Moreover, the currently available methods for liver organoid formation require a multistep process of cell differentiation or a combination of hepatic endodermal, endothelial and mesenchymal cells, which is a major hurdle for the application of personalized liver organoids in high-throughput testing of drug toxicity and safety. To demonstrate the capability of blood cell-derived HuiPSCs for liver organoid formation without support from endothelial and mesenchymal cells. Methods The peripheral blood-derived HuiPSCs first differentiated into hepatic endoderm (HE) in two-dimensional (2D) culture on Matrigel-coated plates under hypoxia for 10 days. The HE was then collected and cultured in 3D culture using 50% Matrigel under ambient oxygen. The maturation of hepatocytes was further induced by adding hepatocyte growth medium containing HGF and oncostatin M on top of the 3D culture and incubating the culture for an additional 12–17 days. The function of the liver organoids was assessed using expression analysis of hepatocyte-specific gene and proteins. Albumin (ALB) synthesis, glycogen and lipid storage, and metabolism of indocyanine were evaluated. The spatial distribution of albumin was examined using immunofluorescence and confocal microscopy. Results CD34+ hematopoietic cell-derived HuiPSCs were capable of differentiating into definitive endoderm expressing SOX17 and FOXA2, hepatic endoderm expressing FOXA2, hepatoblasts expressing AFP and hepatocytes expressing ALB. On day 25 of the 2D culture, cells expressed SOX17, FOXA2, AFP and ALB, indicating the presence of cellular heterogeneity. In contrast, the hepatic endoderm spontaneously formed a spherical, hollow structure in a 3D culture of 50% Matrigel, whereas hepatoblasts and hepatocytes could not form. Microscopic observation showed a single layer of polygonal-shaped cells arranged in a 3D structure. The hepatic endoderm-derived organoid synthesis ALB at a higher level than the 2D culture but did not express definitive endoderm-specific SOX17, indicating the greater maturity of the hepatocytes in the liver organoids. Confocal microscopic images and quantitative ELISA confirmed albumin synthesis in the cytoplasm of the liver organoid and its secretion. Overall, 3D culture of the hepatic endoderm is a relatively fast, simple, and less laborious way to generate liver organoids from HuiPSCs that is more physiologically relevant than 2D culture.

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Induced pluripotent stem cells (iPSCs) were generated from skin fibroblasts isolated from a 58-year old male with a L150P mutation in the presenilin 1 (PSEN-1) gene, which is responsible for the majority of familial cases of Alzheimer's disease (AD). The iPSCs were established by co-electroporation with episomal plasmids containing hOCT4, hSOX2, hL-MYC, hKLF4, hNANOG, hLIN28, and short hairpin RNA against TP53. The iPSCs contained the specific heterozygous mutation c.449C>T, had normal karyotype, expressed the expected pluripotency genes and displayed in vitro differentiation potential to the three germ layers. The iPSCs may be useful for studying familial AD pathology in vitro.

Summary Thalassaemia is characterized by the reduced or absent production of globins in the haemoglobin molecule leading to imbalanced α‐globin/non α‐globin chains. HbE, the result of a G to A mutation in codon 26 of the HBB (β‐globin) gene, activates a cryptic 5′ splice site in codon 25 leading to a reduction of correctly spliced βE‐globin (HBB:c.79G>A) mRNA and consequently β+‐thalassaemia. A wide range of clinical severities in bothα‐ and β‐thalassaemia syndromes, from nearly asymptomatic to transfusion‐dependent, has been observed. The correlation between clinical heterogeneity in various genotypes of thalassaemia and the levels of globin gene expression and βE‐globin pre‐mRNA splicing were examined using multiplex quantitative real‐time reverse transcription polymerase chain reaction (RT‐qPCR) and allele‐specific RT‐qPCR. The α‐globin/non α‐globin mRNA ratio was demonstrated to be a good indicator for disease severity among different thalassaemia disorders. However, the α‐globin/non α‐globin mRNA ratio ranged widely in β‐thalassaemia/HbE patients, with no significant difference between mild and severe phenotypes. Interestingly, the correctly to aberrantly spliced βE‐globin mRNA ratio in 30% of mild β‐thalassaemia/HbE patients was higher than that of the severe patients. The splicing process of βE‐globin pre‐mRNA differs among β‐thalassaemia/HbE patients and serves as one of the modifying factors for disease severity.

Spinocerebellar ataxia type 2 (SCA2) is a neurodegenerative disease primarily affecting the cerebellum. Very little is known about the molecular mechanisms underlying the disease and, to date, no cure or treatment is available. We have successfully generated bona fide induced pluripotent stem cell (iPSC) lines of SCA2 patients in order to study a disease-specific phenotype. Here, we demonstrate the gene correction of the iPSC line H271 clone 1 where we have exchanged the expanded CAG repeat of the ATXN2 gene with the normal length found in healthy alleles. This gene corrected cell line will provide the ideal control to model SCA2 by iPSC technology.