modeling-mitochondrial-disease-using-brain-organoids-focus-on

Modeling Mitochondrial Disease Using Brain Organoids: A Focus on Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like Episodes

Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like episodes (MELAS) are mitochondrial disorders most commonly caused by a m.3243A&#62;G ...

Keio University School of Medicine

Columbia University Medical Center

Laboratory studies have shown that angiotensin receptor blockers (ARBs) can affect extracellular matrix (ECM) metabolism and thereby have a beneficial effect on vascular remodeling. The aim of this study was to examine the clinical effects of the ARB candesartan cilexetil on serum markers of synthesis and degradation of ECM, as well as their relation to changes in arterial stiffness in hypertensive patients. Twenty-three patients with essential hypertension were recruited for this study. Markers related to ECM synthesis and degradation (procollagen type 1 propeptide [PIP], procollagen type III propeptide [PIIIP], matrix metalloproteinase-3 [MMP-3, stromelysin-1], tissue inhibitor of matrix metalloproteinases [TIMP-1], and hyaluronic acid [HA]) were examined both before and after one year of treatment with candesartan. Pulse-wave velocity [PWV] and ankle-brachial pressure index [ABI] were measured two months (i.e., after achieving blood pressure reduction) and one year after the initiation of therapy. PWV values after one year of treatment with ARB were significantly decreased compared to previous values, whereas ABI values were unchanged. Treatment with ARB was also associated with a significant decrease in serum PIIIP values and an increase in serum stromelysin-1, whereas changes in PIP, TIMP-1, and HA did not achieve statistical significance. A significant relationship was found between the changes in PWV and the changes in stromelysin-1 levels after correction for blood pressure and heart rate (p = 0.02). These results suggest that the treatment for just one year with ARB results in significant changes in markers of ECM metabolism as well as PWV. These effects on ECM metabolism could have a beneficial effect in decreasing vascular pathology in patients with essential hypertension.

Effects of the angiotensin receptor blocker candesartan on arterial stiffness and markers of extracellular matrix metabolism in patients with essential hypertension.

Altered DNA methylation plays an important role in the onset and progression of kidney disease. However, little is known about how the changes arise in disease states. Here, we report that KAT5-mediated DNA damage repair is essential for the maintenance of kidney podocytes and is associated with DNA methylation status. Podocyte-specific KAT5-knockout mice develop severe albuminuria with increased DNA double-strand breaks (DSBs), increased DNA methylation of the nephrin promoter region, and decreased nephrin expression. Podocyte KAT5 expression is decreased, whereas DNA DSBs and DNA methylation are increased in diabetic nephropathy; moreover, KAT5 restoration by gene transfer attenuates albuminuria. Furthermore, KAT5 decreases DNA DSBs and DNA methylation at the same nephrin promoter region, which indicates that KAT5-mediated DNA repair may be related to DNA methylation status. These results suggest a concept in which an environment of DNA damage repair, which occurs with decreased KAT5, may affect DNA methylation status.

Decreased KAT5 Expression Impairs DNA Repair and Induces Altered DNA Methylation in Kidney Podocytes.

The common marmoset (marmoset; Callithrix jacchus) harbors various desired features as a non-human primate (NHP) model for neuroscience research. Recently, efforts have been made to induce neural cells in vitro from marmoset pluripotent stem cells (PSCs), including embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), which are characterized by their capacity to differentiate into all cell types from the three germ layers. Successful generation of marmoset neural cells is not only invaluable for understanding neural development and for modeling neurodegenerative and psychiatric disorders, but is also necessary for the phenotypic screening of genetically-modified marmosets. However, differences in the differentiation propensity among PSC lines hamper the applicability and the reproducibility of differentiation methods. To overcome this limitation, we evaluated the efficacy of small molecules for neural differentiation of marmoset ESCs (cjESCs) and iPSCs using multiple differentiation methods. By immunochemical and transcriptomic analyses, we confirmed that our methods using the small molecules are efficient for various differentiation protocols by either enhancing the yield of a mixture of neural cells including both neurons and glial cells, or a pure population of neurons. Collectively, our findings optimized in vitro neural differentiation methods for marmoset PSCs, which would ultimately help enhance the utility of the animal model in neuroscience.

Evaluating the efficacy of small molecules for neural differentiation of common marmoset ESCs and iPSCs.

Obtaining differentiated cells with high physiological functions by an efficient, but simple and rapid differentiation method is crucial for modeling neuronal diseases in vitro using human pluripotent stem cells (hPSCs). Currently, methods involving the transient expression of one or a couple of transcription factors have been established as techniques for inducing neuronal differentiation in a rapid, single step. It has also been reported that microRNAs can function as reprogramming effectors for directly reprogramming human dermal fibroblasts to neurons. In this study, we tested the effect of adding neuronal microRNAs, miRNA-9/9*, and miR-124 (miR-9/9*-124), for the neuronal induction method of hPSCs using Tet-On-driven expression of the Neurogenin2 gene (), a proneural factor. While it has been established that  can facilitate differentiation from pluripotent stem cells into neurons with high purity due to its neurogenic effect, a long or indefinite time is required for neuronal maturation with  misexpression alone. With the present method, the cells maintained a high neuronal differentiation rate while exhibiting increased gene expression of neuronal maturation markers, spontaneous calcium oscillation, and high electrical activity with network bursts as assessed by a multipoint electrode system. Moreover, when applying this method to iPSCs from Alzheimer's disease (AD) patients with  () or  () mutations, cellular phenotypes such as increased amount of extracellular secretion of amyloid β42, abnormal oxygen consumption, and increased reactive oxygen species in the cells were observed in a shorter culture period than those previously reported. Therefore, it is strongly anticipated that the induction method combining  and miR-9/9*-124 will enable more rapid and simple screening for various types of neuronal disease phenotypes and promote drug discovery.

miRNA-Based Rapid Differentiation of Purified Neurons from hPSCs Advancestowards Quick Screening for Neuronal Disease Phenotypes In Vitro.

Extended pluripotent stem cells (EPSCs) derived from mice and humans showed an enhanced potential for chimeric formation. By exploiting transcriptomic approaches, we assessed the differences in gene expression profile between extended EPSCs derived from mice and humans, and those newly derived from the common marmoset (marmoset; Callithrix jacchus). Although the marmoset EPSC-like cells displayed a unique colony morphology distinct from murine and human EPSCs, they displayed a pluripotent state akin to embryonic stem cells (ESCs), as confirmed by gene expression and immunocytochemical analyses of pluripotency markers and three-germ-layer differentiation assay. Importantly, the marmoset EPSC-like cells showed interspecies chimeric contribution to mouse embryos, such as E6.5 blastocysts in vitro and E6.5 epiblasts in vivo in mouse development. Also, we discovered that the perturbation of gene expression of the marmoset EPSC-like cells from the original ESCs resembled that of human EPSCs. Taken together, our multiple analyses evaluated the efficacy of the method for the derivation of marmoset EPSCs.

Article	Year
Effects of the angiotensin receptor blocker candesartan on arterial stiffness and markers of extracellular matrix metabolism in patients with essential hypertension. Clinical and experimental hypertension (New York, N.Y. : 1993)\| PubMed ID: 16820347	2006
Decreased KAT5 Expression Impairs DNA Repair and Induces Altered DNA Methylation in Kidney Podocytes. Cell reports\| PubMed ID: 30699357	2019
Evaluating the efficacy of small molecules for neural differentiation of common marmoset ESCs and iPSCs. Neuroscience research\| PubMed ID: 31586586
miRNA-Based Rapid Differentiation of Purified Neurons from hPSCs Advancestowards Quick Screening for Neuronal Disease Phenotypes In Vitro. Cells\| PubMed ID: 32106535	2020
Attempts for deriving extended pluripotent stem cells from common marmoset embryonic stem cells. Genes to cells : devoted to molecular & cellular mechanisms\| PubMed ID: 36530170	2023

Mari Nakamura

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