Biology subjects

Wartiovaara, K.

Publications and source records attributed to Wartiovaara, K..

4 recordsLinked to original sources

bioRxiv2026

Human models of GLE1 associated LCCS1 reveal neural crest deficiency and multisystem developmental failure accompanied by altered RNA metabolism

Lethal congenital contracture syndrome 1 (LCCS1) is a neurodevelopmental disorder caused by GLE1 c.432-10A>G variant and presenting fetal akinesia, defects in anterior horn spinal cord, skin, skull, and skeletal muscle development. The uniform prenatal lethality of LCCS1 limits access to patient material, thereby hindering mechanistic studies in physiologically relevant models. To overcome this, human embryonic stem cells (hESCs) carrying the LCCS1 variant, patient-derived fetal fibroblasts, and transcriptomic and proteomic profiling were utilized to examine early GLE1 dysfunction in human cells and tissues. Across LCCS1 cell types, reduced global transcription and translation were observed, while nucleocytoplasmic poly(A)+ RNA distribution was unchanged. Despite its context-dependent effects on proliferation, LCCS1 variant altered mRNA decay kinetics and increased stress granule formation in differentiated cells. LCCS1 hESCs retained core pluripotency but reduced choline acetyltransferase and {beta} tubulin III levels, together with increased neurofilament inclusion incidence, indicate functional immaturity in differentiated spinal motor neurons. Differentiation of LCCS1 hESC-derived gastruloids uncovered broad perturbations in neuromuscular and neural crest derivative development, results which were supported by phenotypes detected in ectodermal organoids and fetal LCCS1 tissue. These findings provide new mechanistic insight into LCCS1 pathogenesis and establish a robust human model framework for studying neurodevelopmental disorders.

developmental biology↗

bioRxiv2024

Finnish gyrate atrophy mutation OAT;c.1205C>T leads to accumulation of intracellular GABA

Hyperornithinaemia with gyrate atrophy of choroid and retina (HOGA) is a recessive metabolic disease caused by dysfunction of the ornithine aminotransferase (OAT) gene, leading to ornithine accumulation and a complex metabolic imbalance. This causes retinal degeneration that ultimately evolve to blindness. However, the mechanisms of this degeneration remain unknown. Here, we have conducted untargeted metabolomic analysis in patient-derived induced pluripotent stem cells and their isogenic counterparts. Mutant cells show altered levels of ornithine-related metabolites, including low creatine, proline and glutamate, and elevated arginine and citrulline. The untargeted metabolomics approach revealed changes in the urea cycle and polyamine synthesis pathways with a significant intracellular accumulation of gamma-aminobutyric acid (GABA). Hence, we propose GABA as a key player in the disease pathogenicity, potentially affecting neuronal function in the eye.

biochemistry↗

bioRxiv2023

CRISPR/Cas9 DNA synthesis disruption as a tool to control cell proliferation in vitro and in vivo

Engineered cells hold great promise for regenerative medicine and gene therapy. However, living cell products entail a fundamental biological risk of unwanted growth. Here, we describe a novel metabolic safety system to control cell proliferation without added genetic elements. We inactivated a key enzyme for nucleotide metabolism, TYMS, in several cell lines, thus obtaining cells that proliferate only when supplemented with exogenous thymidine but fail to replicate in its absence. Under supplementation, TYMS-/- pluripotent stem cells proliferate normally, produce teratomas and differentiate into potentially therapeutic cell types such as pancreatic beta cells. After differentiation, the postmitotic cells do not require thymidine to function, as seen by prolonged in vivo production of human insulin in implanted mice. Hence, this method allows robust cell culture and manufacture while mitigating the risk of uncontrolled growth of transplanted cells. One Sentence Summary: Genetic disruption of DNA synthesis prevents unwanted proliferation in cell therapies without affecting cell function.

bioengineering↗

bioRxiv2018

CRISPR-Cas9 interrogation of a putative fetal globin repressor in human erythroid cells.

Sickle Cell Disease and {beta}-thalassemia, which are caused by defective or deficient adult {beta}-globin (HBB) respectively, are the most common serious genetic blood diseases in the world. Expression of the fetal {beta}-like globin, also known as {gamma}-globin, can ameliorate both disorders by serving in place of the adult {beta}-globin. Here we use CRISPR-Cas9 gene editing to explore a putative {gamma}-globin silencer region identified by comparison of naturally-occurring deletion mutations associated with up-regulated {gamma}-globin. We find that deletion of a 1.7 kb consensus element or select 350 bp sub-regions from bulk populations of cells increases levels of fetal hemoglobin (HbF) or {gamma}-globin. Screening of individual sgRNAs in one sub-region revealed three single guides that caused mild increases in {gamma}-globin expression. However, clonal cell lines with the 1.7 kb region deleted did not up-regulate {gamma}-globin and neither did lines with either of two of sub-regions identified in the screen deleted. These data suggest that the region is not an autonomous {gamma}-globin silencer, and thus by itself is not a suitable therapeutic target in the {beta}-hemoglobinopathies.

genetics↗