Richard Finnell

Sonic hedgehog (Shh) signaling regulates embryonic morphogenesis utilizing primary cilia, the cell antenna acting as a signaling hub. Fuz, an effector of planar cell polarity (PCP) signaling, involves Shh signaling via cilia formation, while the G protein-coupled receptor 161 (Gpr161) is a negative regulator of Shh signaling. The range of phenotypic malformations observed in mice bearing mutations in either of these two genes is similar; however, their functional relations have not been previously explored. This study identified the genetic and biochemical link between Fuz and Gpr161 in mouse embryonic development. Fuz was genetically epistatic to Gpr161 via Shh signaling during mouse embryonic development. The FUZ biochemically interacted with GPR161, and Fuz regulated Gpr161 ciliary trafficking via β-arrestin2. Our study suggested the novel Gpr161-Fuz axis that regulates Shh signaling during mouse …

Neural tube closure (NTC) is a highly synchronized morphological process driven by mechanical forces, and any disruptions during this process can lead to neural tube defects (NTDs). However, mechanical properties associated with NTDs are largely unknown. To understand the correlation between NTDs and biomechanical properties, we imaged NTC using multimodal Brillouin microscopy and optical coherence tomography in two mutant mice lines, where the genes Mthfd1l and Fuz were inactivated. We also imaged cerebral organoids cultured in dolutegravir for 10 and 14 days. Our results showed a clear link between NTDs and neural tube biomechanical properties.

MethodsOver 500 allele agnostic ASOs were computationally designed to induce degradation of HNRNPH2 mRNA. A total of 56 were screened in vitro. Human neurons were treated with each ASO at low (400nM), medium (2μM) and high (10μM) concentrations. TaqMan RT-qPCR assay was used to determine HNRNPH2 and HHNNPH1 gene expression changes, with human large ribosomal protein (PRLPO) as endogenous control.ResultsSeven ASO candidates were tested. Four (ASOs 16, 33, 731, and 1239) produced significant concentration-dependent reductions in HNRNPH2, by more than 90%, and three (ASOs 33, 39, and 1239) caused significant concentration-dependent increases in the expression of HNRNPH1 (up to a 750% increase). Nullizygous hnrnph2 mice and humanized HNRNPH2 knock-in mice were generated at the Jackson Laboratory and the phenotypic expression of these alleles are …

We provide insights on the mechanisms activated by MSCs in utero and discuss the advantages of MSC-free approaches, as minimally invasive tools capable of functional tissue repair while reducing the limitations of current therapeutics.

The mechanisms involved in neural tube formation are complex and can be easily disrupted. Neurulation is one such process, governed by mechanical forces where tissues physically fold and fuse. When neural tube folding and closure fail to complete during neurulation, it results in structural and functional abnormalities of the brain and spinal cord. Thus, it is important to understand the interplay between forces and tissue stiffness during neurulation. Brillouin microscopy is an all-optical, noninvasive, high-resolution imaging technique capable of mapping tissue stiffness, but it cannot provide structural information, resulting in “blind” imaging. To overcome this limitation, we have combined a Brillouin microscopy system with optical coherence tomography (OCT) in one synchronized and co-aligned instrument to provide structural guidance when mapping the biomechanical properties of neural tube formation in …

The etiology of neural tube defects (NTDs) involves complex gene-environmental interactions. Folate is the largest modifier of NTD risk, but mechanisms remain unclear. Here, we identify the DNA demethylase TET1 as a nexus of folate metabolism and genetic risk factors post-gastrulation. We observed cranial NTDs in Tet1 null embryos at contrasting penetrance in inbred versus genetically heterogenous strains. Furthermore, we identified a risk locus harboring a hotspot of genes co-regulated by a strain-dependent interaction between TET1 and developmental signaling pathways during neural induction. Adverse maternal dietary folic acid (FA) status interacts with the loss of TET1 to affect offspring DNA methylation primarily at neurogenesis loci. Conversely, excess FA in Tet1 null embryos drives promoter DNA hypermethylation and reduced expression of membrane solute transporters, associated with reduced FA intake and disruption of phospholipid metabolism. Overall, our study unravels interactions between modified maternal FA status, Tet1 gene dosage and genetic backgrounds that impact neurotransmitter functions, response to cell-extrinsic inputs, and individual susceptibility to congenital disorders.

Neural tube defects (NTDs) are the most common congenital anomalies of the CNS. It is widely appreciated that both genetic and environmental factors contribute to their etiology. The inability to ascribe clear genetic patterns of inheritance to various NTD phenotypes suggests it is possible that epigenetic mechanisms are involved in the etiology of NTDs. In this context, the contribution of DNA methylation as an underlying contributing factor to the etiology of NTDs has been extensively reviewed. Here, an updated accounting of the evidence linking post-translational histone modifications to these birth defects, relying heavily upon studies in humans, and the possible molecular implications inferred from reports based on cellular and animal models, are presented.

The environment created during embryogenesis contributes to reducing aberrations that drive structural malformations and tumorigenesis. In this study, we investigate the anti-cancer effect of mesenchymal stem cells (MSCs) derived from 2 different gestational tissues, the amniotic fluid (AF) and the chorionic villi (CV), with emphasis on their secretome. Transcriptomic analysis was performed on patient-derived AF- and CV-MSCs collected during prenatal diagnosis and identified both mRNAs and lncRNAs, involved in tissue homeostasis and inhibiting biological processes associated with the etiology of aggressive cancers while regulating immune pathways shown to be important in chronic disorders. Secretome enrichment analysis also identified soluble moieties involved in target cell regulation, tissue homeostasis, and cancer cell inhibition through the highlighted Wnt, TNF, and TGF-β signaling pathways …

ImportanceThe association of fetal exposure to antiseizure medications (ASMs) with outcomes in childhood are not well delineated.ObjectiveTo examine the association of fetal ASM exposure with subsequent adaptive, behavioral or emotional, and neurodevelopmental disorder outcomes at 2, 3, and 4.5 years of age.Design, Setting, and ParticipantsThe Maternal Outcomes and Neurodevelopmental Effects of Antiepileptic Drugs (MONEAD) study is a prospective, observational cohort study conducted at 20 epilepsy centers in the US. A total of 456 pregnant women with epilepsy or without epilepsy were enrolled from December 19, 2012, to January 13, 2016. Children of enrolled women were followed up with formal assessments at 2, 3, 4.5, and 6 years of age. Statistical analysis took place from August 2022 to May 2023.ExposuresExposures included mother’s epilepsy status as well as mother’s ASM blood …

Progress and clinical prospect of genomic structural variants investigation Progress and clinical prospect of genomic structural variants investigation Sci Bull (Beijing). 2024 Jan 28:S2095-9273(24)00062-8. doi: 10.1016/j.scib.2024.01.035. Online ahead of print. Authors Zhongzhong Chen 1 , Richard H Finnell 2 , Yunping Lei 3 , Hongyan Wang 4 Affiliations 1 Obstetrics and Gynecology Hospital, State Key Laboratory of Genetic Engineering, Institute of Reproduction and Development, Fudan University, Shanghai 200011, China; Shanghai Children's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200062, China. 2 Center for Precision Environmental Health, Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston 77030, USA; Departments of Molecular and Human Genetics and Medicine, Baylor College of Medicine, One Baylor Plaza, Houston 77030, USA. 3 Center …

T-box transcription factor T (TBXT; T) is required for mesodermal formation and axial skeletal development. Although it has been extensively studied in various model organisms, human congenital vertebral malformations (CVMs) involving T are not well established. Here, we report a family with 15 CVM patients distributed across four generations. All affected individuals carry a heterozygous mutation, T c.596A > G (p.Q199R), which is not found in unaffected family members, indicating co-segregation of the genotype and phenotype. In vitro assays show that T p.Q199R increases the nucleocytoplasmic ratio and enhances its DNA-binding affinity, but reduces its transcriptional activity compared to the wild-type. To determine the pathogenicity of this mutation in vivo, we generated a Q199R knock-in mouse model that recapitulates the human CVM phenotype. The heterozygous Q199R mice show subtle kinked or …

Fetal hydrops as detected by prenatal ultrasound usually carries a poor prognosis depending on the underlying aetiology. We describe the prenatal and postnatal clinical course of two unrelated female probands in whom de novo heterozygous missense variants in the planar cell polarity gene CELSR1 were detected using exome sequencing. Using several in vitro assays, we show that the CELSR1 p.(Cys1318Tyr) variant disrupted the subcellular localisation, affected cell-cell junction, impaired planar cell polarity signalling and lowered proliferation rate. These observations suggest that deleterious rare CELSR1 variants could be a possible cause of fetal hydrops.

Heparan sulfate proteoglycan 2 (HSPG2) gene encodes the matrix protein Perlecan, and genetic inactivation of this gene creates mice that are embryonic lethal with severe neural tube defects (NTDs). We discovered rare genetic variants of HSPG2 in 10% cases compared to only 4% in controls among a cohort of 369 NTDs. Endorepellin, a peptide cleaved from the domain V of Perlecan, is known to promote angiogenesis and autophagy in endothelial cells. The roles of enderepellin in neurodevelopment remain unclear so far. Our study revealed that endorepellin can migrate to the neuroepithelial cells and then be recognized and bind with the neuroepithelia receptor neurexin in vivo. Through the endocytic pathway, the interaction of endorepellin and neurexin physiologically triggers autophagy and appropriately modulates the differentiation of neural stem cells into neurons as a blocker, which is necessary for …

Folate deficiency contribute to neural tube defects (NTDs) which could be rescued by folate supplementation. However, the underlying mechanisms are still not fully understood. Besides, there is considerable controversy concerning the forms of folate used for supplementation. To address this controversy, we prepared culture medium with different forms of folate, folic acid (FA), and 5‐methyltetrahydrofolate (5mTHF), at concentrations of 5 μM, 500 nM, 50 nM, and folate free, respectively. Mouse embryonic fibroblasts (MEFs) were treated with different folates continuously for three passages, and cell proliferation and F‐actin were monitored. We determined that compared to 5mTHF, FA showed stronger effects on promoting cell proliferation and F‐actin formation. We also found that FOLR1 protein level was positively regulated by folate concentration and the non‐canonical Wnt/planar cell polarity (PCP) pathway …

Objectives:In 2018, the Botswana Tsepamo Study reported a nine-fold increased risk of neural tube defects in infants whose mothers were treated with dolutegravir (DTG) from the time of conception. As maternal folate supplementation and status is a well known modifier of neural tube defect (NTD) risk, we sought to evaluate birth outcomes in mice fed normal and low folic acid diets treated with DTG during pregnancy.Design:DTG was evaluated for developmental toxicity using pregnant mice fed normal or low folic acid diet.Methods:CD-1 mice were provided diet with normal (3 mg/kg) or low (0.3 mg/kg) folic acid. They were treated with water, a human therapeutic-equivalent dose, or supratherapeutic dose of DTG from mouse embryonic day E6. 5 to E12. 5. Pregnant dams were sacrificed at term (E18. 5) and fetuses were inspected for gross, internal, and skeletal defects.Results:Fetuses with exencephaly, an NTD …

BackgroundDown syndrome (DS) clinical multisystem condition is generally considered the result of a genetic imbalance generated by the extra copy of chromosome 21. Recent discoveries, however, demonstrate that the molecular mechanisms activated in DS compared to euploid individuals are more complex than previously thought. Here, we utilize mesenchymal stem cells from chorionic villi (CV) to uncover the role of comprehensive functional genomics-based understanding of DS complexity.MethodsNext-generation sequencing coupled with bioinformatic analysis was performed on CV obtained from women carrying fetuses with DS (DS-CV) to reveal specific genome-wide transcriptional changes compared to their euploid counterparts. Functional assays were carried out to confirm the biological processes identified as enriched in DS-CV compared to CV (i.e., cell cycle, proliferation features …

Neural tube closure is a complex process driven by mechanical forces, but this process can be disturbed leading to development defects. So, to understand the interplay between forces and tissue stiffness during neurulation, we developed a multimodal Brillouin microscopy and optical coherence system (OCT). OCT provides structural guidance while mapping the biomechanical properties of embryonic neural tube using Brillouin microscopy. 3D-OCT, 2D-OCT, and 2D-Brillouin images of Mthfd1l and Fuz knockout mouse embryos at gestation days 9.5 and 10.5 were acquired. Our results show overall decrease in the stiffness of homozygotic knockout neural tube tissues compared to the wildtype.

Orofacial clefts, including cleft lip and palate (CL/P) and neural tube defects (NTDs) are among the most common congenital anomalies, but knowledge of the genetic basis of these conditions remains incomplete. The extent to which genetic risk factors are shared between CL/P, NTDs and related anomalies is also unclear. While identification of causative genes has largely focused on coding and loss of function mutations, it is hypothesized that regulatory mutations account for a portion of the unidentified heritability. We found that excess expression of Grainyhead-like 2 (Grhl2) causes not only spinal NTDs in Axial defects (Axd) mice but also multiple additional defects affecting the cranial region. These include orofacial clefts comprising midline cleft lip and palate and abnormalities of the craniofacial bones and frontal and/or basal encephalocele, in which brain tissue herniates through the cranium or into the …

Dear Editor, It is well established that folic acid (FA) supplementation can significantly reduce the risk of birth defects, including neural tube defects (NTDs) 1 and congenital heart defects (CHDs) 2. More than 80 nations have adopted mandatory FA food fortification programs 3. With additional FA intake from different dietary supplements, a portion of the population is exposed to FA concentrations over the 0.4 mg recommended daily allowance (RDA) 4. These people include women who had a prior NTD complicated pregnancy and are planning to start a new pregnancy 5, and men with fertility issues who are treated with high-dose FA (12.5 times of RDA) supplementation to improve sperm counts 6. However, there is a lack of research on whether excessive FA intake has the potential to harm human beings. Recently, a case with “pseudo-MTHFR” syndrome was reported, a wild-type MTHFR Caucasian woman with a …

Changes in maternal nutrient availability due to diet or disease significantly increase the risk of neural tube defects (NTDs). Because the incidence of metabolic disease continues to rise, it is urgent that we better understand how altered maternal nutrient levels can influence embryonic neural tube development. Furthermore, primary neurulation occurs before placental function during a period of histiotrophic nutrient exchange. In this review we detail how maternal metabolites are transported by the yolk sac to the developing embryo. We discuss recent advances in understanding how altered maternal levels of essential nutrients disrupt development of the neuroepithelium, and identify points of intersection between metabolic pathways that are crucial for NTD prevention.Neural tube closure requires essential nutrients from the maternal environment Neural tube formation is a crucial early step of brain and spinal cord …