Development
Abstract
Leucine-zipper-like post translational regulator 1 (LZTR1) is a member of the BTB-Kelch superfamily, which regulates the RAS proteostasis. Autosomal dominant (AD) mutations in LZTR1 have been identified in patients with Noonan syndrome (NS), a congenital anomaly syndrome. However, it remains unclear whether LZTR1 AD mutations regulate the proteostasis of the RAS subfamily molecules or cause NS-like phenotypes in vivo. To elucidate the pathogenesis of LZTR1 mutations, we generated two novel LZTR1 mutation knock-in mice (Lztr1G245R/+ and Lztr1R409C/+), which correspond to the human p.G248R and p.R412C mutations, respectively. LZTR1-mutant male mice exhibit low birth weight, distinctive facial features, and cardiac hypertrophy. Cardiomyocyte size and the expression of RAS subfamily members, including MRAS and RIT1, were significantly increased in the left ventricles (LVs) of mutant male mice. LZTR1 AD mutants did not interact with RIT1 and functioned as dominant-negative forms of wild-type LZTR1. Multi-omics analysis revealed that the MAPK signaling pathway was activated in the LVs of mutant mice. Treatment with the MEK inhibitor trametinib ameliorated cardiac hypertrophy in mutant male mice. These results suggest that MEK/ERK pathway is a therapeutic target for NS-like phenotype resulting from dysfunction of RAS proteostasis by LZTR1 AD mutations.
Authors
Taiki Abe, Kaho Morisaki, Tetsuya Niihori, Miho Terao, Shuji Takada, Yoko Aoki
Abstract
Our objective was to interrogate infant mesenchymal stem cell (MSC) lipid metabolism and gestational exposures that may contribute to child obesity risk. MSCs were cultured from term infants of mothers with obesity (n=16) or normal-weight (n=15). In MSCs undergoing myogenesis in vitro, we used lipidomics to distinguish phenotypes by unbiased cluster analysis and lipid challenge (24h excess fatty acid, 24hFA). We measured MSC AMP-activated protein kinase (AMPK) activity and fatty acid oxidation (FAO), and a composite index of maternal glucose, insulin, triglycerides, free fatty acids, tumor necrosis factor-α, high density lipoprotein- and total- cholesterol in fasting blood from mid- and late-gestation (~17, ~27wks). We measured child adiposity at birth (n=29), 4-6m (n=29), and 4-6y (n=13). Three MSC clusters were distinguished by triacylglycerol (TAG) stores, with greatest TAGs in Cluster-2. All Clusters increased acylcarnitines and TAGs with 24hFA, though Cluster-2 was more pronounced and corresponded to AMPK activation and FAO. Maternal metabolic markers predicted MSC Clusters and child adiposity at 4-6y (both highest in Cluster-3). Our data supports that MSC phenotypes are predicted by comprehensive maternal metabolic milieu exposures, independent of maternal BMI, and suggest utility as an at-birth predictor for child adiposity, though validation with larger longitudinal samples is warranted.
Authors
Lauren E. Gyllenhammer, Vincent Zaegel, Allison M. Duensing, Manoel Lixandrao, Dana Dabelea, Bryan C. Bergman, Kristen E. Boyle
Abstract
Craniofacial dysmorphisms are among the most common birth defects. Proteasome mutations frequently result in craniofacial dysmorphisms, including lower jaw malformations; however, the underlying mechanisms are unknown. Here, we used a zebrafish proteasome subunit β 1 (psmb1) mutant to define the cellular mechanisms underlying proteasome mutation-induced craniofacial dysmorphisms. psmb1 mutants exhibited a flattened ceratohyal and smaller Meckel’s and palatoquadrate cartilages. Ceratohyal flattening was a result of failed chondrocyte convergent extension, accompanied by reduced numbers of chondrocytes in the lower jaw due to defects in chondrocyte differentiation. Morphogenesis of craniofacial muscles and tendons was similarly perturbed. psmb1 mutants lacked the hyohyal muscles, and craniofacial tendons were shortened and disorganized. We additionally identified a critical period for proteasome function in craniofacial development, specifically during chondrocyte and muscle differentiation. psmb1 overexpression in sox10+ cells of mutant embryos rescued both cartilage and tendon phenotypes but induced only a partial rescue of the muscle phenotype, indicating that psmb1 was required in both tissue-autonomous and nonautonomous fashions during craniofacial development. Overall, our work demonstrates that psmb1 is required for craniofacial cartilage, tendon, and muscle differentiation and morphogenesis.
Authors
Bess M. Miller, Wolfram Goessling
Abstract
Childhood obesity and its adverse health consequences have risen worldwide, with low socioeconomic status increasing the risk in high-income countries like the US. Understanding the interplay between childhood obesity, cognition, socioeconomic factors, and the brain is crucial for prevention and treatment. Using data from the ABCD study, we investigated how body mass index (BMI) relates to brain structural and functional connectivity metrics. Obese/overweight children (n = 2,356) were more likely to live in poverty and exhibited lower cognitive performance compared to normal weight children (n = 4,754). Higher BMI was associated with multiple brain measures that were strongest for lower longitudinal diffusivity in corpus callosum, increased activity in cerebellum, insula, and somatomotor cortex, and decreased functional connectivity in multimodal brain areas, with effects more pronounced among children from low-income families. Notably, nearly 80% of the association of low income and 70% of the association of impaired cognition on BMI were mediated by higher brain activity in somatomotor areas. Increased resting activity in somatomotor areas and decreased structural and functional connectivity likely contribute to the higher risk of overweight/obesity among children from low-income families. Supporting low-income families and implementing educational interventions to improve cognition may promote healthy brain function and reduce the risk of obesity.
Authors
Dardo Tomasi, Nora D. Volkow
Abstract
Suppressor of Fused (SUFU) is widely regarded as a key negative regulator of the Sonic Hedgehog (SHH) morphogenic pathway and a known tumor suppressor of medulloblastoma (MB). However, we report here that SUFU expression was markedly increased in 75% of specimens compiled in a tissue array comprising 49 unstratified MBs. The SUFU and GLI1 expression levels in this MB array showed strong positive correlation, which was also identified in a large public dataset containing 736 MBs. We further report that increasing Sufu gene dosage in mice caused pre-axial polydactyly, which was associated with the expansion of the Gli3 domain in the anterior limb bud and heightened Shh signaling responses during embryonic development. Increasing Sufu gene dosage also led to accelerated cerebellar development and, when combined with ablation of the Shh receptor encoded by Patched1 (Ptch1), promoted medulloblastoma tumorigenesis. These data reveal multi-faceted roles of SUFU in promoting MB tumorigenesis by enhancing SHH signaling. This revelation clarifies potentially counter-intuitive clinical observation of high SUFU expression in MBs and may pave way for novel strategies to reduce or reverse MB progression.
Authors
Boang Han, Yu Wang, Shen Yue, Yun-hao Zhang, Lun Kuang, Bin-bin Gao, Yue Wang, Ziyu Zhang, Xiaohong Pu, Xin-fa Wang, Chi-chung Hui, Ting-ting Yu, Chen Liu, Steven Y. Cheng
Abstract
Rare diseases are underrepresented in biomedical research, leading to insufficient awareness. Zhu-Tokita-Takenouchi-Kim (ZTTK) syndrome is a rare disease caused by genetic alterations that result in heterozygous loss-of-function of SON. While ZTTK syndrome patients suffer from numerous symptoms, the lack of model organisms hampers our understanding of SON and this complex syndrome. Here, we developed Son haploinsufficiency (Son+/−) mice as a model of ZTTK syndrome and identified the indispensable roles of Son in organ development and hematopoiesis. Son+/− mice recapitulated clinical symptoms of ZTTK syndrome, including growth retardation, cognitive impairment, skeletal abnormalities, and kidney agenesis. Furthermore, we identified hematopoietic abnormalities in Son+/− mice, including leukopenia and immunoglobulin deficiency, similar to those observed in human patients. Surface marker analyses and single-cell transcriptome profiling of hematopoietic stem and progenitor cells revealed that Son haploinsufficiency shifts cell fate more toward the myeloid lineage but compromises lymphoid lineage development by reducing genes required for lymphoid and B-cell lineage specification. Additionally, Son haploinsufficiency causes inappropriate activation of erythroid genes and impaired erythropoiesis. These findings highlight the importance of the full gene expression of Son in multiple organs. Our model serves as an invaluable research tool for this rare disease and related disorders associated with SON dysfunction.
Authors
Lana Vukadin, Bohye Park, Mostafa Mohamed, Huashi Li, Amr Elkholy, Alex Torrelli-Diljohn, Jung-Hyun Kim, Kyuho Jeong, James M. Murphy, Caitlin A. Harvey, Sophia Dunlap, Leah Gehrs, Hanna Lee, Hyung-Gyoon Kim, Jay Prakash Sah, Seth N. Lee, Denise Stanford, Robert A. Barrington, Jeremy B. Foote, Anna G. Sorace, Robert S. Welner, Blake E. Hildreth III, Ssang-Taek Steve Lim, Eun-Young Erin Ahn
Abstract
The development of human prenatal adaptive immunity progresses faster than previously appreciated, with the emergence of memory CD4+ T cells alongside regulatory T (Treg) cells by mid-gestation. We previously identified a prenatal-specific population of PLZF+ CD4+ T cells with heightened effector potential that were enriched in the developing intestine and accumulated in the cord blood of infants exposed to prenatal inflammation. However, the signals that drive their tissue distribution and effector maturation are unknown. Here we define the transcriptional and functional heterogeneity of human prenatal PLZF+ CD4+ T cells and identify the compartmentalization of T helper (Th)-like effector function across the small intestine (SI) and mesenteric lymph nodes (MLN). IL-7 was more abundant in the SI relative to the MLN and drove the preferential expansion of naïve PLZF+ CD4+ T cells via enhanced STAT5 and MEK/ERK signaling. Exposure to IL-7 was sufficient to induce the acquisition of CD45RO expression and rapid effector function in a subset of PLZF+ CD4+ T cells, identifying a human analog of memory-phenotype CD4+ T cells. Further, IL-7 modulated the differentiation of Th1- and Th17-like PLZF+ CD4+ T cells, and thus likely contributes to the anatomic compartmentalization of human prenatal CD4+ T cell effector function.
Authors
Veronica Locher, Sara Park, Daniel G. Bunis, Stephanie Makredes, Margareta Mayer, Trevor D. Burt, Gabriela K. Fragiadakis, Joanna Halkias
Abstract
Osteogenesis imperfecta (OI), brittle bone disease, is a disorder characterized by bone fragility and increased fracture incidence. All forms of OI also feature short stature, implying an effect on endochondral ossification. Using the Aga2+/- mouse, which has a mutation in type I collagen, we show an affected growth plate primarily due to a shortened proliferative zone. We used scRNAseq analysis of tibial and femoral growth plate tissues to understand transcriptional consequences on growth plate cell types. We show that perichondrial cells, which express abundant type I procollagen, and growth plate chondrocytes, which were found to express low amounts of type I procollagen, had ER stress and dysregulation of the same UPR pathway as previously demonstrated in osteoblasts. Aga2+/- proliferating chondrocytes showed increased FGF and MAPK signaling, findings consistent with accelerated differentiation. There was also increased Sox9 expression throughout the growth plate, which is expected to accelerate early chondrocyte differentiation but reduce late hypertrophic differentiation. These data reveal that mutant type I collagen expression in OI has a previously unappreciated impact on the cartilage growth plate. These effects on endochondral ossification indicate that OI is a biologically complex phenotype going beyond its known impacts on bone to negatively affect linear growth.
Authors
Jennifer Zieba, Lisette Nevarez, Davis Wachtell, Jorge H. Martin, Alexander Kot, Sereen Wong, Daniel H. Cohn, Deborah Krakow
Abstract
Glioblastoma (GBM) is the most lethal brain cancer with a dismal prognosis. Stem-like GBM cells (GSCs) are a major driver of GBM propagation and recurrence, thus understanding the molecular mechanisms that promote GSCs may lead to effective therapeutic approaches. Through in vitro clonogenic growth-based assays, we determined mitogenic activities of the ligand molecules that are implicated in neural development. We have identified that Semaphorin 3A (Sema3A), originally known as an axon guidance molecule in the central nervous system, promotes clonogenic growth of GBM cells but not normal neural progenitor cells (NPCs). Mechanistically, Sema3A binds to its receptor Neuropilin-1 (NRP1) and facilitates an interaction between NRP1 and TGF receptor 1 (TGFR1), which in turn leads to activation of canonical TGF signaling in both GSCs and NPCs. TGF signaling enhances self-renewal and survival of GBM tumors through induction of key stem cell factors, but it evokes cytostatic responses in NPCs. Blockage of the Sema3A-NRP1 axis via shRNA-mediated knockdown of Sema3A or NRP1 impeded clonogenic growth and TGF pathway activity in GSCs and inhibited tumor growth in vivo. Taken together, these findings suggest that the Sema3A-NRP1-TGFR1 signaling axis is a critical regulator of GSC propagation and a potential therapeutic target for GBM.
Authors
Hye-Min Jeon, Yong Jae Shin, Jaehyun Lee, Nakho Chang, Dong-Hun Woo, Won Jun Lee, Dayna Nguyen, Wonyoung Kang, Hee Jin Cho, Heekyoung Yang, Jin-Ku Lee, Jason K. Sa, Yeri Lee, Donggeon Kim, Benjamin W. Purow, Yeup Yoon, Do-Hyun Nam, Jeongwu Lee
Abstract
The adrenal glands synthesize and release essential steroid hormones such as cortisol and aldosterone, but many aspects of human adrenal gland development are not well understood. Here, we combined single-cell and bulk RNA sequencing, spatial transcriptomics, IHC, and micro-focus computed tomography to investigate key aspects of adrenal development in the first 20 weeks of gestation. We demonstrate rapid adrenal growth and vascularization, with more cell division in the outer definitive zone (DZ). Steroidogenic pathways favored androgen synthesis in the central fetal zone, but DZ capacity to synthesize cortisol and aldosterone developed with time. Core transcriptional regulators were identified, with localized expression of HOPX (also known as Hop homeobox/homeobox-only protein) in the DZ. Potential ligand-receptor interactions between mesenchyme and adrenal cortex were seen (e.g., RSPO3/LGR4). Growth-promoting imprinted genes were enriched in the developing cortex (e.g., IGF2, PEG3). These findings reveal aspects of human adrenal development and have clinical implications for understanding primary adrenal insufficiency and related postnatal adrenal disorders, such as adrenal tumor development, steroid disorders, and neonatal stress.
Authors
Ignacio del Valle, Matthew D. Young, Gerda Kildisiute, Olumide K. Ogunbiyi, Federica Buonocore, Ian C. Simcock, Eleonora Khabirova, Berta Crespo, Nadjeda Moreno, Tony Brooks, Paola Niola, Katherine Swarbrick, Jenifer P. Suntharalingham, Sinead M. McGlacken-Byrne, Owen J. Arthurs, Sam Behjati, John C. Achermann
No posts were found with this tag.
