Biology subjects

Spoutil, F.

Publications and source records attributed to Spoutil, F..

4 recordsLinked to original sources

bioRxiv2025

Post-transcriptional control of enamel matrix mineralization by TENT5A-mediated cytoplasmic polyadenylation

Tooth enamel formation, or amelogenesis, is a complex biomineralization process regulated by ameloblasts cells. These cells secrete enamel matrix proteins (EMPs), including Amelogenin (AMELX) and Ameloblastin (AMBN), which are essential for hydroxyapatite crystal deposition during enamel mineralization. Precise regulation of this process ensures the mechanical and chemical strength of dental enamel. Using Tent5a knock-out (KO) mouse, we demonstrated that TENT5A, a non-canonical poly(A) polymerase is crucial for the stability, translation, and secretion of EMP mRNAs, particularly AMELX, during amelogenesis. TENT5A-deficient mice exhibited Amelogenesis imperfecta, characterized by enamel hypomineralization, reduced thickness, and disrupted ultrastructure, as revealed by micro-computed tomography. Through nanopore direct mRNA sequencing, we identified that TENT5A polyadenylates Amelx and other mRNAs encoding secreted proteins, enhancing their stability and translation in the endoplasmic reticulum. Moreover, loss of TENT5A altered AMELX secretion and extracellular self-assembly, impairing matrix organization and hydroxyapatite deposition. This study highlights the role of TENT5A in post-transcriptional regulation during enamel formation, demonstrating its importance in enamel homeostasis. TeaserTENT5A adds poly(A) tails to specific mRNAs in enamel, enhancing their expression, which is crucial for dental mineralization.

developmental biology↗

bioRxiv2025

FAM83H regulates postnatal T cell development through thymic stroma organization

Family of Sequence Similarity 83H (FAM83H/ SACK1H) is primarily expressed in epithelial cells, where it interacts with casein kinase 1 (CK1) and keratins to regulate cytoskeletal organization, cell proliferation, and vesicular trafficking. Mutations in FAM83H are known to cause amelogenesis imperfecta, highlighting its critical role in enamel formation. We generated Fam83h-deficient mice (Fam83hem2(IMPC)Ccpcz, Fam83h-/-) and mice lacking a part of the N-terminal CK1-binding domain (Fam83h{Delta}87/{Delta}87). Consistent with other Fam83h-deficient models, these mice are subviable, smaller in size, and exhibit a sparse, scruffy coat, scaly skin, general weakness, and hypoactivity. Notably, both strains show impaired lymphoid cell development in early postnatal life. In the thymus, Fam83h expression is confined to thymic epithelial cells (TECs), and its deficiency in stromal cells results in disrupted thymic architecture and severe block in the expansion of DN3 (double-negative stage 3) T cells, ultimately leading to insufficient T cell production. Single-cell transcriptomic analysis reveals that Fam83h-/- cortical TECs (cTECs) express reduced levels of the TEC master regulator Foxn1, and its multiple downstream target genes, suggesting a critical role for FAM83H likely in coordination with CK1in cTEC maturation. HighlightsFam83h-deficient mice exhibit multiple epithelial defects, but no obvious enamel defects Fam83h deficiency disrupts lymphocyte development Fam83h deficiency impairs thymic epithelial cell maturation and thymus function

immunology↗

bioRxiv2020

Cytoplasmic polyadenylation by TENT5A is required for proper bone formation

Osteoblasts orchestrate bone formation by secreting dense, highly cross-linked type I collagen and other proteins involved in osteogenesis. Mutations in Col11, Col12, or collagen biogenesis factors lead to the human genetic disease, osteogenesis imperfecta (OI). Herein, we show that the TENT5A gene, whose mutation is responsible for poorly characterized type XVIII OI, encodes an active cytoplasmic poly(A) polymerase regulating osteogenesis. TENT5A is induced during osteoblast differentiation and TENT5A KO osteoblasts are defective in mineralization. The TENT5A KO mouse recapitulates OI disease symptoms such as bone fragility and hypomineralization. Direct RNA sequencing revealed that TENT5A polyadenylates and increases expression of Col11 and Col12 RNAs, as well as those of other genes mutated in OI, resulting in lower production and improper folding of collagen chains. Thus, we have identified the specific pathomechanism of XVIII OI and report for the first time a biologically relevant post-transcriptional regulator of collagen production. We further postulate that TENT5A, possibly together with its paralogue TENT5C, is responsible for the wave of cytoplasmic polyadenylation of mRNAs encoding secreted proteins occurring during bone mineralization.

genetics↗

bioRxiv2019

Regulation of neutrophil NADPH oxidase by PSTPIP2 affects bone damage in murine autoinflammatory osteomyelitis

Autoinflammatory diseases are characterized by dysregulation of the innate immune system leading to spontaneous inflammation. Pstpip2cmo mouse strain is a well-characterized model of this class of disorders. Due to the mutation leading to the lack of adaptor protein PSTPIP2, these animals suffer from autoinflammatory chronic multifocal osteomyelitis similar to several human syndromes. Current evidence suggests that it is driven by hyperproduction of IL-1{beta} by neutrophil granulocytes. Here we show that in addition to IL-1{beta}, PSTPIP2 also negatively regulates ROS generation by neutrophil NADPH oxidase. Pstpip2cmo neutrophils display highly elevated ROS production in response to a range of stimuli. Inactivation of NADPH oxidase in Pstpip2cmo mice did not affect IL-1{beta} levels and the autoinflammatory process was initiated with similar kinetics. However, the bone destruction was almost completely alleviated, suggesting that dysregulated NADPH oxidase activity is a key factor promoting autoinflammatory bone damage in Pstpip2cmo mice.

immunology↗