Biology subjects

Kolanus, W.

Publications and source records attributed to Kolanus, W..

8 recordsLinked to original sources

bioRxiv2026

The RNA-binding protein TRIM71 Promotes Supporting Cell Reprogramming and Hair Cell Regeneration by Activating Sall4

Hair cell (HC) loss in the auditory organ (cochlea) is irreversible and represents the leading cause of deafness in humans. The absence of HC regeneration is primarily due to the limited plasticity of cochlear supporting cells (SCs). Using a novel doxycycline-inducible TRIM71 transgenic mouse model, this study demonstrates that overexpression of the RNA-binding protein TRIM71 promotes spontaneous cochlear HC regeneration in neonatal mice. Experiments in cochlear organoids indicate that TRIM71 reprograms SCs into progenitor-like cells and that this reprogramming is further enhanced by coactivation of follistatin (FST). FST augments TRIM71-induced increases in chromatin accessibility at progenitor and HC-specific gene loci, facilitating their transcriptional activation in SCs. Notably, FST also enhances TRIM71-induced reactivation of Sall4, which, like Trim71, is highly expressed in early otic progenitors. Using cochlear organoids and explants, we show that the early otic transcription factor SALL4 is required for TRIM71-induced HC formation. By contrast, SALL4 overexpression inhibits HC formation by maintaining reprogrammed SCs in an undifferentiated, proliferative state. These findings establish TRIM71 as an activator of HC regeneration in vivo, provide mechanistic insights into TRIM71's role in SC reprogramming, and identify SALL4 as its essential effector.

cell biology↗

bioRxiv2025

Title: The RNA-binding protein TRIM71 is essential for hearing in humans and mice and regulates the timing of auditory sensory organ development

The RNA-binding protein TRIM71 is essential for brain development, and recent genetic studies in humans have identified TRIM71 as a risk gene for congenital hydrocephaly (CH). Here, we show that mono-allelic missense mutations in TRIM71 are associated with hearing loss (HL) and inner ear aplasia in humans. Utilizing conditional Trim71 knockout mice carrying a CH and HL-associated mutation, we demonstrate that loss of TRIM71 function during early otic development (embryonic day 9-10) causes severe hearing loss. While inner ear morphogenesis occurs normally in Trim71 knockout mice, we find that early otic loss of TRIM71 function disrupts the highly stereotyped timing of cell cycle exit and differentiation within the inner ear auditory sensory organ (cochlea), resulting in the premature formation and innervation of mechano-sensory hair cells. Transcriptomic profiling of Trim71 deficient cochlear progenitor cells identifies Inhba and Tgfbr2 as targets of TRIM71 repression, and our analysis of InhbaTgfbr1 double knockout mice indicates that TRIM71 maintains hair cell progenitors in a proliferative and undifferentiated state by restricting TGF-{beta}-type signaling. Characterization of hair cells and their associated neurons in adult Trim71 knockout mice revealed abnormally short inner hair cell stereocilia, reduced pre-synaptic terminals, and neuronal degeneration in the outer hair cell region, providing a basis for the observed hearing deficits in Trim71 knockout mice.

neuroscience↗

bioRxiv2024

Dysregulation of gene expression during gastrulation results in impaired primitive erythropoiesis and vascular development in Trim71-KO embryos

The transition of an embryo from gastrulation to organogenesis requires precisely coordinated changes in gene expression. The RNA-binding protein Trim71 is essential for embryonic survival, but its exact role in mammalian development in vivo remains poorly defined. Here we show that murine Trim71-KO embryos appear normal until embryonic day (E)8.5 but display severe defects in primitive erythropoiesis, yolk sac vasculature and heart function during the onset of organogenesis at E9.5 and E10.5. This led to an impaired vascular translocation of yolk sac-derived macrophage progenitors to the embryo head, independent of Trim71 expression in erythro-myeloid progenitors. The cardiovascular and erythropoiesis defects explain the embryonic lethality upon global Trim71-KO. Targeting Trim71 in hematoendothelial progenitors did not induce strong developmental defects, indicating an earlier developmental origin of these phenotypes in Trim71-KO embryos. ScRNA-seq of E7.5 Trim71-KO embryos revealed that transcriptomic changes arise already at gastrulation, showing a strong upregulation of the transcription factor Eomes. We identify Eomes as a direct target of Trim71-mediated mRNA repression via the NHL domain, demonstrating a functional link of Trim71 to a key regulator of mesodermal development. Taken together, our data suggest that Trim71-dependent control of gene expression at gastrulation establishes a framework for proper development during organogenesis.

developmental biology↗

bioRxiv2023

Reactivation of the progenitor gene Trim71 enhances the mitotic and hair cell-forming potential of cochlear supporting cells

Cochlear hair cell loss is a leading cause of deafness in humans. Neighboring supporting cells have some capacity to regenerate hair cells. However, their regenerative potential sharply declines as supporting cells undergo maturation (postnatal day 5 in mice). We recently reported that reactivation of the RNA-binding protein LIN28B restores the hair cell-regenerative potential of P5 cochlear supporting cells. Here, we identify the LIN28B target Trim71 as a novel and equally potent enhancer of supporting cell plasticity. TRIM71 is a critical regulator of stem cell behavior and cell reprogramming, however, its role in cell regeneration is poorly understood. Employing an organoid-based assay, we show that TRIM71 reactivation increases the mitotic and hair cell-forming potential of P5 cochlear supporting cells by facilitating their de-differentiation into progenitor-like cells. Our mechanistic work indicates that TRIM71s RNA-binding activity is essential for such ability, and our transcriptomic analysis identifies gene modules that are linked to TRIM71 and LIN28B-mediated supporting cell reprogramming. Furthermore, our study uncovers that the TRIM71-LIN28B target Hmga2 is essential for supporting cell self-renewal and hair cell formation.

neuroscience↗

bioRxiv2022

GPR183 targets lung-resident CD301b+ conventional dendritic cells type 2 to a subtissular TSLP-TSLP receptor-mediated survival niche within the adventitial cuff

Conventional dendritic cells (cDCs) are strategically localized throughout non-lymphoid tissues. How such spatially regulated subtissular placement is achieved remains largely elusive. Here, we reveal that GPR183 targets CD301b+ cDC2 to a TSLP-dependent survival niche within the adventital cuff. We identified a close association of CD301b+ cDC2 with PDGFR+ fibroblasts within the adventitial region of the lung. Genetic ablation of GPR183 within the cDC lineage leads to a selective loss of CD301b+ cDC2 in conjunction with the loss of CD301b+ cDC2 : fibroblast colocalization. Next bone marrow chimeric experiments and expression studies suggested adventitial fibroblasts as the main source of 7,25 hydroxycholesterol, the natural ligand of GPR183. Single cell transcriptomic receptor ligand inference and subsequent genetic validation revealed TSLP receptor signalling as a crucial fibroblast derived CD301b+ cDC2 survival factor. These data expose a subtissular localization mechanism for tissue-specific functionalization of CD301b+ cDC2.

immunology↗

bioRxiv2021

TRIM71 deficiency causes germ cell loss during mouse embryogenesis and promotes human male infertility

Mutations affecting the germline can result in infertility or the generation of germ cell tumors (GCT), highlighting the need to identify and characterize the genes controlling the complex molecular network orchestrating germ cell development. TRIM71 is a stem cell-specific factor essential for embryogenesis, and its expression has been reported in GCT and adult mouse testes. To investigate the role of TRIM71 in mammalian germ cell embryonic development, we generated a germline-specific conditional Trim71 knockout mouse (cKO) using the early primordial germ cell (PGC) marker Nanos3 as a Cre-recombinase driver. cKO mice are infertile, with male mice displaying a Sertoli cell-only (SCO) phenotype, which in humans is defined as a specific subtype of non-obstructive azoospermia characterized by the absence of developing germ cells in the testes seminiferous tubules. Infertility originates during embryogenesis, as the SCO phenotype was already apparent in neonatal mice. The in vitro differentiation of mouse embryonic stem cells (ESCs) into PGC-like cells (PGCLCs) revealed reduced numbers of PGCLCs in Trim71-deficient cells. Furthermore, in vitro growth competition assays with wild type and CRISPR/Cas9-generated TRIM71 mutant NCCIT cells, a human GCT-derived cell line which we used as a surrogate model for proliferating PGCs, showed that TRIM71 promotes NCCIT cell proliferation and survival. Our data collectively suggest that germ cell loss in cKO mice results from combined defects during the specification and maintenance of PGCs prior to their sex determination in the genital ridges. Last, via exome sequencing analysis, we identified several TRIM71 variants in a cohort of infertile men, including a loss-of-function variant in a patient with SCO phenotype. Our work reveals for the first time an association of TRIM71 variants with human male infertility, and uncovers further developmental roles for TRIM71 in the generation and maintenance of germ cells during mouse embryogenesis.

developmental biology↗

bioRxiv2021

The stem cell-specific protein TRIM71 inhibits maturation and activity of the pro-differentiation miRNA let-7 via two independent molecular mechanisms

The stem cell-specific RNA-binding protein TRIM71/LIN-41 was the first identified target of the pro-differentiation and tumor suppressor miRNA let-7. TRIM71 has essential functions in embryonic development and a proposed oncogenic role in several cancer types, such as hepatocellular carcinoma. Here, we show that TRIM71 regulates let-7 expression and activity via two independent mechanisms. On the one hand, TRIM71 enhances pre-let-7 degradation through its direct interaction with LIN28 and TUT4, thereby inhibiting let-7 maturation and indirectly promoting the stabilization of let-7 targets. On the other hand, TRIM71 represses the activity of mature let-7 via its RNA-dependent interaction with the RNA-Induced Silencing Complex (RISC) effector protein AGO2. We found that TRIM71 directly binds and stabilizes let-7 targets, suggesting that let-7 activity inhibition occurs on active RISCs. MiRNA enrichment analysis of several transcriptomic datasets from mouse embryonic stem cells and human hepatocellular carcinoma cells suggests that these let-7 regulatory mechanisms shape transcriptomic changes during developmental and oncogenic processes. Altogether, our work reveals a novel role for TRIM71 as a miRNA repressor and sheds light on the precise mechanistic dual regulation of let-7.

molecular biology↗

bioRxiv2017

Cellular reprogramming of human monocytes is regulated by time-dependent IL4 signalling and NCOR2

The clinical and therapeutic value of human in vitro generated monocyte-derived dendritic cell (moDC) and macrophages is well established. However, in line with recent findings regarding myeloid cell ontogeny and due to our limited understanding of their physiological counterparts, transcriptional regulation and heterogeneity, the full potential of these important cellular systems is still underestimated.\n\nIn this study, we use cutting edge high-dimensional analysis methods to better understand the transcriptional organization, phenotypic heterogeneity and functional differences between human ex vivo isolated and in vitro generated mononuclear phagocytes with the aim to better realize their full potential in the clinic.\n\nWe demonstrate that human monocytes activated by MCSF or GMCSF most closely resemble inflammatory macrophages identified in vivo, while IL4 signalling in the presence of GMCSF generates moDCs resembling inflammatory DCs in vivo, but not steady state cDC1 or cDC2. Moreover, these reprogramming regimes lead to activated monocytes that present with profoundly different transcriptomic, metabolic, phenotypic and functional profiles. Furthermore, we demonstrate that CD14+ monocytes are integrating multiple exogenous activation signals such as GMCSF and IL4 in a combinatorial and temporal fashion, resulting in a high-dimensional cellular continuum of reprogrammed monocytes dependent on the mode and timing of cytokine exposure. Utilizing nanostraw-based knockdown technology, we demonstrate that the IL4-dependent generation of moDCs relies on the induction, nuclear localization and function of the transcriptional regulator NCOR2.\n\nFinally, we unravel unappreciated heterogeneity within the clinically moDCs population and propose a novel high-dimensional phenotyping strategy to better tailor clinical quality control strategies for patient need and culture conditions to enhance therapeutic outcome.

immunology↗