Biology subjects

Tang, R.

Publications and source records attributed to Tang, R..

At least 55 records · Page 3Linked to original sources

bioRxiv2023

Designer Fat Cells: Adipogenic Differentiation of CRISPR-Cas9 Genome-Engineered Induced Pluripotent Stem Cells

Adipose tissue is an active endocrine organ that can signal bidirectionally to many tissues and organ systems in the body. With obesity, adipose tissue is a source of low-level inflammation that contributes to various co-morbidities and damage to downstream effector tissues. The ability to synthesize genetically engineered adipose tissue could have critical applications in studying adipokine signaling and the use of adipose tissue for novel therapeutic strategies. This study aimed to develop a method for non-viral adipogenic differentiation of genome-edited murine induced pluripotent stem cells (iPSCs) and to test the ability of such cells to engraft in mice in vivo. Designer adipocytes were created from iPSCs, which can be readily genetically engineered using CRISPR-Cas9 to knock out or insert individual genes of interest. As a model system for adipocyte-based drug delivery, an existing iPSC cell line that transcribes interleukin 1 receptor antagonist under the endogenous macrophage chemoattractant protein-1 promoter was tested for adipogenic capabilities under these same differentiation conditions. To understand the role of various adipocyte subtypes and their impact on health and disease, an efficient method was devised for inducing browning and whitening of IPSC-derived adipocytes in culture. Finally, to study the downstream effects of designer adipocytes in vivo, we transplanted the designer adipocytes into fat-free lipodystrophic mice as a model system for studying adipose signaling in different models of disease or repair. This novel translational tissue engineering and regenerative medicine platform provides an innovative approach to studying the role of adipose interorgan communication in various conditions.

bioengineering↗

bioRxiv2023

Olfactory learning in Drosophila requires O-GlcNAcylation of mushroom body ribosomal subunits

O-GlcNAcylation is a dynamic post-translational modification that diversifies the proteome. Its dysregulation is associated with neurological disorders that impair cognitive function, and yet identification of phenotype-relevant candidate substrates in a brain-region specific manner remains unfeasible. By combining an O-GlcNAc binding activity derived from Clostridium perfringens OGA (CpOGA) with TurboID proximity labeling in Drosophila, we developed an O-GlcNAcylation profiling tool that translates O-GlcNAc modification into biotin conjugation for tissue-specific candidate substrates enrichment. We mapped the O-GlcNAc interactome in major brain regions of Drosophila and found that components of the translational machinery, including many ribosomal subunits, were abundantly O-GlcNAcylated in the mushroom body, the computational center of the Drosophila brain. Hypo-O-GlcNAcylation induced by ectopic expression of active CpOGA in the mushroom body decreased local ribosomal activity, leading to olfactory learning deficits that could be rescued by increasing ribosome biogenesis. Our study reveals that O-GlcNAcylation contributes to the links between protein synthesis and cognitive function in the brain learning center, and provides a useful tool for future dissection of tissue-specific functions of O-GlcNAcylation in Drosophila.

cell biology↗

bioRxiv2023

Ancient farmer and steppe pastoralist-related founding lineages contributed to the complex landscape of episodes in the diversification of Chinese paternal lineages

Ancient DNA advances have reported the complex genetic history of Eurasians, but how the knowledge of ancient subsistence strategy shifts and population movements influenced the fine-scale paternal genetic structure in East Asia has not been assessed. Here, we reported one integrated Y-chromosome genomic database of 15,530 people, including 1753 ancient people and newly-reported 919 individuals genotyped using our recently-developed targeted sequencing YHSeqY3000 panel, to explore Chinese genomic diversity, population evolutionary tracts and their genetic formation mechanism. We identified four major ancient technological innovations and population movements that shaped the landscape of Chinese paternal lineages. First, the expansion of millet farmers and early East Asians from the Yellow River Basin carrying the major O2/D subclades promoted the formation of the Sino-Tibetan peoples major composition and accelerated the Tibetan Plateaus permanent occupation. Second, rice farmers dispersal from the Yangtze River Valley carrying O1 and some sublineages of O2 contributed significantly to Tai-Kadai, Austronesian, Hmong-Mien, Austroasiatic people and southern Han Chinese. Third, Siberian-related paternal lineages of Q and C originated and boomed from Neolithic hunter-gatherers from the Mongolian Plateau and the Amur River Basin and significantly influenced the gene pools of northern Chinese. Fourth, western Eurasian-derived J, G and R lineages initially spread with Yamnaya steppe pastoralists and other proto-Indo-European people and further widely dispersed via the trans-Eurasian cultural communication along the Eurasian Steppe and the ancient Silk Road, remaining genetic trajectories in northwestern Chinese. Our work provided comprehensive modern and ancient genetic evidence to illuminate the impact of population interaction from the ancient farmer or herder-based societies on the genetic diversity patterns of modern people, revised our understandings of ancestral sources of Chinese paternal lineages, underscored the scientific imperative of the large-scale genomic resources of dense spatiotemporal underrepresented sampling populations to understand human evolutionary history.

genetics↗

bioRxiv2023

Serpine1 negatively regulates Th1 cell responses in experimental autoimmune encephalomyelitis.

Th1 cells are critical in experimental autoimmune encephalomyelitis (EAE). Serpine1 has been posited as an inhibitor of IFN{gamma} from T cells though its role in autoimmunity remains unclear. Here, we show that Serpine1 knockout (KO) mice develop EAE of enhanced severity relative to wild-type (WT) controls. Serpine1 overexpression represses Th1 cell cytokine production and pathogenicity, while Serpine1-KO:2D2 Th1 cells transfer EAE of increased severity in comparison to WT 2D2 Th1 cells. Notably, polarized Serpine1-KO Th1 cells display delayed expression of the Th1-specific inhibitory receptor, Tim-3. Serpine1-KO:Tim-3-Tg Th1 cells, which transgenically over-express Tim-3, showed increased expression of IFN{gamma} and reduced expression of the checkpoint molecules Lag-3 and PD-1 relative to WT Tim-3-Tg counterparts. Further, Serpine1 deficiency restored the EAE phenotype of Tim-3-Tg mice that normally develop mild disease. Together, we identify Serpine1 as a negative regulator of Th1 cells. Key pointsO_LISerpine1 inhibits EAE in a T cell-dependent manner. C_LIO_LISerpine1 is upregulated in Th1 cells and inhibits their pathogenicity. C_LIO_LISerpine1 promotes expression and function of Th1-specific inhibitory receptor Tim-3. C_LI

immunology↗

bioRxiv2023

Malaria resistance-related biological adaptation and complex evolutionary footprints of Tai-Kadai people inferred from 796 genomes

Pathogen-host adaptative interaction and complex population demographical processes, including admixture, drift and Darwen selection, have considerably shaped the Neolithic-to-Modern Western Eurasian population structure and genetic susceptibility to modern human diseases. However, the genetic footprints of evolutionary events in East Asia keep unknown as the underrepresentation of genomic diversity and the design of large-scale population studies. We reported one aggregated database of genome-wide-SNP variations from 796 Tai-Kadai (TK) genomes, including Bouyei first reported here, to explore the genetic history, population structure and biological adaptative features of TK-speaking people from Southern China and Southeast Asia. We found geography-related population substructure among TK-speaking people using the state-of-the-art population genetic structure reconstruction techniques based on the allele frequency spectrum and haplotype-resolved phased fragments. We found that the Northern TK-speaking people from Guizhou harboured one TK-dominant ancestry maximised in Bouyei people, and the Southern one from Thailand obtained more influences from Southeast Asians and indigenous people. We reconstructed the fitted admixture models and demographic graphs, which showed that TK-speaking people received gene flow from ancient rice farmer-related lineages related to the Hmong-Mien and Austroasiatic people and Northern millet farmers associated with the Sino-Tibetan people. Biological adaptation focused on our identified unique TK lineages related to Bouyei showed many adaptive signatures conferring Malaria resistance and low-rate lipid metabolism. Further gene enrichment, the allele frequency distribution of derived alleles, and their correlation with the incidence of Malaria further confirmed that CR1 played an essential role in the resistance of Malaria in the ancient "Baiyue" tribes.

genetics↗

bioRxiv2023

Wnt signaling couples G2 phase control with differentiation during hematopoiesis

During homeostasis, a critical balance is maintained between myeloid-like progenitors and their differentiated progeny, which function to mitigate stress and innate immune challenges. The molecular mechanisms that help achieve this balance are not fully understood. Using genetic dissection in Drosophila, we show that a Wnt6/EGFR-signaling network simultaneously controls progenitor growth, proliferation, and differentiation. Unlike G1-quiescence of stem cells, hematopoietic progenitors are blocked in the G2 phase by a {beta}-catenin-independent Wnt6 pathway that restricts Cdc25 nuclear entry and promotes cell growth. Canonical {beta}-catenin-dependent Wnt6 signaling is spatially confined to mature progenitors through localized activation of the tyrosine-kinases EGFR and Abl, which promote nuclear entry of {beta}-catenin and facilitate exit from G2. This strategy combines transcription-dependent and - independent forms of both Wnt6 and EGFR pathways to create a direct link between cell-cycle control and differentiation. This unique combinatorial strategy employing conserved components may underlie homeostatic balance and stress response in mammalian hematopoiesis.

developmental biology↗

bioRxiv2023

TRPML1 activation ameliorates lysosomal phenotypes in CLN3 deficient retinal pigment epithelial cells

Mutations in the lysosomal membrane protein CLN3 cause Juvenile Neuronal Ceroid Lipofuscinosis (JNCL). Activation of the lysosomal ion channel TRPML1 has previously been shown to be beneficial in several neurodegenerative disease models. Here, we tested whether TRPML1 activation rescues disease-associated phenotypes in CLN3-deficient retinal pigment epithelial (ARPE-19 CLN3-KO) cells. ARPE-19 CLN3-KO cells accumulate LAMP1 positive organelles and show lysosomal storage of mitochondrial ATPase subunit C (SubC), globotriaosylceramide (Gb3), and glycerophosphodiesters (GPDs), whereas lysosomal bis(monoacylglycero)phosphate (BMP/LBPA) lipid levels were significantly decreased. Activation of TRPML1 reduced lysosomal storage of Gb3 and SubC but failed to restore BMP levels in CLN3-KO cells. TRPML1-mediated decrease of storage was TFEB-independent, and we identified TRPML1-mediated enhanced lysosomal exocytosis as a likely mechanism for clearing storage including GPDs. Therefore, ARPE-19 CLN3-KO cells represent a human cell model for CLN3 disease showing many of the described core lysosomal deficits, some of which can be improved using TRPML1 agonists.

cell biology↗

bioRxiv2023

Distinguished biological adaptation architecture aggravated population differentiation of Tibeto-Burman-speaking people inferred from 500 whole genome data from 39 populations

Tibeto-Burman (TB) people have tried to adapt to the hypoxic, cold and high-UV high-altitude Tibetan Plateau and complex disease exposure in the lowland wet and hot rainforest since the late Paleolithic period. However, the full landscape of genetic history and biological adaptation of geographically diverse TB people and their interaction mechanism remained unknown. We generated a whole-genome-based meta-database of 500 individuals from 39 TB populations from East Asia and Southeast Asia and presented a comprehensive landscape of genetic diversity, admixture history and differentiated adaptative features of geographically different TB people. We identified geography/language-related genetic differentiation among Tibetan Plateau, Tibetan-Yi-Corridor (TYC) and Southeast Asian TB people, consistent with their differentiated admixture process with incoming or indigenous ancestral source populations. A robust genetic connection between TYC people and ancient YR people supported the Northern origin hypothesis of TB people. We reported population substructure-related differentiated biological adaptative signatures between highland Tibetans and lowland TB people and between geographically different Lolo speakers. Highland adaptative EPAS1 and EGLN variants riched in Tibetans but lacked in TYC people whose adaptation is associated with the physical features and skin pigmentation (EDAR and SLC24A5), hepatic alcohol metabolism (ALDH9A1), regulation of cell-cell adhesion of muscle cells (CTNNA3) and immune/fat metabolism-related adaptative signature. TB-related genomic resources provided new insights into the genetic basis of phenotype differences and better reference for the anthropologically-informed sampling design in biomedical and genomic cohort research.

genetics↗

bioRxiv2023

Hypoxia-induced circSTT3A maintains Breast Cancer Stem Cell formation by Stabilizing PGK1 protein

BackgroundHypoxia is a key feature of tumor microenvironment that can cause fundamental changes in cancer cells, and may also lead to the development of breast cancer stem cells (BCSCs) with self-renewal ability. However, the mechanism of hypoxia in inducing BCSCs is not fully understood. MethodsPerforming RNA sequence and bioinformatics analysis, a hypoxia specific circular RNA (circRNA), named circSTT3A, was identified in hypoxic breast cancer cells and tissues. The clinical significance of circSTT3A was investigated in breast cancer (BC) tissues and tissue array. The loss and acquisition of circSTT3A were carried out in vivo and in vitro to confirm its functional roles in BCSC stemness maintenance. HIF1 droved circSTT3A expression was evaluated by chromatin immunoprecipitation and dual luciferase reporter assays. RNA pull-down, RNA immunoprecipitation, silver staining detection, mass spectrographic analysis, co-immunoprecipitation assays and western blotting were exerted to determine circSTT3A directly binding with HSP70 and PGK1 proteins. CircSTT3A-mediated serine metabolism was determined by UHPLC-QTRAP-MS system and ELISA kit. BC mouse model was used to assess the effects of circSTT3A/Hsp70/PGK1 on tumorigenesis and chemotherapy resistance in vivo. ResultsA novel hypoxia specific circSTT3A was significantly upregulated in clinical breast cancer tissues, and was related to the clinical stage and poor prognosis of BC patients. The hypoxia inducible factor 1 alpha (HIF1)-regulated circSTT3A has remarkable effect on mammosphere formation in breast cancer cells. Our work revealed that circSTT3A directly interacting with nucleotide-binding domain of heat shock protein 70 (HSP70) increases the ability of HSP70 to recruit phosphoglycerate kinase 1 (PGK1) via its substrate-binding domain, which reduces the ubiquitination of PGK1 and increases the stability of PGK1. The enhanced PGK1 catalyzes 1,3-diphosphoglycerate (1, 3-BPG) into 3-phosphoglycerate (3-PG) leading to 3-PG accumulation and increase of serine synthesis, thus to facilitate BCSC enrichment under hypoxic microenvironment. Loss of circSTT3A or PGK1 substantially induces suppression in tumor initiation and tumor growth, which dramatically increases tumor sensitivity to Doxorubicin treatment in mice. ConclusionsHypoxia induced circSTT3A/HSP70/PGK1 axis plays a critical role in maintaining BCSC properties and may be meaningful for treating patients with breast cancer.

cancer biology↗

bioRxiv2023

Whole-genome sequencing of ethnolinguistic diverse northwestern Chinese Hexi Corridor people from the 10K_CPGDP project suggested the differentiated East-West genetic admixture along the Silk Road and their biological adaptations

The ancient Silk Road served as the main connection between East and West Eurasia for several centuries. At any rate, the genetic exchange between populations along the ancient Silk Road was likely to leave traces on the contemporary gene pool of local people in Northwest China, which was the passage of the Northern Silk Road. However, genetic sources from northwestern China are under-represented in the current population-scale genomic database. To characterize the genetic architecture and adaptative history of the Northern Silk Road ethnic populations, we performed whole-genome sequencing on 126 individuals from six ethnolinguistic groups (Tibeto-Burman (TB)-speaking Tibetan, Mongolic (MG)-speaking Dongxiang/Tu/eastern Yugur, and Turkic (TK)-speaking Salar/western Yugur) living in Gansu and Qinghai in the 10K Chinese people Genomic Diversity Project (10K_CPGDP). We observed ethnicity-related differentiated population structures among these geographically close Northwest Chinese populations, that is, Salar and Tu people showed a close affinity with southwestern TB groups, and other studied populations shared more alleles with MG and Tungusic groups. Overall, the patterns of genetic clustering were not consistent with linguistic classifications. We estimated that Dongxiang, Tibetan, and Yugur people inherited more than 10% West Eurasian ancestry, much higher than that of Salar and Tu people (<7%). Hence, the difference in the proportion of West Eurasian ancestry has primarily contributed to the genetic divergence of geographically close Northwest Chinese populations. The signatures of natural selection were identified in genes associated with cardiovascular system diseases or lipid metabolism related to triglyceride levels (e.g., PRIM2, PDE4DIP, NOTCH2, DDAH1, GALNT2, and MLIP) and developmental and neurogenetic diseases (e.g., NBPFs 8/9/20/25P, etc.). Moreover, the EPAS1 gene, a transcription factor regulating hypoxia response, showed relatively high PBS values in our studied groups. The sex-biased admixture history, in which the West Eurasian ancestry was introduced primarily by males, was identified in Dongxiang, Tibetan, and Yugur populations. We determined that the eastern-western admixture occurred [~]783-1131 years ago, coinciding with the intensive economic and cultural exchanges during the historic Trans-Eurasian cultural exchange era.

genomics↗

bioRxiv2023

Exposure to high-sugar diet induces transgenerational changes in sweet sensitivity and feeding behavior via H3K27me3 reprogramming

Human health is facing a host of new threats linked to unbalanced diets, including high sugar diet (HSD), which contributes to the development of both metabolic and behavioral disorders. Studies have shown that diet-induced metabolic dysfunctions can transmit to multiple generations of offspring and exert long-lasting health burden. Meanwhile, whether and how diet-induced behavioral abnormalities can be transmitted to the offspring remain largely unclear. Here, we showed that ancestral HSD exposure suppressed sweet sensitivity and feeding behavior in the offspring in Drosophila. These behavioral deficits were transmitted through the maternal germline and companied by the enhancement of H3K27me3 modifications. PCL-PRC2 complex, a major driver of H3K27 trimethylation, was upregulated by ancestral HSD exposure, and disrupting its activity eliminated the transgenerational inheritance of sweet sensitivity and feeding behavior deficits. Elevated H3K27me3 inhibited the expression of a transcriptional factor Cad and suppressed sweet sensitivity of the sweet-sensing gustatory neurons, reshaping the sweet perception and feeding behavior of the offspring. Taken together, we uncovered a novel molecular mechanism underlying behavioral abnormalities across multiple generations of offspring upon ancestral HSD exposure, which would contribute to the further understanding of long-term health risk of unbalanced diet.

neuroscience↗

bioRxiv2023

Differentiated genomic footprints and connections inferred from 440 Hmong-Mien genomes suggest their isolation and long-distance migration

BackgroundThe underrepresentation of Hmong-Mien (HM) people in Asian genomic studies has hindered our comprehensive understanding of population history and human health. South China is an ethnolinguistically diverse region and indigenously settled by ethnolinguistically diverse HM, Austroasiatic (AA), Tai-Kadai (TK), Austronesian (AN), and Sino-Tibetan (ST) people, which is regarded as East Asias initial cradle of biodiversity. However, previous fragmented genetic studies have only presented a fraction of the landscape of genetic diversity in this region, especially the lack of haplotype-based genomic resources. The deep characterization of demographic history and natural-selection-relevant architecture in HM people was necessary. ResultsWe comprehensively reported the population-specific genomic resources and explored the fine-scale genetic structure and adaptative features inferred from the high-density SNP data in 440 individuals from 34 ethnolinguistic populations, including previously unreported She. We identified solid genetic differentiation between inland (Miao/Yao) and coastal (She) southern Chinese HM people, and the latter obtained more gene flow from northern East Asians. Multiple admixture models further confirmed that extensive gene flow from surrounding ST, TK, and AN people entangled in forming the gene pool of coastal southeastern East Asian HM people. Population genetic findings of isolated shared unique ancestral components based on the sharing alleles and haplotypes deconstructed that HM people from Yungui Plateau carried the breadth of genomic diversity and previously unknown genetic features. We identified a direct and recent genetic connection between Chinese and Southeast Asian HM people as they shared the most extended IBD fragments, supporting the long-distance migration hypothesis. Uniparental phylogenetic topology and Network relationship reconstruction found ancient uniparental lineages in southwestern HM people. Finally, the population-specific biological adaptation study identified the shared and differentiated natural-selection signatures among inland and coastal HM people associated with physical features and immune function. The allele frequency spectrum (AFS) of clinical cancer susceptibility alleles and pharmacogenomic genes showed significant differences between HM and northern Chinese people. ConclusionsOur extensive genetic evidence combined with the historic documents supported the view that ancient HM people originated in Yungui regions associated with ancient Three-Miao tribes descended from the ancient Daxi-Qujialing-Shijiahe people. And then, some recently rapidly migrated to Southeast Asia, and some culturally dispersed eastward and mixed respectively with Southeast Asian indigenes, coastal Liangzhu-related ancient populations, and incoming southward Sino-Tibetan people. Generally, complex population migration, admixture, and adaptation history contributed to their specific patterns of non-coding or disease-related genetic variations.

genetics↗

bioRxiv2022

Treatment of prostate cancer with CD46 targeted 225Ac alpha particle radioimmunotherapy

Radiopharmaceutical therapy is changing the standard of care in prostate cancer (PCa) and other malignancies. We previously reported high CD46 expression in PCa and developed an antibody-drug conjugate and immunoPET agent based on the YS5 antibody, which targets a tumor-selective CD46 epitope. Here, we present the preparation, preclinical efficacy, and toxicity evaluation of [225Ac]DOTA-YS5, a radioimmunotherapy agent based on the YS5 antibody. Our radiolabeled antibody retains binding efficacy and shows a high tumor to background ratio in PCa xenografts. Furthermore, we show that radiolabeled antibody was able to suppress the growth of cell-derived and patient-derived xenografts, including PSMA-positive and deficient models. Nephrotoxicity, not seen at low radioactive doses, is evident at higher radioactivity dose levels, likely due to redistribution of daughter isotope 213Bi. Overall, this preclinical study confirms that [225Ac]DOTA-YS5 is a highly effective treatment and suggests feasibility for clinical translation of CD46 targeted radioligand therapy in PCa.

cancer biology↗

bioRxiv2022

Heat and humidity sensors that alert mosquitoes to nearby human hosts

Mosquito-borne diseases sicken >500,000,000 people annually, killing >500,0001. Mosquito host-seeking is guided by multiple host-associated cues, which combine to drive blood feeding in a manner that remains poorly understood2,3. While heat is a powerful mosquito attractant, recent studies indicate that disruption of heat seeking has little impact on host detection by the malaria vector Anopheles gambiae4, suggesting other cues act alongside heat in the complex sensory environment of a human host. Here we show mosquitoes require Ir93a (an Ionotropic Receptor5) to maintain attraction to a human host and feed on warmed blood. Using Ir93a, we uncover the previously uncharacterized mosquito hygrosensory system, and show Ir93a is required for humidity detection by humidity sensors (hygrosensors) as well as temperature detection by thermosensors, and for attraction to each stimulus. These findings indicate that hygrosensation and thermosensation function in parallel, driving host proximity detection in response to the overlapping heat and humidity gradients humans produce6,7. These host cue sensors appear to have arisen by co-opting existing sensors of physical cues rather than de novo, as Ir93a-dependent thermo- and hygro-sensors support physiological homeostasis in non-blood-feeding insects8-11. While Ir93a is conserved among arthropods, reliance on heat and humidity evolved independently in multiple blood-feeding lineages, suggesting multiple, vector-specific implementations of this common host-seeking strategy.

neuroscience↗

bioRxiv2022

An overlapped natural antisense lncRNA FCER1A-AS controls anaphylactic reaction by promoting FcϵRIα expression

Functioned as -subunit of the high-affinity immunoglobulin E receptor (Fc{varepsilon} RI), Fc{varepsilon} RI plays a central role in the pathogenesis of Ig-E-mediated allergy and other IgE-related disorders. Fc{varepsilon} RI is normally expressed only in limited spectrum of cells like basophils and mast cells, but the mechanism of controlling Fc{varepsilon} RI expression in these cells is less well understood. In this study, we found fully overlapped natural antisense transcript (NATs) of Fc{varepsilon} RI (FCER1A-AS) is co-expressed with cognate sense transcript (FCER1A-S) in IL-3 induced Fc{varepsilon} RI-expressing cells or in high Fc{varepsilon} RI-expressing cell line MC/9. When FCER1A-AS is selectively knocked down by CRISPR/RfxCas13d (CasRx) approach in MC/9, expression of mRNA and proteins of FCER1A-S is also markedly decreased. Furthermore, deficiency of FCER1A-AS along with lack of FCER1A-S expression is found in two different lines of gene-targeted mice in which FCER1A locus is disturbed at different sites. More importantly, the FCER1A-AS-deficient homozygous mice display similarly diminished anaphylactic reaction as FCER1A gene knockout mice. Thus, we uncovered in this investigation that the expression of FCER1A-S is positively regulated by co-expressed fully overlapped antisense transcript.

immunology↗

bioRxiv2022

4D Cell-Condensate Bioprinting

4D bioprinting techniques that facilitate formation of shape-changing scaffold-free cell condensates with prescribed geometries have yet been demonstrated. Here, a simple yet novel 4D bioprinting approach is presented that enables formation of a shape-morphing cell condensate-laden bilayer system comprised of an actuation layer and a cell condensate-supporting microgel (MG) layer. The strategy produces scaffold-free cell condensates which morph over time into predefined complex shapes. With a sequential printing (i.e., MG printing first onto the preformed actuation hydrogel layer and cell-only printing inside the pre-printed MG construct second), cell condensate-laden bilayers with specific geometries are readily fabricated and can be further UV-crosslinked to form strong interlayer adhesion. Since the bilayers have tunable deformability and MG degradation can be tailored, this enables controllable morphological transformations and on-demand liberation of cell condensates. With this system, large cell condensate-laden constructs with various complex shapes were obtained through predefined conformational conversions. As a proof-of-concept study, the formation of the letter "C" and helix-shaped robust cartilage-like tissues differentiated from human mesenchymal stem cells (hMSCs) was demonstrated. This new system brings about a new versatile 4D bioprinting platform idea that is anticipated to broaden and facilitate the applications of cell condensation-based 4D bioprinting.

bioengineering↗

bioRxiv2022

MicroRNA-155 regulates osteogenesis and bone mass phenotype via targeting S1PR1 gene

MicroRNA-155 (miR155) is overexpressed in various inflammatory diseases and cancer, in which bone resorption and osteolysis are frequently observed. However, the role of miR155 on osteogenesis and bone mass phenotype is still unknown. Here, we report a low bone mass phenotype in the long bone of miR155-Tg mice compared with control mice. In contrast, miR155-KO mice showed a high bone mass phenotype. miR155-KO mice showed robust bone regeneration in the ectopic and orthotopic model, but miR155-Tg mice showed compromised bone regeneration compared with the control mice. Similarly, the osteogenic differentiation potential of bone marrow stromal stem cells (BMSCs) from miR155-KO mice was robust and miR155-Tg was compromised compared with that of control mice. Moreover, miR155 knockdown in BMSCs from control mice showed higher osteogenic differentiation potential, supporting the results from miR155-KO mice. TargetScan analysis predicted S1PR1 as a target gene of miR155, which was further confirmed by luciferase assay and miR155 knockdown. S1PR1 overexpression in BMSCs robustly promoted osteogenic differentiation without affecting cell viability and proliferation. Thus, miR155 showed a catabolic effect on osteogenesis and bone mass phenotype via interaction with the S1PR1 gene, suggesting inhibition of miR155 as a potential strategy for bone regeneration and bone defect healing.

cell biology↗

bioRxiv2021

Global cerebrospinal fluid circulation mapping using gold nanoparticle enhanced X-ray microtomography reveals region-specific brain and spinal cord CSF pathways

Cerebrospinal fluid (CSF) movement within the brain interstitium is essential for the development and functioning of the brain. However, the interstitium has largely been thought of as a single entity through which CSF circulates, and it is not known whether specific cell populations within the CNS preferentially interact with CSF. Here, we developed a novel technique for CSF tracking, gold nanoparticle enhanced X-ray microtomography, to achieve micrometer-scale resolution visualization of CSF pathways during development. Using this method and subsequent histological analysis, we map global CSF pathways and present novel particle size-dependent circulation patterns through the CNS. We identify an intraparenchymal CSF circulation that targets stem cell-rich and cholinergic neuronal populations. CSF solute distribution to these areas is mediated by CSF flow along projections from the basal cisterns which is altered in posthemorrhagic hydrocephalus. Our study uncovers region-specific patterns in a biologically driven CSF circulation that has implications for normal brain development and the pathophysiology of hydrocephalus and neurodegenerative disorders.

neuroscience↗