Biology subjects

Jin, Y.

Publications and source records attributed to Jin, Y..

At least 145 records · Page 8Linked to original sources

bioRxiv2023

Cell-free multi-omics analysis reveals tumor status-informative signatures in gastrointestinal cancer patients' plasma

During cancer development, hosts tumorigenesis and immune signals are released to and informed by circulating molecules, like cell-free DNA (cfDNA) and RNA (cfRNA) in blood. However, these two kinds of molecules are still not systematically compared in gastrointestinal cancer. Here, we profiled 4 types of cell-free omics data from colorectal and stomach cancer patients, and assayed 15 types of genomic, epi-genomic, and transcriptomic variations. First, we demonstrated that the multi-omics data were more capable of detecting cancer genes than the single-omics data, where cfRNAs were more sensitive and informative than cfDNAs in terms of detection ratio, variation type, altered number, and enriched functional pathway. Moreover, we revealed several peripheral immune signatures that were suppressed in cancer patients and originated from specific circulating and tumor-microenvironment cells. Particularly, we defined a {gamma}{delta}-T-cell score and a cancer-associated-fibroblast (CAF) score using the cfRNA-seq data of 143 cancer patients. They were informative of clinical status like cancer stage, tumor size, and survival. In summary, our work reveals the cell-free multi-molecular landscape of colorectal and stomach cancer, and provides a potential monitoring utility in blood for the personalized cancer treatment.

systems biology↗

bioRxiv2023

Identification of common sequence motifs shared exclusively among selectively packed exosomal pathogenic microRNAs during rickettsial infections

We previously reported that microRNA (miR)23a and miR30b are selectively sorted into rickettsia-infected, endothelial cell-derived exosomes (R-ECExos). Yet, the mechanism remains unknown. The number of cases of spotted fever rickettsioses has been increasing in recent years, and infections with these bacteria cause life-threatening diseases by targeting brain and lung tissues. Therefore, the aim of the present study is to continue to dissect the molecular mechanism underlying R-ECExos-induced barrier dysfunction of normal recipient microvascular endothelial cells (MECs), depending on their exosomal RNA cargos. Rickettsiae are transmitted to human hosts by the bite of an infected tick into the skin. In the present study we demonstrate that treatment with R-ECExos, which were derived from spotted fever group R parkeri infected human dermal MECs, induced disruptions of the paracellular adherens junctional protein VE-cadherin and breached the paracellular barrier function in recipient pulmonary MECs (PMECs) in an exosomal RNA-dependent manner. Similarly, we did not detect different levels of miRs in parent dermal MECs following rickettsial infections. However, we demonstrated that the microvasculopathy-relevant miR23a-27a-24 cluster and miR30b are selectively enriched in R-ECExos. Bioinformatic analysis revealed that common sequence motifs are shared exclusively among the exosomal, selectively-enriched miR23a cluster and miR30b at different levels. Taken together, these data warrant further functional identification and characterization of a single, bipartition, or tripartition among ACA, UCA, and CAG motifs that guide recognition of microvasculopathy-relevant miR23a-27a-24 and miR30b, and subsequently results in their selective enrichments in R-ECExos.

molecular biology↗

bioRxiv2022

High Sensitivity Top-down Proteomics Captures Single Muscle Cell Heterogeneity in Large Proteoforms

Single-cell proteomics has emerged as a powerful method to characterize cellular phenotypic heterogeneity and the cell-specific functional networks underlying biological processes. However, significant challenges remain in single-cell proteomics for the analysis of proteoforms arising from genetic mutations, alternative splicing, and post-translational modifications. Herein, we have developed a highly sensitive functionally integrated top-down proteomics method for the comprehensive analysis of proteoforms from single cells. We applied this method to single muscle fibers (SMFs) to resolve their heterogeneous functional and proteomic properties at the single cell level. Notably, we have detected single-cell heterogeneity in large proteoforms (>200 kDa) from the SMFs. Using SMFs obtained from three functionally distinct muscles, we found fiber-to-fiber heterogeneity among the sarcomeric proteoforms which can be related to the functional heterogeneity. Importantly, we reproducibly detected multiple isoforms of myosin heavy chain (~223 kDa), a motor protein that drives muscle contraction, with high mass accuracy to enable the classification of individual fiber types. This study represents the first "single-cell" top-down proteomics analysis that captures single muscle cell heterogeneity in large proteoforms and establishes a direct relationship between sarcomeric proteoforms and muscle fiber types, highlighting the potential of top-down proteomics for uncovering the molecular underpinnings of cell-to-cell variation in complex systems. Significance StatementSingle-cell technologies are revolutionizing biology and molecular medicine by allowing direct investigation of the biological variability among individual cells. Top-down proteomics is uniquely capable of dissecting biological heterogeneity at the intact protein level. Herein, we develop a highly sensitive single-cell top-down proteomics method to reveal diverse molecular variations in large proteins (>200 kDa) among individual single muscle cells. Our results both reveal and characterize the differences in protein post-translational modifications and isoform expression possible between individual muscle cells. We further integrate functional properties with proteomics and accurately measure myosin isoforms for individual muscle fiber type classification. Our study highlights the potential of top-down proteomics for understanding how single-cell protein heterogeneity contributes to cellular functions.

biochemistry↗

bioRxiv2022

Discovery and molecular basis of chloride as an allosteric activator and catalytic inhibitor for Class-D lactamases.

Oxacillinase (OXA)-48-like carbapenemases are epidemic class D {beta}-lactamases in Enterobacterales, resulting in high mortality. Though the chemical mechanism has been clearly established, for decades, the link between the biphasic kinetic behaviour of these enzymes, which significantly impacts antibiotic efficacy, and the state of carbamylated lysine has been elusive. Here, substituting N-carbamylated lysine73 with a chemically-stable N-acetyl lysine allows us to prove the origin of catalytic inhibition is not decarbamylation and enables us to capture an unprecedented inactive acyl-intermediate wedged in place by a chloride ion against the conserved residue arginine250. We here identify chloride as a "Janus effector" acting by allosteric activation of the burst phase and inhibition of the steady-state for a series of {beta}-lactam substrates in kinetic assays. Chloride ions are necessarily present in both laboratory and clinical OXA activity assays and their inseparable role is now identified. Our finding suggests a new direction for the discovery of next-generation antibiotics specific for {beta}-lactamases of Class D.

biochemistry↗

bioRxiv2022

Starfysh reveals heterogeneous spatial dynamics in the breast tumor microenvironment

Spatially-resolved gene expression profiling provides valuable insight into tissue organization and cell-cell crosstalk; however, spatial transcriptomics (ST) lacks single-cell resolution. Current ST analysis methods require single-cell RNA sequencing data as a reference for a rigorous interpretation of cell states and do not utilize associated histology images. Significant sample variation further complicates the integration of ST datasets, which is essential for identifying commonalities across tissues or altered cellular wiring in disease. Here, we present Starfysh, the first comprehensive computational toolbox for joint modeling of ST and histology data, dissection of refined cell states, and systematic integration of multiple ST datasets from complex tissues. Starfysh uses an auxiliary deep generative model that incorporates archetypal analysis and any known cell state markers to avoid the need for a single-cell-resolution reference in characterizing known or novel tissue-specific cell states. Additionally, Starfysh improves the characterization of spatial dynamics in complex tissues by leveraging histology images and enables the comparison of niches as spatial "hubs" across tissues. Integrative analysis of primary estrogen receptor-positive (ER+) breast cancer, triple-negative breast cancer (TNBC), and metaplastic breast cancer (MBC) tumors using Starfysh led to the identification of heterogeneous patient- and disease-specific hubs as well as a shared stromal hub with varying spatial orientation. Our results show the ability to delineate the spatial co-evolution of tumor and immune cell states and their crosstalk underlying intratumoral heterogeneity in TNBC and revealed metabolic reprogramming shaping immunosuppressive hubs in aggressive MBC. Starfysh is publicly available (https://github.com/azizilab/starfysh).

bioinformatics↗

bioRxiv2022

Modulation of the microhomology-mediated end joining pathway suppresses large deletions and enhances homology-directed repair following CRISPR-Cas9-induced DNA breaks

CRISPR-Cas9, an efficient genome editing tool, has been widely used in research and holds great promise in the clinic. However, large unintended rearrangements of the genome occur frequently after CRISPR-Cas9 editing and their potential risk cannot be ignored. In this study, we detected large deletions (LDs) induced by CRISPR-Cas9 in human embryonic stem cells (hESCs) and found the microhomology end joining (MMEJ) DNA repair pathway plays a predominant role in LD. We genetically targeted PARP1, RPA, POLQ and LIG3, which play critical roles in MMEJ, during CRISPR-Cas9 editing. By analyzing LD events in two independent gene loci, CD9 and PIGA, using flow cytometry and long-read individual molecule sequencing (IDMseq), we showed that knocking down PARP1 and LIG3 does not alter the frequency of Cas9-induced LD, while knocking down or inhibiting POLQ dramatically reduces LD. Knocking down RPA increases LD frequency, and overexpression of RPAs consistently reduces LD frequency. Interestingly, small-molecule inhibition of POLQ and delivery of recombinant RPA proteins also dramatically increase the efficiency of homology-directed repair (HDR). In conclusion, RPA and POLQ play opposite roles in Cas9-induced LD, modulation of POLQ and RPA can reduce LD and improve HDR, thus holding promise for safe and precise genome editing.

molecular biology↗

bioRxiv2022

Transcription-independent hold of the G1/S transition is exploited to cope with DNA replication stress

RB1 (retinoblastoma) members control the G1/S commitment as transcriptional repressors in eukaryotic cells. Here we uncover that an extra copy of RB1 equivalent (WHI7 or WHI5) is sufficient to bypass the indispensability of the central genomic checkpoint kinases Mec1ATR-Rad53CHK1 in Saccharomyces cerevisiae. Mec1-Rad53 directly phosphorylate Whi7/5, antagonizing their nuclear export or protein turnover upon replication stress. Through in vitro reconstitution, we show that Whi7 C-terminus directly binds and hinders S-CDK-Cks1 from processively phosphorylating Sic1. By microfluidic single-cell real-time quantitative imaging, we demonstrate that both Whi7 and Whi5 are required to flatten the degradation curve of the major S-CDK inhibitor Sic1 in vivo. These findings reveal an eclipsed transcription-independent role of Whi7 homologs, which is highlighted by genome integrity checkpoints to hold the G1/S transition instantly as a rapid response to unforeseeable replication threats. Key pointsO_LIWhi7 overexpression bypasses the essential function of Mec1 and Rad53 in a transcription-independent way. C_LIO_LIWhi7 is stabilized by checkpoint-mediated phosphorylation. C_LIO_LIWhi7 binds and hinders S-CDK-Cks1 from multi-phosphorylation of Sci1, thereby prolonging Sic1 degradation and G1/S transition. C_LI

molecular biology↗

bioRxiv2022

Towards increased accuracy and reproducibility in SARS-CoV-2 next generation sequence analysis for public health surveillance

During the COVID-19 pandemic, SARS-CoV-2 surveillance efforts integrated genome sequencing of clinical samples to identify emergent viral variants and to support rapid experimental examination of genome-informed vaccine and therapeutic designs. Given the broad range of methods applied to generate new viral genomes, it is critical that consensus and variant calling tools yield consistent results across disparate pipelines. Here we examine the impact of sequencing technologies (Illumina and Oxford Nanopore) and 7 different downstream bioinformatic protocols on SARS-CoV-2 variant calling as part of the NIH Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV) Tracking Resistance and Coronavirus Evolution (TRACE) initiative, a public-private partnership established to address the COVID-19 outbreak. Our results indicate that bioinformatic workflows can yield consensus genomes with different single nucleotide polymorphisms, insertions, and/or deletions even when using the same raw sequence input datasets. We introduce the use of a specific suite of parameters and protocols that greatly improves the agreement among pipelines developed by diverse organizations. Such consistency among bioinformatic pipelines is fundamental to SARS-CoV-2 and future pathogen surveillance efforts. The application of analysis standards is necessary to more accurately document phylogenomic trends and support data-driven public health responses.

bioinformatics↗

bioRxiv2022

Functional Integration of 3D-Printed Cerebral Cortical Tissue into a Brain Lesion

Engineering human tissue with diverse cell types and desired cellular architectures and functions is a considerable challenge. The cerebral cortex, which has a layered cellular architecture composed of layer-specific neurons organised into vertical columns, delivers higher cognition through intricately wired neural circuits. However, current tissue engineering approaches cannot produce such structures. Here, we use a droplet printing technique to fabricate tissues comprising simplified cerebral cortical columns. Human induced pluripotent stem cells (hiPSCs) were differentiated into upper- and deep-layer neural progenitors, which were then printed to form cerebral cortical tissues with a two-layer organization. The tissues showed layer-specific biomarker expression and developed an integrated network of processes. Implantation of the printed cortical tissues into mouse brain explants resulted in substantial implant-host integration across the tissue boundaries as demonstrated by the projection of processes, the migration of neurons and the appearance of correlated Ca2+ signals. The approach we have developed might be used for the evaluation of drugs and nutrients that promote tissue integration. Importantly, our approach might be applied in personalised implantation treatments that restore the cellular structure and function of a damaged brain by using 3D tissues derived from a patients own iPSCs.

bioengineering↗

bioRxiv2022

HSPB1 facilitates chemoresistance through inhibiting ferroptotic cancer cell death and regulating NF-κB signaling pathway in breast cancer

Chemoresistance is one of the major causes of therapeutic failure and poor prognosis for breast cancer patients, especially for triple-negative breast cancer patients. However, the underlying mechanism remains elusive. Here, we identified novel functional roles of heat shock protein beta-1 (HSPB1), regulating the chemoresistance and ferroptotic cell death in breast cancer. Based on TCGA and GEO databases, HSPB1 expression was upregulated in breast cancer tissues and associated with poor prognosis of breast cancer patients, which was considered as an independent prognostic factor for breast cancer. Functional assays revealed that HSPB1 could promote cancer growth and metastasis in vitro and in vivo. Furthermore, HSPB1 facilitated doxorubicin resistance through protecting breast cancer cells from drug-induced ferroptosis. Mechanistically, HSPB1 could bind with Ik{beta}- and promote its ubiquitination-mediated degradation, leading to increased nuclear translocation and activation of NF-{kappa}B signaling. In addition, HSPB1 overexpression led to enhanced secretion of IL6, which further facilitated breast cancer progression. These findings revealed that HSPB1 upregulation might be a key driver to progression and chemoresistance through regulating ferroptosis in breast cancer, while targeting HSPB1 could be an effective strategy against breast cancer.

cancer biology↗

bioRxiv2022

Multi-omics of Circular RNAs and Their Responses to Hormones in Moso Bamboo (Phyllostachys edulis)

Circular RNAs are endogenous non-coding RNAs with covalently closed structures, which have important functions in plants. However, their biogenesis, degradation, and function upon treatment with gibberellins (GA) and auxins (NAA) remain unknown. Here, we systematically identified and characterized expression patterns, evolutionary conservation, genomic features, and internal structures of circRNAs using RNase R-treated libraries from moso bamboo (Phyllostachys edulis) seedlings. Moreover, we investigated the biogenesis of circRNAs dependent on both cis- and trans-regulation. We determined details regarding the function of circRNAs, including their roles in regulating microRNA-related genes and modulating the alternative splicing of their linear counterparts. Importantly, we developed a customized degradome sequencing approach to detect microRNA-mediated cleavage of circRNAs. Finally, we present a comprehensive view of the participation of circRNAs in the regulation of hormone metabolism upon treatment of bamboo seedlings with gibberellins (GA) and auxins (NAA). Collectively, our study uncovers important features of circRNAs including overall characteristics, biogenesis, function, and microRNA-mediated degradation of circRNAs in moso bamboo.

plant biology↗

bioRxiv2022

Rapid reversible osmoregulation of cytoplasmic biomolecular condensates of human interferon-α-induced antiviral MxA GTPase

Cellular and tissue-level edema is a common feature of acute viral infections such as covid-19, and of many hyponatremic hypoosmolar disorders. However, there is little understanding of the effects of cellular edema on antiviral effector mechanisms. We previously discovered that cytoplasmic human MxA, a major antiviral effector of Type I and III interferons against several RNA- and DNA-containing viruses, existed in the cytoplasm in phase-separated membraneless biomolecular condensates of varying sizes and shapes. In this study we investigated how hypoosmolar conditions, mimicking cellular edema, might affect the structure and antiviral function of MxA condensates. Cytoplasmic condensates of both IFN--induced endogenous MxA and of exogenously expressed GFP-MxA in human A549 lung and Huh7 hepatoma cells rapidly disassembled within 1-2 min when cells were exposed to hypotonic buffer ([~] 40-50 mOsm), and rapidly reassembled into new structures within 1-2 min of shifting of cells to isotonic culture medium ([~] 330 mOsm). MxA condensates in cells continuously exposed to culture medium of moderate hypotonicity (in the range one-fourth, one-third or one-half isotonicity; range 90-175 mOsm) first rapidly disassembled within 1-3 min, and then, in most cells, spontaneously reassembled 7-15 min later into new structures. Condensate reassembly, whether induced by isotonic medium or occurring spontaneously under continued moderate hypotonicity, was preceded by "crowding" of the cytosolic space by large vacuole-like dilations (VLDs) derived from internalized plasma membrane. Remarkably, the antiviral activity of GFP-MxA against vesicular stomatitis virus survived hypoosmolar disassembly. Overall, the data highlight the exquisite sensitivity of MxA condensates to rapid reversible osmoregulation.

biochemistry↗

bioRxiv2022

Longitudinal neural and vascular recovery following ultraflexible neural electrode implantation in aged mice

Flexible neural electrodes improve the recording longevity and quality of individual neurons by promoting tissue-electrode integration. However, the intracortical implantation of flexible electrodes inevitably induces tissue damage. Understanding the longitudinal neural and vascular recovery following the intracortical implantation is critical for the ever-growing applications of flexible electrodes in both healthy and disordered brains. Aged animals are of particular interest because they play a key role in modeling neurological disorders, but their tissue-electrode interface remains mostly unstudied. Here we integrate in-vivo two-photon imaging and electrophysiological recording to determine the time-dependent neural and vascular dynamics after the implantation of ultraflexible neural electrodes in aged mice. We find heightened angiogenesis and vascular remodeling in the first two weeks after implantation, which coincides with the rapid increase in local field potentials and unit activities detected by electrophysiological recordings. Vascular remodeling in shallow cortical layers preceded that in deeper layers, which often lasted longer than the recovery of neural signals. By six weeks post-implantation vascular abnormalities had subsided, resulting in normal vasculature and microcirculation. Putative cell classification based on firing pattern and waveform shows similar recovery time courses in fast-spiking interneurons and pyramidal neurons. These results elucidate how structural damages and remodeling near implants affecting recording efficacy, and support the application of ultraflexible electrodes in aged animals at minimal perturbations to endogenous neurophysiology.

neuroscience↗

bioRxiv2022

The solution path of the Li-Stephens haplotype copying model

The Li-Stephens (LS) haplotype copying model forms the basis of a number of important statistical inference procedures in genetics. LS is a probabilistic generative model which supposes that a sampled chromosome is an imperfect mosaic of other chromosomes found in a population. In the frequentist setting which is the focus of this paper, the output of LS is a "copying path" through chromosome space. The behavior of LS depends crucially on two user-specified parameters,{theta} and{rho} , which are respectively interpreted as the rates of mutation and recombination. However, because LS is not based on a realistic model of ancestry, the precise connection between these parameters and the biological phenomena they represent is unclear. Here, we offer an alternative perspective, which considers{theta} and{rho} as tuning parameters, and seeks to understand their impact on the LS output. We derive an algorithm which, for a given dataset, efficiently partitions the ({theta}, {rho}) plane into regions where the output of the algorithm is constant, thereby enumerating all possible solutions to the LS model at one go. We extend this approach to the "diploid LS" model commonly used for phasing. We demonstrate the usefulness of our method by studying the effects changing of{theta} and{rho} when using LS for common bioinformatic tasks. Our findings indicate that using the conventional (i.e., population-scaled) values for{theta} and{rho} produces near optimal results for imputation, but may systematically inflate switch error in the case of phasing diploid genotypes.

genetics↗

bioRxiv2022

Type 17 Follicular Helper T (Tfh17) Cells are Superior for Memory Maintenance

A defining feature of successful vaccination is the ability to induce long-lived antigen- specific memory cells. Follicular helper T (Tfh) cells specialize in providing help to B cells in mounting protective humoral immunity in infection and after vaccination. Memory Tfh cells that retain the CXCR5 expression can confer protection through enhancing humoral response upon antigen re-exposure but how they are maintained is poorly understood. CXCR5+ memory Tfh cells in human blood are divided into Tfh1, Tfh2 and Tfh17 cells by the expression of chemokine receptors CXCR3 and CCR6 associated with Th1 and Th17 respectively. Here, we developed a new method to induce Tfh1, Tfh2 and Tfh17-like (iTfh1, iTfh2 and iTfh17) cells in vitro. Although all three iTfh subsets efficiently support antibody responses in recipient mice with immediate immunization, iTfh17 cells are superior to iTfh1 and iTfh2 cells in supporting antibody response to a later immunization after extended resting in vivo to mimic memory maintenance. Notably, the counterpart human Tfh17 cells are selectively enriched in CCR7+ central memory Tfh (TfhCM) with survival and proliferative advantages. Furthermore, the analysis of multiple human cohorts that received different vaccines for HBV, influenza virus, tetanus toxin or measles revealed that vaccine-specific Tfh17 cells outcompete Tfh1 or Tfh2 cells for the persistence in memory phase. Therefore, the complementary mouse and human results showing the advantage of Tfh17 cells in maintenance and memory function supports the notion that Tfh17-induced immunization might be preferable in vaccine development to confer long-term protection.

immunology↗

bioRxiv2022

Generation of cardiomyocytes from human induced pluripotent stem cells resembling atrial cells with ability to respond to adrenoceptor agonists

Cardiovascular disease is the leading cause of global mortality and morbidity. Cardiac dysrhythmias contribute significantly to this disease burden. Atrial fibrillation (AF) is the most common chronic dysrhythmia. Human induced pluripotent stem cell-derived atrial cardiomyocytes (hiPSC-AMs) present an exciting new model for AF but currently fail to reach maturity and so are limited in translational potential currently. We report a new approach using a combination of Gremlin 2 and retinoic acid treatment of human iPSCs for generating cardiomyocytes resembling atrial cells. More than 40% of myocytes generated by this approach showed rod-shaped morphology, expression of cardiomyocyte proteins (including RyR2 receptors, a-actinin-2, F-actin) and typically a striated appearance, all of which were broadly similar to the characteristics of adult atrial myocytes. Isolated myocytes were electrically quiescent until stimulated to fire action potentials with an atrial myocyte profile and an amplitude of approximately 100 mV, arising from a resting potential of approximately -70 mV. Single-cell RNA sequence (scRNASeq) analysis showed a high level of expression of several atrial specific transcripts including NPPA, MYL7, HOXA3, SLN, KCNJ4, KCNJ5 and KCNA5. Amplitudes of calcium transients recorded from spontaneously beating cultures were increased by the stimulation of -adrenoceptors (activated by phenylephrine and blocked by prazosin) or {beta}-adrenoceptors (activated by isoproterenol and blocked by CGP20712A). Thus, our new method provides an efficient approach for differentiating human atrial myocytes with mature characteristics from hiPSCs. This preparation will be very useful for studying signalling pathways in human atrial myocytes, and provides a valuable model for investigating atrial fibrillation and drug discovery.

bioengineering↗

bioRxiv2022

Amyloid-β Oligomers Serve as Nucleation Sites for α-Synuclein Aggregation

An increasing number of cases where amyloids of different proteins are found in the same patient are being reported. This observation complicates diagnosis and clinical intervention. Amyloids of the amyloid-{beta} peptide or the protein -synuclein are traditionally considered hallmarks of Alzheimers and Parkinsons diseases, respectively. However, the co-occurrence of amyloids of these proteins has also been reported in patients diagnosed with either disease. Here, we show that soluble species containing amyloid-{beta} can induce the aggregation of -synuclein. Fibrils formed under these conditions are solely composed of -synuclein to which amyloid-{beta} can be found associated, but not as part of the core of the fibrils. Importantly, by global kinetic analysis, we found that the aggregation of -synuclein under these conditions occurs via heterogeneous primary nucleation, triggered by soluble aggregates containing amyloid-{beta}.

biochemistry↗

bioRxiv2022

Basis for antibody- and hormone-mediated activation of TSHR in Graves' disease

Thyroid stimulating hormone (TSH), through activation of its G protein-coupled receptor TSHR, controls the synthesis of thyroid hormone (TH), an essential metabolic hormone. Aberrant signaling of TSHR by autoantibodies causes Graves disease and hypothyroidism that affect millions of patients worldwide. Here we report the active structures of TSHR with TSH and an activating autoantibody M22, both bound to an allosteric agonist ML-109, as well as an inactive TSHR structure with inhibitory antibody K1-70. Both TSH and M22 push the extracellular domain (ECD) of TSHR into the upright active conformation. In contrast, K1-70 blocks TSH binding and is incapable of pushing the ECD to the upright conformation. Comparisons of the active and inactive structures of TSHR with those of the luteinizing hormone-choriogonadotropin receptor (LHCGR) reveal a universal activation mechanism of glycoprotein hormone receptors, in which a conserved 10-residue fragment (P10) from the hinge C-terminal loop mediated interactions from the receptor ECD to its transmembrane domain. One surprisingly feature is that there are over 15 cholesterols surrounding TSHR, supporting its preferential location in lipid rafts. These structures also highlight a common mechanism for TSH and autoantibody M22 to activate TSHR, thus providing the molecular basis for Graves disease.

molecular biology↗