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Biology subjects

Teng, K.

Publications and source records attributed to Teng, K..

9 recordsLinked to original sources

Endotome as a Source of Human Peri-Aortic Brown Adipocytes

Brown adipocytes (BAs) hold therapeutic promise for obesity and metabolic diseases. While interscapular BAs derive from Pax3+/Myf5+ dermomyotome, peri-aortic BAs are inferred from an unknown Pax3+/Myf5- somitic origin. Here, we identify human endotome as an MYF5-independent source of peri-aortic BAs. Through interrogating public mouse organogenesis and in-house human trunk embryoid single-cell data, we show that the early endotome cells are MYF5-independent and are primed by TGF-{beta}-induced epithelial-to-mesenchymal transition. Mechanistically, endotome-to-BA specification requires sequential BMP inhibition and Wnt activation. This roadmap results in UCP1-expressing and metabolically active BAs that transcriptionally resemble in vivo peri-aortic BAT. The multipotent endotome cells also give rise to vascular smooth muscle and endothelial cells, offering a self-sufficient source for BAT vasculature. Endotome-derived BAs show accelerated differentiation, reduced heterogeneity, and sustained Wnt activity. Thus, the endotome provides a versatile platform for generating BAs and supporting vasculature, with implications for cell-based therapy and tissue engineering in metabolic disease.

developmental biology↗

Human trunk embryoids with patterned anterior-posterior and dorsal-ventral body axes: utility for understanding human development and disease

Human embryoid models enable mechanistic studies of development and disease. We generated trunk embryoids from human pluripotent stem cells that recapitulate posterior trunk formation at Carnegie stage (CS) 8-10, with patterned anterior-posterior (A-P) and dorsal-ventral (D-V) axes. These self-organizing structures comprise a ventral notochord, dorsal neural tube, floor plate and bilateral somites. Genetic and chemical perturbations of SHH signaling confirmed the notochords central role in D-V patterning. Moreover, VANGL1/2 loss-of-function mutations recapitulated mouse phenotypes, including axial truncation and somite segmentation failure. This model enables detailed study of key developmental events that underlie posterior trunk formation and provides a promising platform for human disease modeling.

developmental biology↗

Aging-associated vacuolation of multi-ciliated cells in the distal mouse oviduct reflects unique cell identity and luminal microenvironment

The female reproductive organs present with the earliest aging characteristics, such as a decline in fertility and estrous cyclicity. While age-related changes in the ovary are well-documented, it is unclear if any age-associated changes occur in the other female reproductive organs, such as the oviduct/fallopian tube. The recent recognition of the distal end of the fallopian tube as the tissue of origin of high-grade serous tubal ovarian carcinomas (HGSCs), and that its patient demographic is strongly biased to postmenopausal women, motivated us to investigate age-associated changes in this organ. At the distal end of aged oviducts in mice, we found vacuolated multi-ciliated cells (MCCs) with a severely apically displaced and deformed nucleus. This phenotype was unique to the distal oviduct epithelium -infundibulum (INF) and ampulla (AMP). Ovariectomy did not affect the timeline of MCC vacuolation, suggesting little involvement of ovulation and hormonal regulation. MCC vacuolation was induced in hypoxia or hydroxyurea treatments in in vitro organotypic culture of all oviduct regions, not limited to the INF/AMP epithelium. This suggests high oxygen demand in MCCs, compared to other cell types, and a uniquely stressed INF/AMP epithelial microenvironment in vivo. We found that the blood circulation of INF/AMP depended on the ovarian artery, different from the rest of the oviduct epithelium and its circulation declined along with ovarian activities. We conclude that a decline in local blood circulation and distinct cellular identity of the INF/AMP epithelium caused age-associated MCC vacuolation, reflecting its mild, chronically stressed microenvironment.

physiology↗

The functional impact of 1,570 SNP-accessible missense variants in human OTC

Deleterious mutations in the X-linked gene encoding ornithine transcarbamylase (OTC) cause the most common urea cycle disorder, OTC deficiency. This rare, but highly actionable disease can present with severe neonatal onset in males or with later onset in either sex. Neonatal onset patients appear normal at birth but rapidly develop hyperammonemia, which can progress to cerebral edema, coma and death, outcomes ameliorated by rapid diagnosis and treatment. Existing biochemical assays have limitations, including the sensitivity of the citrulline assays used in newborn screening panels. With prior knowledge of variant pathogenicity, DNA sequence-based diagnostics would provide an alternative screening method. Here, we develop a high throughput functional assay for human OTC and measure the impact of 1,570 variants, 84% of all SNP-accessible missense mutations. Our assay scores agree well with existing clinical significance calls, distinguishing known benign from pathogenic variants and variants with neonatal onset from late-onset disease presentation. Further, use of an intronless expression construct allows us to measure the impact of amino acid changes at splice sites independent of their effect on splicing, thereby separating the contribution of splicing and protein coding changes to aid the analysis of molecular mechanisms underlying pathogenicity. Finally, we assess the utility of our functional data on OTC variant curation by using the current ACMG/AMP guidelines to reclassify variants. Inclusion of our data as PS3/BS3 substantially improves variant interpretation. Thus, our dataset is of high clinical utility and illustrates the power of functional assays to inform interpretation of existing and novel genetic variation.

genetics↗

In vivo CRISPR screens reveal Serpinb9 and Adam2 as regulators of immune therapy response in lung cancer

How the genetic landscape of a tumor governs the tumors response to immunotherapy remains largely elusive. Here, we established a direct in vivo CRISPR/Cas9 gene editing methodology to assess the immune-modulatory capabilities of 573 putative cancer genes associated with altered cytotoxic activity in human cancers. Using KrasG12D- and BrafV600E-driven mouse lung cancer models, we identify Serpinb9 and Adam2 as our top immune suppressive and immune enhancing genes, respectively. Mechanistically, we show that Serpinb9 ablation in KrasG12D- and BrafV600E-mutant lung tumor cells greatly enhances the efficacy of cytotoxic T-cells in vitro and in vivo. ADAM2 is a cancer testis antigen broadly expressed in human cancers such as lung adenocarcinoma (13.9%), renal (74.7%), prostate (72.4%), uterine (28.6%) and invasive breast (9.5%) cancer. In our mouse models, we show that Adam2 expression is induced in KrasG12D- but not BrafV600E-driven murine lung tumors and that its expression is further enhanced by immunotherapy. We show that loss of Adam2 significantly decreases KrasG12D-lung tumor burden but blocks the efficacy of cytotoxic T-cells. Consistently, Adam2 overexpression dramatically increases tumor growth and enhances immunotherapy efficacy. Mechanistically, we find that Adam2s oncogenic function depends on modulating the tumor immune microenvironment by restraining productive type I and type II interferon responses as well as cytokine signaling, reducing the presentation of tumor-associated antigen, and modulating surface expression of several immunoregulatory receptors within Kras-driven lung tumors. Adam2 expression also leads to reduced levels of immune checkpoint inhibitors such as Pd-l1, Lag3, Tigit and Tim3. This reduced exhaustion within the tumor microenvironment may explain why ex vivo expanded and adoptively transferred cytotoxic T-cells show enhanced cytotoxic efficacy against Adam2 overexpressing lung tumors. Together, our study highlights the power of integrating cancer genomic with in vivo CRISPR/Cas9 screens to uncover how cancer-associated genetic alterations control responses to immunotherapies.

cancer biology↗

Loss of epigenetic regulation disrupts lineage integrity, reactivatesmultipotency and promotes breast cancer

Systematically investigating the scores of genes mutated in cancer and discerning real drivers from inconsequential bystanders is a prerequisite for Precision Medicine, but remains challenging. Here, we developed a somatic CRISPR/Cas9 mutagenesis screen to study 215 recurrent long-tail breast cancer genes, which revealed epigenetic regulation as major tumor suppressive mechanism. We report that core or accessory components of the COMPASS histone methylase complex including KMT2C, KDM6A, BAP1 and ASXL2 ("EpiDrivers") cooperate with PIK3CAH1047R to transform mouse and human breast epithelial cells. Mechanistically, we find that Cre-mediated activation of PIK3CAH1047R elicited an aberrant alveolar lactation program in luminal cells, which was exacerbated upon loss of EpiDrivers. Remarkably, EpiDriver loss in basal cells also triggered an alveolar-like lineage conversion and accelerated formation of luminal-like tumors, suggesting a basal origin for luminal tumors. As EpiDrivers are mutated in 39% of human breast cancers, lineage infidelity and lactation mimicry may significantly contribute to early steps of breast cancer progression. Statement of significanceInfrequently mutated genes comprise most of the mutational burden in breast tumors but are poorly understood. In-vivo CRISPR screening identified functional tumor suppressors that converged on epigenetic regulation. Loss of epigenetic regulators accelerated tumorigenesis and revealed lineage infidelity and aberrant expression of lactation genes as potential early events in tumorigenesis.

cancer biology↗

Modeling High-grade serous ovarian carcinoma using a combination of in vivo electroporation and CRISPR/Cas9 mediated genome editing

Ovarian cancer remains the most lethal gynecological cancer today. High-grade serous ovarian carcinoma (HGSC) is the most common and lethal type of ovarian cancer and is most frequently diagnosed at advanced stages. Here, we developed a novel strategy to generate somatic ovarian cancer mouse models using a combination of in vivo electroporation and CRISPR/Cas9 mediated genome editing. We mutated tumor suppressor genes associated with HGSC in two different combinations; Brca1, Tp53, Pten with/without Lkb1 and successfully generated HGSC, however, with different latencies and pathophysiology. By utilizing Cre lineage tracing in our system, we visualized peritoneal micrometastases in an immune-competent environment. Because our strategy is flexible in selecting mutation combinations and targeting areas, it would be useful for generating ovarian cancer mouse models. Significance StatementHigh grade serous ovarian cancer (HGSC) is the most common ovarian malignancy but our knowledge of early tumorigenesis is still quite limited due to late diagnosis of patients. We developed a new strategy of generating mouse ovarian cancer models using a combination of in vivo electroporation and CRISPR-mediated genome editing. We demonstrated that a combination of three tumor suppressor gene mutations (Brca1, Tp53 and Pten) is sufficient to develop HGSCs. Interesting, an additional mutation in Lkb1 drastically changed tumor latency, penetrance and pathophysiology through changing its cell-of-origin. Our strategy is highly flexible in selection of mutation combinations and targeting areas in immune competent mice and useful to study early tumorigenesis of ovarian cancer.

cancer biology↗

Anatomical and cellular heterogeneity in the mouse oviduct-- its potential roles in reproduction and preimplantation development

The oviduct/fallopian tube is a tube-like structure that extends from the uterus to the ovary. It is an essential reproductive tissue that provides an environment for internal fertilization and preimplantation development. However, our knowledge of its regional and cellular heterogeneity is still limited. Here, we examined the anatomical complexity of mouse oviducts using modern imaging techniques and fluorescence reporter lines. We found that there are basic coiling patterns and turning points in the coiled mouse oviduct can serve as reliable landmarks for luminal morphological regionalities. We identified previously unrecognized anatomical structures in the isthmus and uterotubal junction (UTJ) that likely play important roles in reproduction. Interestingly, during ovulation, the isthmus was transiently plugged by a thick mucus, keeping the oocytes within the ampulla. Preimplantation embryos travelled along the oviduct and formed a queue within small compartments of the UTJ before uterine entry. Taken together, the oviduct luminal epithelium had highly diverse luminal structures with distinct cell populations reflecting its complex functions in reproduction.

physiology↗

Oviduct epithelial cells constitute two developmentally distinct lineages that are spatially separated along the distal-proximal axis

Owing to technical advances in single cell biology, the appreciation of cellular heterogeneity has increased, which has aided our understanding of organ function, homeostasis and disease progression. The oviduct (also known as the fallopian tube in humans) is the distal-most portion of the female reproductive tract. It is essential for reproduction and the proposed origin of high grade serous ovarian carcinoma (HGSOC). In mammals, the oviduct is morphologically segmented along the ovary-uterus axis into four evolutionally conserved regions. It is unknown however if there is a diversification of epithelial cell characteristics between these regions. In this study, we identified transcriptionally distinct populations of secretory and multiciliated cells restricted to the distal and proximal regions of the oviduct. We demonstrated that these distal and proximal populations are distinct lineages specified early in Mullerian duct development and are maintained separately. These results aid our understanding of epithelial development, homeostasis and initiation of disease from the oviduct.

developmental biology↗