Insulin resistance is present in one-quarter of the general population, predisposing to a wide-range of diseases. Our aim was to identify cell-intrinsic determinants of insulin resistance in this population using IPS cell-derived myoblasts (iMyos). We found that these cells exhibited a large network of altered protein phosphorylation in vitro. Integrating these data with data from type-2-diabetic iMyos revealed critical sites of conserved altered phosphorylation in IRS-1, AKT, mTOR and TBC1D1, in addition to changes in protein phosphorylation involved in Rho/Rac signaling, chromatin organization and RNA processing. There were also striking differences in the phosphoproteome in cells from males versus females. These sex-specific and insulin resistance defects were linked to functional differences in downstream actions. Thus, there are cell-autonomous signaling alterations associated with insulin resistance within the general population and important differences in males and females, many of which are shared with diabetes, and contribute to differences in physiology and disease.
Nida Haider, Jasmin Lebastchi, Ashok Kumar Jayavelu, Thiago M. Batista, Hui Pan, Jonathan M. Dreyfuss, Ivan Carcamo-Orive, Joshua W. Knowles, Matthias Mann, C. Ronald Kahn
The heterogeneity of human hematopoietic stem (HSCs) and progenitor cells (HPCs) under stress conditions such as ex vivo expansion is poorly understood. Here we report that the frequencies of SCID repopulating cells (SRCs) were greatly decreased in cord blood（CB）CD34+ HSCs and HPCs upon ex vivo culture. Transcriptome analysis and metabolic profiling demonstrated that mitochondrial oxidative stress of human CB HSCs and HPCs notably increased along with loss of stemness. Limiting dilution analysis (LDA) revealed that functional human HSCs were enriched in cell populations with low levels of mitochondrial reactive oxygen species (mitoROS) during ex vivo culture. Using single cell RNA sequencing (scRNA-seq) analysis of mitoROS low cell population, we demonstrated that functional HSCs were substantially enriched in the Adhesion G protein-coupled receptor G1 positive (ADGRG1+) population of CD34+CD133+ CB cells upon ex vivo expansion stress. GSEA analysis revealed that HSC signature genes including MSI2 and MLLT3 are enriched in CD34+CD133+ ADGRG1+ CB HSCs. Our study reveals that ADGRG1 enriches for functional human HSCs under oxidative stress during ex vivo culture, which can be a reliable target for drug screening of agonists of HSC expansion.
Yandan Chen, Shuyi Fang, Qingwei Ding, Rongzhen Jiang, Jiefeng He, Qin Wang, Yuting Jin, Xinxin Huang, Sheng Liu, Maegan Capitano, Thao Trinh, Yincheng Teng, Qingyou Meng, Jun Wan, Hal Broxmeyer, Bin Guo
Glioblastoma (GBM) remains among the deadliest of human malignancies, and the emergence of the cancer stem cell (CSC) phenotype represents a major challenge to durable treatment response. Because the environmental and lifestyle factors that impact CSC populations are not clear, we sought to understand the consequences of diet on CSC enrichment. We evaluated disease progression in mice fed an obesity-inducing high-fat diet (HFD) versus a low-fat, control diet. HFD resulted in hyper-aggressive disease accompanied by CSC enrichment and shortened survival. HFD drove intracerebral accumulation of saturated fats, which inhibited the production of the cysteine metabolite and gasotransmitter, hydrogen sulfide (H2S). H2S functions principally through protein S-sulfhydration and regulates multiple programs including bioenergetics and metabolism. Inhibition of H2S increased proliferation and chemotherapy resistance, whereas treatment with H2S donors led to death of cultured GBM cells and stasis of GBM tumors in vivo. Syngeneic GBM models and GBM patient specimens present an overall reduction in protein S-sulfhydration, primarily associated with proteins regulating cellular metabolism. These findings provide clear evidence that diet modifiable H2S signaling serves to suppress GBM by restricting metabolic fitness, while its loss triggers CSC enrichment and disease acceleration. Interventions augmenting H2S bioavailability concurrent with GBM standard of care may improve outcomes for GBM patients.
Daniel J. Silver, Gustavo A. Roversi, Nazmin Bithi, Sabrina Z. Wang, Katie M. Troike, Chase K.A. Neumann, Grace K. Ahuja, Ofer Reizes, J. Mark Brown, Christopher Hine, Justin D. Lathia
Down syndrome (DS), caused by trisomy of chromosome 21, occurs in 1 of every 800 live births. Early defects in cortical development likely account for the cognitive impairments in DS, although the underlying molecular mechanism remains elusive. Here, we performed histological assays and unbiased single-cell RNA sequencing (scRNA-seq) analysis on cerebral organoids derived from four euploid cell lines and from induced pluripotent stem cells (iPSCs) from three individuals with trisomy 21 to explore cell type-specific abnormalities associated with DS during early brain development. We found that neurogenesis was significantly affected based on diminished proliferation and decreased expression of layer II and IV markers in cortical neurons in the subcortical regions; this may be responsible for the reduced size of the organoids. Furthermore, suppression of the DSCAM-PAK1 pathway which showed enhanced activities in DS) via CRISPR/Cas9, CRISPRi or small-molecule inhibitor treatment reverses abnormal neurogenesis, thereby increasing the size of organoids derived from DS iPSCs. Our study demonstrated that 3D cortical organoids developed in vitro are a valuable model of DS and provided a direct link between dysregulation of the DSCAM-PAK1 pathway and developmental brain defects in DS.
Xiao-Yan Tang, Lei Xu, Jingshen Wang, Yuan Hong, Yuanyuan Wang, Qian Zhu, Da Wang, Xin-Yue Zhang, Chun-Yue Liu, Kai-Heng Fang, Xiao Han, Shihua Wang, Xin Wang, Min Xu, Anita Bhattacharyya, Xing Guo, Mingyan Lin, Yan Liu
Myelofibrosis (MF) are a non-BCR-ABL myeloproliferative neoplasms (NMPs) associated with poor outcomes. Current treatment has little effect on the natural history of the disease. MF results from complex interactions between 1) the malignant clone, 2) an inflammatory context, and 3) remodeling of the bone marrow (BM) microenvironment. Each of these points is a potential target of PPAR-y activation. Here, we demonstrated the therapeutic potential of PPAR-y agonists in resolving MF in three mouse models. We showed that PPAR-y agonists reduce myeloproliferation, modulate inflammation, and protect the BM stroma in vitro and ex vivo. Activation of PPAR-y constitutes a relevant therapeutic target in MF and our data support the possibility of using PPAR-y agonists in clinical practice.
Juliette Lambert, Joseph Saliba, Carolina Calderon, Karine Sii-Felice, Mohammad Salma, Valérie Edmond, Jean-Claude Alvarez, Marc Delord, Caroline Marty, Isabelle Plo, Jean-Jacques Kiladjian, Eric Soler, William Vainchenker, Jean-Luc Villeval, Philippe Rousselot, Stephane Prost
Bardet-Biedl Syndrome (BBS) is a rare autosomal recessive disorder caused by mutations in genes encoding components of the primary cilium and characterized by hyperphagic obesity. To investigate the molecular basis of obesity in human BBS, we developed a cellular model of BBS using induced pluripotent stem cell (iPSCs)-derived hypothalamic arcuate-like neurons. BBS mutations BBS1M390R and BBS10C91fsX95 did not affect neuron differentiation efficiency but caused morphological defects including impaired neurite outgrowth and longer primary cilia. Single-cell RNA sequencing of BBS1M390R hypothalamic neurons identified several downregulated pathways including insulin and cAMP signaling, and axon guidance. Additional studies demonstrated that BBS1M390R and BBS10C91fsX95 mutations impaired insulin signaling in both human fibroblasts and iPSC-derived neurons. Overexpression of intact BBS10 fully restored insulin signaling by restoring insulin receptor tyrosine phosphorylation in BBS10C91fsX95 neurons. Moreover, mutations in BBS1 and BBS10 impaired leptin-mediated p-STAT3 activation in iPSC-derived hypothalamic neurons. Correction of the BBS mutation by CRISPR rescued leptin signaling. POMC expression and neuropeptide production were decreased in BBS1M390R and BBS10C91fsX95 iPSC-derived hypothalamic neurons. In the aggregate, these data provide insights into the anatomic and functional mechanisms by which components of the BBSome in CNS primary cilia mediate effects on energy homeostasis.
Liheng Wang, Yang Liu, George Stratigopoulos, Sunil K. Panigrahi, Lina Sui, Charles A. LeDuc, Hannah J. Glover, Maria Caterina De Rosa, Lisa C. Burnett, Damian J. Williams, Linshan Shang, Robin Goland, Stephen H. Tsang, Sharon L. Wardlaw, Dieter Egli, Deyou Zheng, Claudia A. Doege, Rudolph L. Leibel
In order to sustain proficient life-long hematopoiesis, hematopoietic stem cells (HSCs) must possess robust mechanisms to preserve their quiescence and genome integrity. DNA-damaging stress can perturb HSC homeostasis by affecting their survival, self-renewal and differentiation. Ablation of the kinase ATM, a master regulator of the DNA damage response, impairs HSC fitness. Paradoxically, we show here that loss of a single allele of Atm enhances HSC functionality in mice. To explain this observation, we explored a possible link between ATM and the tumor suppressor PTEN, which also regulates HSC function. We generated and analyzed a knock-in mouse line (PtenS398A/S398A), in which PTEN cannot be phosphorylated by ATM. Similar to Atm+/-, PtenS398A/S398A HSCs have enhanced hematopoietic reconstitution ability, accompanied by resistance to apoptosis induced by genotoxic stress. Single-cell transcriptomic analyses and functional assays revealed that dormant PtenS398A/S398A HSCs aberrantly tolerate elevated mitochondrial activity and the accumulation of reactive oxygen species, which are normally associated with HSC priming for self-renewal or differentiation. Our results unveil a molecular connection between ATM and PTEN, which couples the response to genotoxic stress and dormancy in HSC.
Jerome Fortin, Christian Bassi, Parameswaran Ramachandran, Wanda Y. Li, Ruxiao Tian, Ida Zarrabi, Graham Hill, Bryan E. Snow, Jillian Haight, Chantal Tobin, Kelsey Hodgson, Andrew Wakeham, Vuk Stambolic, Tak W. Mak
How particular bone marrow niche factors contribute to the leukemogenic activities of leukemia-initiating cells (LICs) remain largely unknown. Here, we showed that ATP levels were markedly increased in the bone marrow niches of mice with acute myeloid leukemia (AML), and LICs preferred to localizing to the endosteal niche with relatively high ATP levels, as indicated by a sensitive ATP indicator. ATP could efficiently induce the influx of ions into LICs in an MLL-AF9-induced murine AML model via the ligand-gated ion channel P2X7. P2x7 deletion led to notably impaired homing and self-renewal capacities of LICs and contributed to an ~5-fold decrease in the number of functional LICs but had no effect on normal hematopoiesis. ATP-P2X7 signaling enhanced the calcium flux-mediated phosphorylation of CREB, which further transactivated the Phgdh expression to maintain serine metabolism and LIC fates. P2X7-knockdown resulted in a markedly extended survival of recipients transplanted with either human AML cell lines or primary leukemia cells. Blockade of ATP-P2X7 signaling could efficiently inhibit leukemogenesis. Here, we provide a unique perspective for understanding how ATP-P2X7 signaling sustains the LIC activities, which may benefit the development of specific strategies for targeting LICs or other types of cancer stem cells
Xiaoxiao He, Jiangbo Wang, Xiaona Yang, Xiuze Zhang, Dan Huang, Xie Li, Yejun Zou, Chiqi Chen, Zhuo Yu, Li Xie, Yaping Zhang, Ligen Liu, Shangang Li, Yuzheng Zhao, Hongfang Shao, Ye Yu, Junke Zheng
Small extracellular vesicles (SEVs) are functional messengers of certain cellular niches to permit non-contact cell communications. Whether niche-specific SEVs fulfill this role in cancer is unclear. Here, we used seven cell-type specific mouse Cre lines to conditionally knockout Vps33b in Cdh5+ or Tie2+ endothelial cells (ECs), Lepr+ bone marrow perivascular cells, Osx+ osteo-progenitor cells (OPCs), Pf4+ megakaryocytes and Tcf21+ spleen stromal cells. We then examined the effects of reduced SEV secretion on progression of MLL-AF9 induced acute myeloid leukemia (AML) as well as normal hematopoiesis. Blocking SEV secretion from ECs, but not perivascular cells, megakaryocytes or spleen stromal cells, markedly delayed the leukemia progression. Notably, reducing SEV production from ECs had no effect on normal hematopoiesis. Protein analysis showed that EC-derived SEVs contained a high level of ANGPTL2, which accelerated leukemia progression via binding to LILRB2 receptor. Moreover, ANGPTL2-SEVs released from ECs were governed by VPS33B. Importantly, ANGPTL2-SEVs were also required for primary human AML cell maintenance. These findings demonstrate a role of niche-specific SEVs in cancer development and suggest that targeting ANGPTL2-SEVs from ECs might be a potential strategy to interfere certain types of AML.
Dan Huang, Guohuan Sun, Xiaoxin Hao, Xiaoxiao He, Zhaofeng Zheng, Chiqi Chen, Zhuo Yu, Li Xie, Shihui Ma, Ligen Liu, Bo O. Zhou, Hui Cheng, Junke Zheng, Tao Cheng
Zeb1, a zinc finger E-box binding homeobox epithelial-mesenchymal (EMT) transcription factor, confers properties of ‘stemness’, such as self-renewal, in cancer. Yet little is known about the function of Zeb1 in adult stem cells. Here, we used the hematopoietic system, as a well-established paradigm of stem cell biology, to evaluate Zeb1 mediated regulation of adult stem cells. We employed a conditional genetic approach using the Mx1-Cre system to specifically knockout (KO) Zeb1 in adult hematopoietic stem cells (HSCs) and their downstream progeny. Acute genetic deletion of Zeb1 led to rapid onset thymic atrophy and apoptosis driven loss of thymocytes and T cells. A profound cell-autonomous self-renewal defect and multi-lineage differentiation block was observed in Zeb1 KO HSCs. Loss of Zeb1 in HSCs activated transcriptional programs of deregulated HSC maintenance and multi-lineage differentiation genes, and of cell polarity, consisting of cytoskeleton, lipid metabolism/lipid membrane and cell adhesion related genes. Notably, Epithelial cell adhesion molecule (EpCAM) expression was prodigiously upregulated in Zeb1 KO HSCs, which correlated with enhanced cell survival, diminished mitochondrial metabolism, ribosome biogenesis, and differentiation capacity and an activated transcriptomic signature associated with acute myeloid leukemia (AML) signaling. ZEB1 expression was downregulated in AML patients and Zeb1 KO in the malignant counterparts of HSCs - leukemic stem cells (LSCs) - accelerated MLL-AF9 and Meis1a/Hoxa9-driven AML progression, implicating Zeb1 as a tumor suppressor in AML LSCs. Thus, Zeb1 acts as a transcriptional regulator in hematopoiesis, critically co-ordinating HSC self-renewal, apoptotic and multi-lineage differentiation fates required to suppress leukemic potential in AML.
Alhomidi Almotiri, Hamed Ahmad A. Alzahrani, Juan Bautista Menendez-Gonzalez, Ali Abdelfattah, Badi Alotaibi, Lubaid Saleh, Adelle Greene, Mia R. F. Georgiou, Alex Gibbs, Amani Salem Alsayari, Sarab Taha, Leigh-Anne Thomas, Dhruv Shah, Sarah Edkins, Peter J. Giles, Marc P. Stemmler, Simone Brabletz, Thomas Brabletz, Ashleigh S. Boyd, Florian A. Siebzehnrubl, Neil P. Rodrigues