Authors: Wu J, Kung J, Dong J, Chang L, Xie C, Habib A, Hawes S, Yang N, Chen V, Liu Z, Evans R, Liang B, Sun L, Ding J, Yu J, Saez-Atienzar S, Tang B, Khaliq Z, Lin DT, Le W, Cai H
Journal: Cell Rep. 2019 Jul 30;28(5):1167-1181.e7. doi: 10.1016/j.celrep.2019.06.095.
Parkinson's disease causes the most profound loss of the aldehyde dehydrogenase 1A1-positive (ALDH1A1+) nigrostriatal dopaminergic neuron (nDAN) subpopulation. The connectivity and functionality of ALDH1A1+ nDANs, however, remain poorly understood. Here, we show in rodent brains that ALDH1A1+ nDANs project predominantly to the rostral dorsal striatum, from which they also receive most monosynaptic inputs, indicating extensive reciprocal innervations with the striatal spiny projection neurons (SPNs). Functionally, genetic ablation of ALDH1A1+ nDANs causes severe impairments in motor skill learning, along with a reduction in high-speed walking. While dopamine replacement therapy accelerated walking speed, it failed to improve motor skill learning in ALDH1A1+ nDAN-ablated mice. Altogether, our study provides a comprehensive whole-brain connectivity map and reveals a key physiological function of ALDH1A1+ nDANs in motor skill acquisition, suggesting the motor learning processes require ALDH1A1+ nDANs to integrate diverse presynaptic inputs and supply dopamine with dynamic precision.
Authors: Ebrahim S, Chen D, Weiss M, Malec L, Ng Y, Rebustini I, Krystofiak E, Hu L, Liu J, Masedunskas A, Hardeman E, Gunning P, Kachar B, Weigert R
Journal: Nat Cell Biol. 2019 Jul 29. doi: 10.1038/s41556-019-0365-7.
Actomyosin networks, the cell's major force production machineries, remodel cellular membranes during myriad dynamic processes by assembling into various architectures with distinct force generation properties. While linear and branched actomyosin architectures are well characterized in cell-culture and cell-free systems, it is not known how actin and myosin networks form and function to remodel membranesin complex three-dimensional mammalian tissues. Here, we use four-dimensional spinning-disc confocal microscopy with image deconvolution to acquire macromolecular-scale detail of dynamic actomyosin networks in exocrine glands of live mice. We address how actin and myosin organize around large membrane-bound secretory vesicles and generate the forces required to complete exocytosis. We find that actin and non-muscle myosin II (NMII) assemble into previously undescribed polyhedral-like lattices around the vesicle membrane. The NMII lattice comprises bipolar minifilaments as well as non-canonical three-legged configurations. Using photobleaching and pharmacological perturbations in vivo, we show that actomyosin contractility and actin polymerization together push on the underlying vesicle membrane to overcome the energy barrier and complete exocytosis. Our imaging approach thus unveils a force-generating actomyosinlattice that regulates secretion in the exocrine organs of live animals.
Authors: Li L, Ameri AH, Wang S, Jansson KH, Casey OM, Yang Q, Beshiri ML, Fang L, Lake RG, Agarwal S, Alilin AN, Xu W, Yin J, Kelly K
Journal: Oncogene. 2019 Jul 16. doi: 10.1038/s41388-019-0873-8.
Early growth response-1 (EGR1) is a transcription factor correlated with prostate cancer (PC) progression in a variety of contexts. For example, EGR1 levels increase in response to suppressed androgen receptor signaling or loss of the tumor suppressor, PTEN. EGR1 has been shown to regulate genes influencing proliferation, apoptosis, immune cell activation, and matrix degradation, among others. Despite this, the impact of EGR1 on PC metastatic colonization is unclear. We demonstrate using a PC model (DU145/RasB1) of bone and brain metastasis that EGR1 expression regulates angiogenic and osteoclastogenic properties of metastases. We have shown previously that FN14 (TNFRSF12A) and downstream NF-κB signaling is required for metastasis in this model. Here we demonstrate that FN14 ligation also leads to NF-κB-independent, MEK-dependent EGR1 expression. EGR1-depletion in DU145/RasB1 cells reduced both the number and size of metastases but did not affect primary tumor growth. Decreased EGR1 expression led to reduced blood vessel density in brain and bone metastases as well as decreased osteolytic bone lesion area and reduced numbers of osteoclasts at the bone-tumor interface. TWEAK (TNFSF12) induced several EGR1-dependent angiogenic and osteoclastogenic factors (e.g., PDGFA, TGFB1, SPP1, IL6, IL8, and TGFA, among others). Consistent with this, in clinical samples of PC, the level of several genes encoding angiogenic/osteoclastogenic pathway effectors correlated with EGR1 levels. Thus, we show here that EGR1 has a direct effect on prostate cancer metastases. EGR1 regulates angiogenic and osteoclastogenic factors, informing the underlying signaling networks that impact autonomous and microenvironmental mechanisms of cancer metastases.
Authors: Morgan CJ, Hedman AC, Li Z, Sacks DB
Journal: Sci Rep. 2019 Jul 30;9(1):11057. doi: 10.1038/s41598-019-46677-9.
The Ras family of small GTPases modulates numerous essential processes. Activating Ras mutations result in hyper-activation of selected signaling cascades, which leads to human diseases. The high frequency of Ras mutations in human malignant neoplasms has led to Ras being a desirable chemotherapeutic target. The IQGAP family of scaffold proteins binds to and regulates multiple signaling molecules, including the Rho family GTPases Rac1 and Cdc42. There are conflicting data in the published literature regarding interactions between IQGAP and Ras proteins. Initial reports showed no binding, but subsequent studies claim associations of IQGAP1 and IQGAP3 with K-Ras and H-Ras, respectively. Therefore, we set out to resolve this controversy. Here we demonstrate that neither endogenous IQGAP1 nor endogenous IQGAP3 binds to the major Ras isoforms, namely H-, K-, and N-Ras. Importantly, Ras activation by epidermal growth factor is not altered when IQGAP1 or IQGAP3 proteins are depleted from cells. These data strongly suggest that IQGAP proteins are not functional interactors of H-, K-, or N-Ras and challenge the rationale for targeting the interaction of Ras with IQGAP for the development of therapeutic agents.
Authors: Staunton JR, So WY, Paul CD, Tanner K
Journal: Proc Natl Acad Sci U S A. 2019 Jul 2. pii: 201814271. doi: 10.1073/pnas.1814271116. [Epub ahead of print]
Mechanical homeostasis describes how cells sense physical cues from the microenvironment and concomitantly remodel both the cytoskeleton and the surrounding extracellular matrix (ECM). Such feedback is thought to be essential to healthy development and maintenance of tissue. However, the nature of the dynamic coupling between microscale cell and ECM mechanics remains poorly understood. Here we investigate how and whether cells remodel their cortex and basement membrane to adapt to their microenvironment. We measured both intracellular and extracellular viscoelasticity, generating a full factorial dataset on five cell lines in two ECMs subjected to four cytoskeletal drug treatments at two time points. Nonmalignant breast epithelial cells show a similar viscoelasticity to that measured for the local ECM when cultured in 3D laminin-rich ECM. In contrast, the malignant counterpart is stiffer than the local environment. We confirmed that other mammary cancer cells embedded in tissue-mimetic hydrogels are nearly four-fold stiffer than the surrounding ECM. Perturbation of actomyosin did not yield uniform responses but instead depended on the cell type and chemistry of the hydrogel. The observed viscoelasticity of both ECM and cells were well described by power laws in a frequency range that governs single filament cytoskeletal dynamics. Remarkably, the intracellular and extracellular power law parameters for the entire dataset collectively fall onto two parallel master curves described by just two parameters. Our work shows that tumor cells are mechanically plastic to adapt to many environments and reveals dynamical scaling behavior in the microscale mechanical responses of both cells and ECM.
Authors: Solinski HJ, Dranchak P, Oliphant E, Gu X, Earnest TW, Braisted J, Inglese J, Hoon MA
Journal: Sci Transl Med. 2019 Jul 10;11(500). pii: eaav5464. doi: 10.1126/scitranslmed.aav5464.
There is a major clinical need for new therapies for the treatment of chronic itch. Many of the molecular components involved in itch neurotransmission are known, including the neuropeptide NPPB, a transmitter required for normal itch responses to multiple pruritogens in mice. Here, we investigated the potential for a novel strategy for the treatment of itch that involves the inhibition of the NPPB receptor NPR1 (natriuretic peptide receptor 1). Because there are no available effective human NPR1 (hNPR1) antagonists, we performed a high-throughput cell-based screen and identified 15 small-molecule hNPR1 inhibitors. Using in vitro assays, we demonstrated that these compounds specifically inhibit hNPR1 and murine NPR1 (mNPR1). In vivo, NPR1 antagonism attenuated behavioral responses to both acute itch- and chronic itch-challenged mice. Together, our results suggest that inhibiting NPR1 might be an effective strategy for treating acute and chronic itch.
Authors: Shrestha D, Rahman ML, Hinkle SN, Workalemahu T, Tekola-Ayele F
Journal: Obesity (Silver Spring). 2019 Jul;27(7):1150-1160. doi: 10.1002/oby.22499.
OBJECTIVE: Associations between maternal genetic risk for obesity and fetal weight were examined at the end of the first (13 weeks 6 days), second (27 weeks 6 days), and third (40 weeks 0 days) trimesters of pregnancy among four race/ethnic groups in the US.
METHODS: For 603 white, 591 black, 535 Hispanic, and 216 Asian women, maternal genetic risk score (GRS) was calculated as the sum of 189 BMI-increasing alleles and was categorized into high or low GRS. Associations between GRS (continuous and categorical) and estimated fetal weight were tested overall and stratified by prepregnancy BMI, gestational weight gain (GWG), and fetal sex.
RESULTS: High GRS compared with low GRS was associated with increased fetal weight at the end of the second (β: 22.7 g; 95% CI: 2.4-43.1; P = 0.03) and third trimesters (β: 88.3 g; 95% CI: 9.0-167.6; P = 0.03) among Hispanic women. The effect of GRS was stronger among Hispanic women with normal prepregnancy weight, adequate first trimester GWG, or inadequate second trimester GWG (P < 0.05). Among Asian women, high GRS was associated with increased weight among male fetuses but decreased weight among female fetuses (P < 0.05).
CONCLUSIONS: Maternal obesity genetic risk was associated with fetal weight with potential effect modifications by maternal prepregnancy BMI, GWG, and fetal sex.
Authors: Nair NU, Das A, Rogkoti VM, Fokkelman M, Marcotte R, de Jong CG, Koedoot E, Lee JS, Meilijson I, Hannenhalli S, Neel BG, de Water BV, Le Dévédec SE, Ruppin E
Journal: Sci Rep. 2019 Jul 29;9(1):10989. doi: 10.1038/s41598-019-47440-w.
The efficacy of prospective cancer treatments is routinely estimated by in vitro cell-line proliferation screens. However, it is unclear whether tumor aggressiveness and patient survival are influenced more by the proliferative or the migratory properties of cancer cells. To address this question, we experimentally measured proliferation and migration phenotypes across more than 40 breast cancer cell-lines. Based on the latter, we built and validated individual predictors of breast cancer proliferation and migration levels from the cells' transcriptomics. We then apply these predictors to estimate the proliferation and migration levels of more than 1000 TCGA breast cancer tumors. Reassuringly, both estimates increase with tumor's aggressiveness, as qualified by its stage, grade, and subtype. However, predicted tumor migration levels are significantly more strongly associated with patient survival than the proliferation levels. We confirmed these findings by conducting siRNA knock-down experiments on the highly migratory MDA-MB-231 cell lines and deriving gene knock-down based proliferation and migration signatures. We show that cytoskeletal drugs might be more beneficial in patients with high predicted migration levels. Taken together, these results testify to the importance of migration levels in determining patient survival.
Authors: Farfel-Becker T, Roney JC, Cheng XT, Li S,Cuddy SR, Sheng ZH
Journal: Cell Rep. 2019 Jul 2;28(1):51-64.e4. doi: 10.1016/j.celrep.2019.06.013.
Neurons face the challenge of maintaining cellular homeostasis through lysosomal degradation. While enzymatically active degradative lysosomes are enriched in the soma, their axonal trafficking and positioning and impact on axonal physiology remain elusive. Here, we characterized axon-targeted delivery of degradative lysosomes by applying fluorescent probes that selectively label active forms of lysosomal cathepsins D, B, L, and GCase. By time-lapse imaging of cortical neurons in microfluidic devices and standard dishes, we reveal that soma-derived degradative lysosomes rapidly influx into distal axons and target to autophagosomes and Parkinson disease-related α-synuclein cargos for local degradation. Impairing lysosome axonal delivery induces an aberrant accumulation of autophagosomes and α-synuclein cargos in distal axons. Our study demonstrates that the axon is an active compartment for local degradation and reveals fundamental aspects of axonal lysosomal delivery and maintenance. Our work establishes a foundation for investigations into axonal lysosome trafficking and functionality in neurodegenerative diseases.
Authors: Nagashima H, Mahlakõiv T, Shih HY, Davis FP, Meylan F, Huang Y, Harrison OJ, Yao C, Mikami Y, Urban JF Jr, Caron KM, Belkaid Y, Kanno Y, Artis D, O'Shea JJ
Journal: Immunity. 2019 Jul 16. pii: S1074-7613(19)30279-1. doi: 10.1016/j.immuni.2019.06.009. [Epub ahead of print]
Innate lymphocytes maintain tissue homeostasis at mucosal barriers, with group 2 innate lymphoid cells (ILC2s) producing type 2 cytokines and controlling helminth infection. While the molecular understanding of ILC2 responses has advanced, the complexity of microenvironmental factors impacting ILC2s is becoming increasingly apparent. Herein, we used single-cell analysis to explore the diversity of gene expression among lung lymphocytes during helminth infection. Following infection, we identified a subset of ILC2s that preferentially expressed Il5-encoding interleukin (IL)-5, together with Calca-encoding calcitonin gene-related peptide (CGRP) and its cognate receptor components. CGRP in concert with IL-33 and neuromedin U (NMU) supported IL-5 but constrained IL-13 expression and ILC2 proliferation. Without CGRP signaling, ILC2 responses and worm expulsion were enhanced. Collectively, these data point to CGRP as a context-dependent negative regulatory factor that shapes innate lymphocyte responses to alarmins and neuropeptides during type 2 innate immune responses.