Publications by authors named "Matthew C Havrda"

20 Publications

  • Page 1 of 1

Lifestyle Factors and Parkinson's Disease Risk in a Rural New England Case-Control Study.

Parkinsons Dis 2021 2;2021:5541760. Epub 2021 Jul 2.

Geisel School of Medicine at Dartmouth, Rubin Building, Lebanon, NH, USA.

Introduction: Parkinson's disease (PD) is an age-related neurodegenerative disease likely caused by complex interactions between genetic and environmental risk factors. Exposure to pesticides, toxic metals, solvents, and history of traumatic brain injury have been implicated as environmental risk factors for PD, underscoring the importance of identifying risk factors associated with PD across different communities.

Methods: We conducted a questionnaire-based case-control study in a rural area on the New Hampshire/Vermont border, enrolling PD patients and age- and sex-matched controls from the general population between 2017 and 2020. We assessed frequent participation in a variety of recreational and occupational activities and surveyed potential chemical exposures.

Results: Suffering from "head trauma or a concussion" prior to diagnosis was associated with a fourfold increased risk of PD. Adjustment for head trauma negated any risk of participation in "strenuous athletic activities." We observed a 2.7-fold increased risk of PD associated with activities involving lead (adjusted =0.038).

Conclusion: Implicating these factors in PD risk favors public health efforts in exposure mitigation while also motivating future work mechanisms and intervention opportunities.
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http://dx.doi.org/10.1155/2021/5541760DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8270694PMC
July 2021

Bbc3 loss enhances survival and protein clearance in neurons exposed to the organophosphate pesticide chlorpyrifos.

Toxicol Sci 2021 Jul 21. Epub 2021 Jul 21.

Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH.

Exposure to environmental toxicants can increase the risk of developing age-related neurodegenerative disorders. Exposure to the widely used organophosphate pesticide chlorpyrifos (CPF) is associated with increased risk of developing Alzheimer's disease (AD) and Parkinson's disease (PD), but the cellular mechanisms underlying CPF toxicity in neurons are not completely understood. We evaluated CPF toxicity in mouse primary cortical neuronal cultures, using RNA-Seq to identify cellular pathways modulated by CPF. CPF exposure altered the expression of genes associated with intrinsic apoptosis, significantly elevating expression of the pro-apoptotic mediator Bbc3/Puma. Bbc3 loss attenuated CPF driven neurotoxicity, induction of other intrinsic apoptosis regulatory genes including Trp53 and Pmaip1 (encoding the NOXA protein), and cleavage of apoptosis executors caspase 3 and PARP. CPF exposure was associated with enhanced expression of ER stress-related genes and proteins and the accumulation of high molecular weight protein species in primary neuronal cultures. No evidence of alterations in the ubiquitin-proteosome system were observed, however, autophagy-related proteins were upregulated in CPF-treated Bbc3-/- neuronal cultures compared with identically exposed WT cultures. Elevated autophagy-related protein expression in Bbc3-/- neuronal cultures was associated with a reduction in CPF-induced high molecular weight alpha-synuclein and tau immunoreactive protein aggregates. Studies indicate that Bbc3-/- neuronal cultures enhance the ER stress response and upregulate protein clearance mechanisms as a component of resistance to CPF-mediated toxicity.
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http://dx.doi.org/10.1093/toxsci/kfab090DOI Listing
July 2021

The helix-loop-helix transcriptional regulator Id4 is required for terminal differentiation of luminal epithelial cells in the prostate.

Oncoscience 2021 24;8:14-30. Epub 2021 Mar 24.

Center for Cancer Research and Therapeutics Development, Clark Atlanta University, Atlanta GA, USA.

Inhibitor of differentiation 4 (Id4), a member of the helix-loop-helix family of transcriptional regulators has emerged as a tumor suppressor in prostate cancer. In this study we investigated the effect of loss of Id4 () on mouse prostate development. Histological analysis was performed on prostates from 25 days, 3 months and 6 months old mice. Expression of Amacr, Ck8, Ck18, Fkbp51, Fkbp52, androgen receptor, Pten, sca-1 and Nkx3.1 was investigated by immunohistochemistry. Results were compared to the prostates from mice. mice had smaller prostates with fewer and smaller tubules. Subtle PIN like lesions were observed at 6mo. Decreased Nkx3.1 and Pten and increased stem cell marker sca-1, PIN marker Amacr and basal cell marker p63 was observed at all ages. Persistent Ck8 and Ck18 expression suggested that loss of Id4 results in epithelial commitment but not terminal differentiation in spite of active Ar. Loss of Id4 attenuates normal prostate development and promotes hyperplasia/ dysplasia with PIN like lesions. The results suggest that loss of Id4 maintains stem cell phenotype of "luminal committed basal cells", identifying a unique prostate developmental pathway regulated by Id4.
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http://dx.doi.org/10.18632/oncoscience.524DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8045964PMC
March 2021

Plasma-borne indicators of inflammasome activity in Parkinson's disease patients.

NPJ Parkinsons Dis 2021 Jan 4;7(1). Epub 2021 Jan 4.

Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth College, Hanover, NH, USA.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor and non-motor symptoms and loss of dopaminergic neurons of the substantia nigra. Inflammation and cell death are recognized aspects of PD suggesting that strategies to monitor and modify these processes may improve the management of the disease. Inflammasomes are pro-inflammatory intracellular pattern recognition complexes that couple these processes. The NLRP3 inflammasome responds to sterile triggers to initiate pro-inflammatory processes characterized by maturation of inflammatory cytokines, cytoplasmic membrane pore formation, vesicular shedding, and if unresolved, pyroptotic cell death. Histologic analysis of tissues from PD patients and individuals with nigral cell loss but no diagnosis of PD identified elevated expression of inflammasome-related proteins and activation-related "speck" formation in degenerating mesencephalic tissues compared with controls. Based on previous reports of circulating inflammasome proteins in patients suffering from heritable syndromes caused by hyper-activation of the NLRP3 inflammasome, we evaluated PD patient plasma for evidence of inflammasome activity. Multiple circulating inflammasome proteins were detected almost exclusively in extracellular vesicles indicative of ongoing inflammasome activation and pyroptosis. Analysis of plasma obtained from a multi-center cohort identified elevated plasma-borne NLRP3 associated with PD status. Our findings are consistent with others indicating inflammasome activity in neurodegenerative disorders. Findings suggest mesencephalic inflammasome protein expression as a histopathologic marker of early-stage nigral degeneration and suggest plasma-borne inflammasome-related proteins as a potentially useful class of biomarkers for patient stratification and the detection and monitoring of inflammation in PD.
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http://dx.doi.org/10.1038/s41531-020-00147-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7782812PMC
January 2021

The effect of botulinum toxin on ureteral inflammation.

World J Urol 2021 Jun 21;39(6):2197-2204. Epub 2020 Jul 21.

Department of Urology, Dartmouth-Hitchcock, 1 Medical Center Dr, Lebanon, NH, USA.

Purpose: The impact of onabotulinum toxin type A (BoNT-A) on bladder afferent nerve pathways and chemosensory functions is an active area of investigation. There may be a role for BoNT-A in disorders of the ureter; however, no histologic studies have assessed the effects of BoNT-A on ureteral tissue. Our objective was to develop an animal model of ureteral inflammation and determine the impact of ureteral BoNT-A instillation on known mechanisms of inflammation.

Methods: The safety and feasibility of a novel animal model of ureteral inflammation was assessed. Through open cystotomy, the effect of ureteral BoNT-A instillation on inflammation was determined through H&E, masson's trichrome, Ki-67 stain, and prostaglandin E (PGE) synthase expression, a known marker of pain and inflammation in ureteral tissue. Urothelial microstructure was assessed using electron microscopy and standard histologic techniques.

Results: All experiments were carried to completion, and no systemic signs of botulinum toxicity were seen. BoNT-A exposure was associated with a decrease in PGE synthase expression in a dose-dependent fashion. BoNT-A exposure was not found to impact collagen deposition or cell proliferation. Disruption of tight junctions between urothelial cells was observed under conditions of inflammation.

Conclusion: We describe the feasibility of a novel in vivo model of ureteral inflammation and report the first histologic study of the effects of BoNT-A on the ureter. Preliminary findings show that BoNT-A attenuates ureteral PGE synthase expression under conditions of inflammation. The application of BoNT-A may provide anti-inflammatory and analgesic effects in the context of ureteral disorders.
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http://dx.doi.org/10.1007/s00345-020-03365-yDOI Listing
June 2021

Slc6a3-dependent expression of a CAPS-associated Nlrp3 allele results in progressive behavioral abnormalities and neuroinflammation in aging mice.

J Neuroinflammation 2020 Jul 17;17(1):213. Epub 2020 Jul 17.

Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth College, 1 Rope Ferry Road, Hanover, NH, 03755, USA.

Background: An association between neuroinflammation and age-related neurologic disorders has been established but the molecular mechanisms and cell types involved have not been thoroughly characterized. Activity of the proinflammatory NLRP3 inflammasome is implicated in Alzheimer's and Parkinson's disease and our recent studies in patients suggest that dopaminergic neurons within the degenerating mesencephalon express NLRP3 throughout the progression of PD. Here, we directly test the impact of enhanced inflammasome activity in mesencephalic neurons by characterizing motor function, tissue integrity, and neuroinflammation in aging mice harboring hyperactivating mutations within the endogenous murine Nlrp3 locus, enabled only in cells expressing the dopaminergic neuron-specific Slc6a3 promoter.

Methods: We compared mice harboring inducible alleles encoding the cryopyrin-associated periodic syndrome activating mutations Nlrp3 and Nlrp3 inserted into the endogenous mouse Nlrp3 locus. Tissue specific expression was driven by breeding these animals with mice expressing Cre recombinase under the control of the dopaminergic neuron-specific Slc6a3 promoter. The experimental mice, designed to express hyperactive NLRP3 only when the endogenous mouse Nlrp3 promotor is active in dopaminergic neurons, were analyzed throughout 18 months of aging using longitudinal motor function assessments. Biochemical and histologic analyses of mesencephalic tissues were conducted in 1- and 18-month-old animals.

Results: We observed progressive and significant deficits in motor function in animals expressing Nlrp3, compared with animals expressing Nlrp3 and Nlrp3. Age-dependent neuroinflammatory changes in the mesencephalon were noted in all animals. Analysis of GFAP-immunoreactive astrocytes in the substantia nigra revealed a significant increase in astrocyte number in animals expressing Nlrp3 compared with Nlrp3 and Nlrp3. Further analysis of Nlrp3 striatal tissues indicated genotype specific gliosis, elevated Il1b expression, and both morphologic and gene expression indicators of proinflammatory A1 astrocytes.

Conclusions: Dopaminergic neurons have the potential to accumulate NLRP3 inflammasome activators with age, including reactive oxygen species, dopamine metabolites, and misfolded proteins. Results indicate the Nlrp3 locus is active in dopaminergic neurons in aging mice, and that the hyperactive Nlrp3 allele can drive neuroinflammatory changes in association with progressive behavioral deficits. Findings suggest neuronal NLRP3 inflammasome activity may contribute to neuroinflammation observed during normal aging and the progression of neurologic disorders.
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http://dx.doi.org/10.1186/s12974-020-01866-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7368774PMC
July 2020

Characterizing the heterogeneity in 5-aminolevulinic acid-induced fluorescence in glioblastoma.

J Neurosurg 2019 May 24;132(6):1706-1714. Epub 2019 May 24.

1Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover.

Objective: 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PpIX) fluorescence is an effective surgical adjunct for the intraoperative identification of tumor tissue during resection of high-grade gliomas. The use of 5-ALA-induced PpIX fluorescence in glioblastoma (GBM) has been shown to double the extent of gross-total resection and 6-month progression-free survival. The heterogeneity of 5-ALA-induced PpIX fluorescence observed during surgery presents a technical and diagnostic challenge when utilizing this tool intraoperatively. While some regions show bright fluorescence after 5-ALA administration, other regions do not, despite that both regions of the tumor may be histopathologically indistinguishable. The authors examined the biological basis of this heterogeneity using computational methods.

Methods: The authors collected both fluorescent and nonfluorescent GBM specimens from a total of 14 patients undergoing surgery and examined their gene expression profiles.

Results: In this study, the authors found that the gene expression patterns characterizing fluorescent and nonfluorescent GBM surgical specimens were profoundly different and were associated with distinct cellular functions and different biological pathways. Nonfluorescent tumor tissue tended to resemble the neural subtype of GBM; meanwhile, fluorescent tumor tissue did not exhibit a prominent pattern corresponding to known subtypes of GBM. Consistent with this observation, neural GBM samples from The Cancer Genome Atlas database exhibited a significantly lower fluorescence score than nonneural GBM samples as determined by a fluorescence gene signature developed by the authors.

Conclusions: These results provide a greater understanding regarding the biological basis of differential fluorescence observed intraoperatively and can provide a basis to identify novel strategies to maximize the effectiveness of fluorescence agents.
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http://dx.doi.org/10.3171/2019.2.JNS183128DOI Listing
May 2019

Glioma Cell Secretion: A Driver of Tumor Progression and a Potential Therapeutic Target.

Cancer Res 2018 11 17;78(21):6031-6039. Epub 2018 Oct 17.

Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire.

Cellular secretion is an important mediator of cancer progression. Secreted molecules in glioma are key components of complex autocrine and paracrine pathways that mediate multiple oncogenic pathologies. In this review, we describe tumor cell secretion in high-grade glioma and highlight potential novel therapeutic opportunities. .
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http://dx.doi.org/10.1158/0008-5472.CAN-18-0345DOI Listing
November 2018

Inflammasomes: An Emerging Mechanism Translating Environmental Toxicant Exposure Into Neuroinflammation in Parkinson's Disease.

Toxicol Sci 2018 11;166(1):3-15

Department of Molecular and Systems Biology.

Evidence indicates that complex gene-environment interactions underlie the incidence and progression of Parkinson's disease (PD). Neuroinflammation is a well-characterized feature of PD widely believed to exacerbate the neurodegenerative process. Environmental toxicants associated with PD, such as pesticides and heavy metals, can cause cellular damage and stress potentially triggering an inflammatory response. Toxicant exposure can cause stress and damage to cells by impairing mitochondrial function, deregulating lysosomal function, and enhancing the spread of misfolded proteins. These stress-associated mechanisms produce sterile triggers such as reactive oxygen species (ROS) along with a variety of proteinaceous insults that are well documented in PD. These associations provide a compelling rationale for analysis of sterile inflammatory mechanisms that may link environmental exposure to neuroinflammation and PD progression. Intracellular inflammasomes are cytosolic assemblies of proteins that contain pattern recognition receptors, and a growing body of evidence implicates the association between inflammasome activation and neurodegenerative disease. Characterization of how inflammasomes may function in PD is a high priority because the majority of PD cases are sporadic, supporting the widely held belief that environmental exposure is a major factor in disease initiation and progression. Inflammasomes may represent a common mechanism that helps to explain the strong association between exposure and PD by mechanistically linking environmental toxicant-driven cellular stress with neuroinflammation and ultimately cell death.
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http://dx.doi.org/10.1093/toxsci/kfy219DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6659017PMC
November 2018

expression in mesencephalic neurons and characterization of a rare polymorphism associated with decreased risk of Parkinson's disease.

NPJ Parkinsons Dis 2018 15;4:24. Epub 2018 Aug 15.

1Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth and Dartmouth-Hitchcock Medical Center, Lebanon, NH USA.

Neuroinflammation is a well-characterized pathophysiology occurring in association with the progression of Parkinson's disease. Characterizing the cellular and molecular basis of neuroinflammation is critical to understanding its impact on the incidence and progression of PD and other neurologic disorders. Inflammasomes are intracellular pro-inflammatory pattern-recognition receptors capable of initiating and propagating inflammation. These cellular complexes are well characterized in the innate immune system and activity of the NLRP3 inflammasome has been reported in microglia. NLRP3 inflammasome activity has been associated with Alzheimer's disease, and recent reports, from our laboratory and others, indicate that is required for neuroinflammation and nigral cell loss in animal models of PD. has not yet been characterized in PD patients. Here we characterize in PD using immunohistologic and genetic approaches. Histologic studies revealed elevated expression in mesencephalic neurons of PD patients. Analysis of exome sequencing data for genetic variation of identified multiple single-nucleotide polymorphisms (SNPs) including rs7525979 that was associated with a significantly reduced risk of developing PD. Mechanistic studies conducted in HEK293 cells indicated that the synonymous SNP, rs7525979, alters the efficiency of translation impacting NLRP3 protein stability, ubiquitination state, and solubility. These data provide evidence that dopaminergic neurons are a cell-of-origin for inflammasome activity in PD and are consistent with recent animal studies, suggesting that inflammasome activity may impact the progression of PD.
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http://dx.doi.org/10.1038/s41531-018-0061-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6093937PMC
August 2018

Editor's Highlight: Nlrp3 Is Required for Inflammatory Changes and Nigral Cell Loss Resulting From Chronic Intragastric Rotenone Exposure in Mice.

Toxicol Sci 2017 09;159(1):64-75

Department of Molecular and Systems Biology.

Complex interactions between genetic and environmental factors are widely believed to underlie the incidence and progression of Parkinson's disease (PD). Rotenone is a naturally occurring metabolic toxin employed as an insecticide and piscicide identified as a risk factor for the development of PD in agricultural workers. The Nlrp3 inflammasome is an intracellular mediator that can initiate an inflammatory cascade in response to cellular stress. Reports by others indicating that NLRP3 expression was detectable in tissues obtained from Alzheimer's disease patients and that the PD-associated protein α-synuclein could activate inflammasomes in cultured glial cells, prompted us to test the prediction that Nlrp3 was required for the development of Parkinson's-like changes resulting from rotenone exposure in mice. We exposed wild type and Nlrp3-/- mice to chronic low doses of intragastric rotenone and conducted longitudinal behavioral and serum cytokine analysis followed by evaluation of neuroinflammatory and neurodegenerative endpoints in brain tissues. We observed progressive rotenone-dependent changes in serum cytokine levels and circulating leukocytes in wild type mice not observed in Nlrp3-/- mice. Analysis of brain tissues revealed Nlrp3-dependent neuroinflammation and nigral cell loss in mice exposed to rotenone as compared with mice exposed to vehicle alone. Together, our findings provide compelling evidence of a role for Nlrp3 in nigral degeneration and neuroinflammation resulting from systemic rotenone exposure and suggest that the suppression of NLRP3 activity may be a rational neuroprotective strategy for toxin-associated PD.
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http://dx.doi.org/10.1093/toxsci/kfx117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5837210PMC
September 2017

ID2 promotes survival of glioblastoma cells during metabolic stress by regulating mitochondrial function.

Cell Death Dis 2017 02 16;8(2):e2615. Epub 2017 Feb 16.

Norris Cotton Cancer Center, Lebanon, NH 03756, USA.

Tumor cells proliferate in cellular environments characterized by a lack of optimal tissue organization resulting oftentimes in compromised cellular metabolism affecting nutrition, respiration, and energetics. The response of tumor cells to adverse environmental conditions is a key feature affecting their pathogenicity. We found that inhibitor of DNA binding 2 (ID2) expression levels significantly correlate with the ability of glioblastoma (GBM)-derived cell lines to survive glucose deprivation. ID2 suppressed mitochondrial oxidative respiration and mitochondrial ATP production by regulating the function of mitochondrial electron transport chain (mETC) complexes, resulting in reduced superoxide and reactive oxygen species (ROS) production from mitochondria. ID2 suppression of ROS production reduced mitochondrial damage and enhanced tumor cell survival during glucose deprivation. Bioinformatics analysis of GBM gene expression data from The Cancer Genome Atlas (TCGA) database revealed that expression of ID2 mRNA is unique among ID gene family members in correlating with the expression of nuclear genes involved in mitochondrial energy metabolism and assembly of mETC. Our data indicate that the expression level of ID2 in GBM cells can predict the sensitivity of GBM-derived tumor cells to decreased glucose levels. Low levels of ID2 expression in human GBM tissues may identify a clinical group in which metabolic targeting of glycolytic pathways can be expected to have the greatest therapeutic efficacy.
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http://dx.doi.org/10.1038/cddis.2017.14DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5386464PMC
February 2017

Insulin-Mediated Signaling Facilitates Resistance to PDGFR Inhibition in Proneural hPDGFB-Driven Gliomas.

Mol Cancer Ther 2017 04 30;16(4):705-716. Epub 2017 Jan 30.

Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire;

Despite abundant evidence implicating receptor tyrosine kinases (RTK), including the platelet-derived growth factor receptor (PDGFR), in the pathogenesis of glioblastoma (GBM), the clinical use of RTK inhibitors in this disease has been greatly compromised by the rapid emergence of therapeutic resistance. To study the resistance of proneural gliomas that are driven by a PDGFR-regulated pathway to targeted tyrosine kinase inhibitors, we utilized a mouse model of proneural glioma in which mice develop tumors that become resistant to PDGFR inhibition. We found that tumors resistant to PDGFR inhibition required the expression and activation of the insulin receptor (IR)/insulin growth-like factor receptor (IGF1R) for tumor cell proliferation and survival. Cotargeting IR/IGF1R and PDGFR decreased the emergence of resistant clones Our findings characterize a novel model of glioma recurrence that implicates the IR/IGF1R signaling axis in mediating the development of resistance to PDGFR inhibition and provide evidence that IR/IGF1R signaling is important in the recurrence of the proneural subtype of glioma in which PDGF/PDGFR is most commonly expressed at a high level. .
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http://dx.doi.org/10.1158/1535-7163.MCT-16-0616DOI Listing
April 2017

Phosphorylation Regulates Id2 Degradation and Mediates the Proliferation of Neural Precursor Cells.

Stem Cells 2016 05 1;34(5):1321-31. Epub 2016 Feb 1.

Pharmacology and Toxicology, Norris Cotton Cancer Center, One Medical Center Drive, Lebanon, NH, 03756.

Inhibitor of DNA binding proteins (Id1-Id4) function to inhibit differentiation and promote proliferation of many different cell types. Among the Id family members, Id2 has been most extensively studied in the central nervous system (CNS). Id2 contributes to cultured neural precursor cell (NPC) proliferation as well as to the proliferation of CNS tumors such as glioblastoma that are likely to arise from NPC-like cells. We identified three phosphorylation sites near the N-terminus of Id2 in NPCs. To interrogate the importance of Id2 phosphorylation, Id2(-/-) NPCs were modified to express wild type (WT) Id2 or an Id2 mutant protein that could not be phosphorylated at the identified sites. We observed that NPCs expressing this mutant lacking phosphorylation near the N-terminus had higher steady-state levels of Id2 when compared to NPCs expressing WT Id2. This elevated level was the result of a longer half-life and reduced proteasome-mediated degradation. Moreover, NPCs expressing constitutively de-phosphorylated Id2 proliferated more rapidly than NPCs expressing WT Id2, a finding consistent with the well-characterized function of Id2 in driving proliferation. Observing that phosphorylation of Id2 modulates the degradation of this important cell-cycle regulator, we sought to identify a phosphatase that would stabilize Id2 enhancing its activity in NPCs and extended our analysis to include human glioblastoma-derived stem cells (GSCs). We found that expression of the phosphatase PP2A altered Id2 levels. Our findings suggest that inhibition of PP2A may be a novel strategy to regulate the proliferation of normal NPCs and malignant GSCs by decreasing Id2 levels. Stem Cells 2016;34:1321-1331.
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http://dx.doi.org/10.1002/stem.2291DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5024556PMC
May 2016

Id2 mediates oligodendrocyte precursor cell maturation arrest and is tumorigenic in a PDGF-rich microenvironment.

Cancer Res 2014 Mar 14;74(6):1822-32. Epub 2014 Jan 14.

Authors' Affiliations: Norris Cotton Cancer Center; Departments of Genetics; Pediatrics; and Pharmacology and Toxicology, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire.

Maturation defects occurring in adult tissue progenitor cells have the potential to contribute to tumor development; however, there is little experimental evidence implicating this cellular mechanism in the pathogenesis of solid tumors. Inhibitor of DNA-binding 2 (Id2) is a transcription factor known to regulate the proliferation and differentiation of primitive stem and progenitor cells. Id2 is derepressed in adult tissue neural stem cells (NSC) lacking the tumor suppressor Tp53 and modulates their proliferation. Constitutive expression of Id2 in differentiating NSCs resulted in maturation-resistant oligodendroglial precursor cells (OPC), a cell population implicated in the initiation of glioma. Mechanistically, Id2 overexpression was associated with inhibition of the Notch effector Hey1, a bHLH transcription factor that we here characterize as a direct transcriptional repressor of the oligodendroglial lineage determinant Olig2. Orthotopic inoculation of NSCs with enhanced Id2 expression into brains of mice engineered to express platelet-derived growth factor in the central nervous system resulted in glioma. These data implicate a mechanism of altered NSC differentiation in glioma development and characterize a novel mouse model that reflects key characteristics of the recently described proneural subtype of glioblastoma multiforme. Such findings support the emerging concept that the cellular and molecular characteristics of tumor cells are linked to the transformation of distinct subsets of adult tissue progenitors.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5061294PMC
http://dx.doi.org/10.1158/0008-5472.CAN-13-1839DOI Listing
March 2014

Behavioral abnormalities and Parkinson's-like histological changes resulting from Id2 inactivation in mice.

Dis Model Mech 2013 May 20;6(3):819-27. Epub 2012 Dec 20.

Norris Cotton Cancer Center and Department of Pediatrics, Geisel School of Medicine at Dartmouth, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, USA.

Characterizing dopaminergic neuronal development and function in novel genetic animal models might uncover strategies for researchers to develop disease-modifying treatments for neurologic disorders. Id2 is a transcription factor expressed in the developing central nervous system. Id2(-/-) mice have fewer dopaminergic neurons in the olfactory bulb and reduced olfactory discrimination, a pre-clinical marker of Parkinson's disease. Here, we summarize behavioral, histological and in vitro molecular biological analyses to determine whether midbrain dopaminergic neurons are affected by Id2 loss. Id2(-/-) mice were hyperactive at 1 and 3 months of age, but by 6 months showed reduced activity. Id2(-/-) mice showed age-dependent histological alterations in dopaminergic neurons of the substantia nigra pars compacta (SNpC) associated with changes in locomotor activity. Reduced dopamine transporter (DAT) expression was observed at early ages in Id2(-/-) mice and DAT expression was dependent on Id2 expression in an in vitro dopaminergic differentiation model. Evidence of neurodegeneration, including activated caspase-3 and glial infiltration, were noted in the SNpC of older Id2(-/-) mice. These findings document a novel role for Id2 in the maintenance of midbrain dopamine neurons. The Id2(-/-) mouse should provide unique opportunities to study the progression of neurodegenerative disorders involving the dopamine system.
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http://dx.doi.org/10.1242/dmm.010041DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3634664PMC
May 2013

p53 directly represses Id2 to inhibit the proliferation of neural progenitor cells.

Stem Cells 2011 Jul;29(7):1090-101

Norris Cotton Cancer Center, Dartmouth Medical School, Hanover, New Hampshire, USA.

Neural progenitor cells (NPCs) have the capacity to proliferate and give rise to all major central nervous system cell types and represent a possible cell of origin in gliomagenesis. Deletion of the tumor suppressor gene Tp53 (p53) results in increased proliferation and self-renewal of NPCs and is a common genetic mutation found in glioma. We have identified inhibitor of DNA binding 2 (Id2) as a novel target gene directly repressed by p53 to maintain normal NPC proliferation. p53((-/-)) NPCs express elevated levels of Id2 and suppression of Id2 expression is sufficient to inhibit the increased proliferation and self-renewal which results from p53 loss. Elevated expression of Id2 in wild-type NPCs phenocopies the behavior of p53((-/-)) NPCs by enhancing NPC proliferation and self-renewal. Interestingly, p53 directly binds to a conserved site within the Id2 promoter to mediate these effects. Finally, we have identified elevated Id2 expression in glioma cell lines with mutated p53 and demonstrated that constitutive expression of Id2 plays a key role in the proliferation of glioma stem-like cells. These findings indicate that Id2 functions as a proproliferative gene that antagonizes p53-mediated cell cycle regulation in NPCs and may contribute to the malignant proliferation of glioma-derived tumor stem cells.
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http://dx.doi.org/10.1002/stem.660DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3647692PMC
July 2011

Id2 is required for specification of dopaminergic neurons during adult olfactory neurogenesis.

J Neurosci 2008 Dec;28(52):14074-86

Norris Cotton Cancer Center, Dartmouth Medical School, Lebanon, New Hampshire 03756, USA.

Understanding the biology of adult neural stem cells has important implications for nervous system development and may contribute to our understanding of neurodegenerative disorders and their treatment. We have characterized the process of olfactory neurogenesis in adult mice lacking inhibitor of DNA binding 2(-/-) (Id2(-/-)). We found a diminished olfactory bulb containing reduced numbers of granular and periglomerular neurons with a distinct paucity of dopaminergic periglomerular neurons. While no deficiency of the stem cell compartment was detectable, migrating neuroblasts in Id2(-/-) mutant mice prematurely undergo astroglial differentiation within a disorganized rostral migratory stream. Further, when evaluated in vitro loss of Id2 results in decreased proliferation of neural progenitors and decreased expression of the Hes1 and Ascl1 (Mash1) transcription factors, known mediators of neuronal differentiation. These data support a novel role for sustained Id2 expression in migrating neural progenitors mediating olfactory dopaminergic neuronal differentiation in adult animals.
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http://dx.doi.org/10.1523/JNEUROSCI.3188-08.2008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2692601PMC
December 2008

A novel mechanism of transcriptional repression of p27kip1 through Notch/HRT2 signaling in vascular smooth muscle cells.

Thromb Haemost 2006 Sep;96(3):361-70

Center for Molecular Medicine, Maine Medical Center Research Institute, 81 Research Drive, Scarborough, Maine 04074, USA.

Vascular smooth muscle cell (VSMC) proliferation occurs in vascular obstructive events such as atherosclerosis and restenosis. We previously showed that Notch receptors are induced in smooth muscle cells during vascular remodeling. Our goal was to determine the mechanisms employed by Notch signaling to regulate proliferation. Activation of Notch1 and Notch4 induced the VSMC-selective target genes HRT1 and HRT2, promoted cell cycle transit in smooth muscle cells, and led to loss of density-dependent growth inhibition. This was associated with a reduction in levels of the cyclin-dependent kinase inhibitor (cdk) p27(kip1). Over-expression of p27(kip1) resulted in a dose-dependent rescue of the Notch-induced phenotype and exit from the cell cycle. In addition, HRT2 expression was sufficient to promote S-phase entry, and we demonstrate that HRT2 interacts directly with the p27(kip1) promoter to repress transcription. Transcriptional repression occurred within the approximately 774 bp minimal p27(kip1) promoter region and mutational analysis demonstrated that repression is largely dependent on a conserved class-C domain. Our data show that Notch signaling acts to promote a proliferative phenotype in VSMC by modulation of the G1/S-phase checkpoint. In addition, we define a novel mechanism by which the Notch effector, HRT2, interacts directly with the class-C domain of the p27(kip1) promoter, repressing its expression. These studies identify a novel transcriptional target of HRT2, and show that Notch effectors directly control cell cycle regulatory components. We suggest that this mechanism is relevant to hyperproliferative states in VSMC seen during vascular remodeling and repair.
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http://dx.doi.org/10.1160/TH06-04-0224DOI Listing
September 2006

Integration of Notch 1 and calcineurin/NFAT signaling pathways in keratinocyte growth and differentiation control.

Dev Cell 2005 May;8(5):665-76

Department of Biochemistry, Lausanne University, Epalinges, Switzerland.

The Notch and Calcineurin/NFAT pathways have both been implicated in control of keratinocyte differentiation. Induction of the p21(WAF1/Cip1) gene by Notch 1 activation in differentiating keratinocytes is associated with direct targeting of the RBP-Jkappa protein to the p21 promoter. We show here that Notch 1 activation functions also through a second Calcineurin-dependent mechanism acting on the p21 TATA box-proximal region. Increased Calcineurin/NFAT activity by Notch signaling involves downregulation of Calcipressin, an endogenous Calcineurin inhibitor, through a HES-1-dependent mechanism. Besides control of the p21 gene, Calcineurin contributes significantly to the transcriptional response of keratinocytes to Notch 1 activation, both in vitro and in vivo. In fact, deletion of the Calcineurin B1 gene in the skin results in a cyclic alopecia phenotype, associated with altered expression of Notch-responsive genes involved in hair follicle structure and/or adhesion to the surrounding mesenchyme. Thus, an important interconnection exists between Notch 1 and Calcineurin-NFAT pathways in keratinocyte growth/differentiation control.
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http://dx.doi.org/10.1016/j.devcel.2005.02.016DOI Listing
May 2005
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