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EOH Departmental Calendar

Thu 11/21/2019 11:00AM - 12:00PM
EOH Journal Club
Association of Environmental Toxins With Amyotrophic Lateral Sclerosis EOH Journal Club
Association of Environmental Toxins With Amyotrophic Lateral Sclerosis
Thu 11/21/2019 11:00AM - 12:00PM
4140 Public Health, Young Seminar Room

Presenter: Fan Wu

Paper: Association of Environmental Toxins With Amyotrophic Lateral Sclerosis

Authors: Feng-Chiao Su,PhD; Stephen A. Goutman,MD; Sergey Chernyak,PhD; Bhramar Mukherjee,PhD; Brian C. Callaghan,MD; Stuart Batterman,PhD; Eva L. Feldman,MD,PhD

Persistent environmental pollutants may represent a modifiable risk factor involved in the gene-time-environment hypothesis in amyotrophic lateral sclerosis (ALS).

To evaluate the association of occupational exposures and environmental toxins on the odds of developing ALS in Michigan.

Case-control study conducted between 2011 and 2014
at a tertiary referral center for ALS. Cases were patients diagnosed as having definitive,
probable, probable with laboratory support, or possible ALS by revised El Escorial criteria;
controls were excluded if they were diagnosed as having ALS or another neurodegenerative
condition or if they had a family history of ALS in a first- or second-degree blood relative.
Participants completed a survey assessing occupational and residential exposures. Blood
concentrations of 122 persistent environmental pollutants, including organochlorine
pesticides (OCPs), polychlorinated biphenyls (PCBs), and brominated flame retardants
(BFRs), were measured using gas chromatography–mass spectrometry. Multivariable models
with self-reported occupational exposures in various exposure time windows and
environmental toxin blood concentrations were separately fit by logistic regression models.
Concordance between the survey data and pollutant measurements was assessed using the
nonparametric Kendall τ correlation coefficient.

Occupational and residential exposures to environmental toxins, and blood concentrations of 122 persistent environmental pollutants, including OCPs,
PCBs, and BFRs.

Participants included 156 cases (mean [SD] age, 60.5 [11.1] years; 61.5%male) and 128 controls (mean [SD] age, 60.4 [9.4] years; 57.8%male); among them, 101 cases and 110 controls had complete demographic and pollutant data. Survey data revealed that reported
pesticide exposure in the cumulative exposure windows was significantly associated with ALS
(odds ratio [OR] = 5.09; 95%CI, 1.85-13.99; P = .002). Military service was also associated
with ALS in 2 time windows (exposure ever happened in entire occupational history:
OR = 2.31; 95%CI, 1.02-5.25; P = .046; exposure ever happened 10-30 years ago: OR = 2.18;
95%CI, 1.01-4.73; P = .049). A multivariable model of measured persistent environmental
pollutants in the blood, representing cumulative occupational and residential exposure,
showed increased odds of ALS for 2 OCPs (pentachlorobenzene: OR = 2.57; 95%CI, 1.31-5.02;
P = .006; and cis-chlordane: OR = 6.51; 95%CI, 2.05-20.73; P = .002) and 1 PCB (PCB 151:
OR = 1.66; 95%CI, 1.03-2.67; P = .04. There was modest concordance between survey data
and the measurements of persistent environmental pollutants in blood; significant Kendall τ
correlation coefficients ranged from −0.18 (Dacthal and “use pesticides to treat home or
yard”) to 0.24 (trans-nonachlor and “store lawn care products in garage”).

In this study, persistent environmental pollutants measured in blood were significantly associated with ALS and may represent modifiable ALS disease risk

4140 Public Health, Young Seminar Room
Thu 12/5/2019 11:00AM - 12:00PM
EOH Journal Club
Protein Arginine Methyltransferase 4 (PRMT4) mediates lymphopenia in experimental sepsis EOH Journal Club
Protein Arginine Methyltransferase 4 (PRMT4) mediates lymphopenia in experimental sepsis
Thu 12/5/2019 11:00AM - 12:00PM
4140 Public Health, Young Seminar Room

Presenter: Rushikesh Deshpande

Paper: Protein Arginine Methyltransferase 4 (PRMT4) mediates lymphopenia in experimental sepsis

Authors: Yandong Lai, Xiuying Li, Tiao Li, Yan Chen, Chen Long, Toru Nyunoya, Kong Chen,Georgios D. Kitsios,Seyed Mehdi Nouraie,Yingze Zhang, Bryan J. McVerry, Janet S. Lee,Rama K. Mallampalli, and Chunbin Zou

Onehallmark of sepsis is a reduced number of lymphocytes, termed lymphopenia,that occurs from decreased lymphocyte proliferation or increased cell death contributing to immune suppression. Histone modification enzymes regulate immunity by epigenetically modulating chromatin architecture, however, the role of these enzymes in lymphopenia remains elusive. In this study, we identified that a chromatin modulator Protein Arginine N-methyltransferase 4/Coactivator-Associated Arginine Methyltransferase 1 (PRMT4/ CARM1) that is elevated systemically inseptic patients and experimental sepsis, and is crucialfor inducing T-lymphocyte apoptosis.An E3 ubiquitin ligase SCFFBXO9 docks on PRMT4 via a phosphodegron to ubiquitinate the protein at K228 for ubiquitin proteasomal degradation.  High PRMT4 expression resulted from reduced levels of SCFFBXO9 that led to increased lymphocyte cell death after Escherichia coliorlipopolysaccharide(LPS) exposure. Ectopic expression of PRMT4 protein caused substantially mphocytedeathvia caspase 3 mediated cell death signaling, and knockout of PRMT4 abolished LPS mediated lymphocyte cell death. PRMT4 inhibition with a small molecule compound attenuated lymphocyte death in complementary models of sepsis. These findings demonstrate a previously uncharacterized role of a key chromatin modulator in lymphocytesurvival that may shed light on devising unique therapeutic modalities to lessen severity of septic immunosuppression.

4140 Public Health, Young Seminar Room

Recent Events

EOH Journal Club

EOH Journal Club - Spring 2018 - Emilie Castranio

Thursday 3/22 11:00AM - 12:00PM
4140 Public Health, Young Seminar Room
EOH Journal Club Seminar - Spring 2018

Date: Thursday March 22, 2018

Time: 11am - 12pm

Presenter: Emilie Castranio

Paper: ApoE4 markedly exacerbates tau-mediated neurodegeneration in a mouse model of tauopathy

Authors: Shi Y, Yamada K, Liddelow SA, Smith ST, Zhao L, Luo W, Tsai RM, Spina S, Grinberg LT, Rojas JC, Gallardo G, Wang K, Roh J, Robinson G, Finn MB, Jiang H, Sullivan PM, Baufeld C, Wood MW, Sutphen C, McCue L, Xiong C, Del-Aguila JL, Morris JC, Cruchaga C; Alzheimer’s Disease Neuroimaging Initiative, Fagan AM, Miller BL, Boxer AL, Seeley WW, Butovsky O, Barres BA, Paul SM, Holtzman DM.

Abstract: APOE4 is the strongest genetic risk factor for late-onset Alzheimer disease. ApoE4 increases brain amyloid-β pathology relative to other ApoE isoforms. However, whether APOE independently influences tau pathology, the other major proteinopathy of Alzheimer disease and other tauopathies, or tau-mediated neurodegeneration, is not clear. By generating P301S tau transgenic mice on either a human ApoE knock-in (KI) or ApoE knockout (KO) background, here we show that P301S/E4 mice have significantly higher tau levels in the brain and a greater extent of somatodendritic tau redistribution by three months of age compared with P301S/E2, P301S/E3, and P301S/EKO mice. By nine months of age, P301S mice with different ApoE genotypes display distinct phosphorylated tau protein (p-tau) staining patterns. P301S/E4 mice develop markedly more brain atrophy and neuroinflammation than P301S/E2 and P301S/E3 mice, whereas P301S/EKO mice are largely protected from these changes. In vitro, E4-expressing microglia exhibit higher innate immune reactivity after lipopolysaccharide treatment. Co-culturing P301S tau-expressing neurons with E4-expressing mixed glia results in a significantly higher level of tumour-necrosis factor-α (TNF-α) secretion and markedly reduced neuronal viability compared with neuron/E2 and neuron/E3 co-cultures. Neurons co-cultured with EKO glia showed the greatest viability with the lowest level of secreted TNF-α. Treatment of P301S neurons with recombinant ApoE (E2, E3, E4) also leads to some neuronal damage and death compared with the absence of ApoE, with ApoE4 exacerbating the effect. In individuals with a sporadic primary tauopathy, the presence of an ε4 allele is associated with more severe regional neurodegeneration. In individuals who are positive for amyloid-β pathology with symptomatic Alzheimer disease who usually have tau pathology, ε4-carriers demonstrate greater rates of disease progression. Our results demonstrate that ApoE affects tau pathogenesis, neuroinflammation, and tau-mediated neurodegeneration independently of amyloid-β pathology. ApoE4 exerts a 'toxic' gain of function whereas the absence of ApoE is protective.

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Last Updated On Monday, March 19, 2018 by Orbell, Adam W
Created On Thursday, February 22, 2018

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