scholarly journals Neurodegeneration Caused by S1P-Lyase Deficiency Involves Calcium-Dependent Tau Pathology and Abnormal Histone Acetylation

Cells ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 2189 ◽  
Author(s):  
Shah Alam ◽  
Antonia Piazzesi ◽  
Mariam Abd El Fatah ◽  
Maren Raucamp ◽  
Gerhild van Echten-Deckert
Keyword(s):  
Histone Acetylation ◽  
Brain Health ◽  
Gene Encoding ◽  
Calcium Dependent ◽  
Sphingosine Kinase 2 ◽  
Calcium Chelation ◽  
Sphingosine 1 Phosphate ◽  
S1p Lyase ◽  
The Brain ◽  
Neuronal Autophagy

We have shown that sphingosine 1-phosphate (S1P) generated by sphingosine kinase 2 (SK2) is toxic in neurons lacking S1P-lyase (SGPL1), the enzyme that catalyzes its irreversible cleavage. Interestingly, patients harboring mutations in the gene encoding this enzyme (SGPL1) often present with neurological pathologies. Studies in a mouse model with a developmental neural-specific ablation of SGPL1 (SGPL1fl/fl/Nes) confirmed the importance of S1P metabolism for the presynaptic architecture and neuronal autophagy, known to be essential for brain health. We now investigated in SGPL1-deficient murine brains two other factors involved in neurodegenerative processes, namely tau phosphorylation and histone acetylation. In hippocampal and cortical slices SGPL1 deficiency and hence S1P accumulation are accompanied by hyperphosphorylation of tau and an elevated acetylation of histone3 (H3) and histone4 (H4). Calcium chelation with BAPTA-AM rescued both tau hyperphosphorylation and histone acetylation, designating calcium as an essential mediator of these (patho)physiological functions of S1P in the brain. Studies in primary cultured neurons and astrocytes derived from SGPL1fl/fl/Nes mice revealed hyperphosphorylated tau only in SGPL1-deficient neurons and increased histone acetylation only in SGPL1-deficient astrocytes. Both could be reversed to control values with BAPTA-AM, indicating the close interdependence of S1P metabolism, calcium homeostasis, and brain health.

scholarly journals S1P Lyase Regulation of Thymic Egress and Oncogenic Inflammatory Signaling

2017 ◽  
Vol 2017 ◽  
pp. 1-19 ◽  
Author(s):  
Ashok Kumar ◽  
Jesus Zamora-Pineda ◽  
Emilie Degagné ◽  
Julie D. Saba
Keyword(s):  
Immune Cell ◽  
Current Evidence ◽  
Cell Trafficking ◽  
Inherited Disease ◽  
Gene Encoding ◽  
Surface Receptors ◽  
Sphingosine 1 Phosphate ◽  
Lymphocyte Egress ◽  
S1p Lyase ◽  
Inherited Mutations

Sphingosine-1-phosphate (S1P) is a potent lipid signaling molecule that regulates pleiotropic biological functions including cell migration, survival, angiogenesis, immune cell trafficking, inflammation, and carcinogenesis. It acts as a ligand for a family of cell surface receptors. S1P concentrations are high in blood and lymph but low in tissues, especially the thymus and lymphoid organs. S1P chemotactic gradients are essential for lymphocyte egress and other aspects of physiological cell trafficking. S1P is irreversibly degraded by S1P lyase (SPL). SPL regulates lymphocyte trafficking, inflammation and other physiological and pathological processes. For example, SPL located in thymic dendritic cells acts as a metabolic gatekeeper that controls the normal egress of mature T lymphocytes from the thymus into the circulation, whereas SPL deficiency in gut epithelial cells promotes colitis and colitis-associated carcinogenesis (CAC). Recently, we identified a complex syndrome comprised of nephrosis, adrenal insufficiency, and immunological defects caused by inherited mutations in human SGPL1, the gene encoding SPL. In the present article, we review current evidence supporting the role of SPL in thymic egress, inflammation, and cancer. Lastly, we summarize recent progress in understanding other SPL functions, its role in inherited disease, and SPL targeting for therapeutic purposes.

scholarly journals Mechanism of sphingosine 1-phosphate clearance from blood

2020 ◽  
Vol 477 (5) ◽  
pp. 925-935 ◽  
Author(s):  
Yugesh Kharel ◽  
Tao Huang ◽  
Anita Salamon ◽  
Thurl E. Harris ◽  
Webster L. Santos ◽  
...  
Keyword(s):  
Immune Cell ◽  
General Mechanism ◽  
Concentration Gradients ◽  
Sphingosine Kinase 2 ◽  
Sphingosine 1 Phosphate ◽  
Degradative Enzymes ◽  
High Altitude Acclimatization ◽  
Endothelial Integrity ◽  
S1p Lyase

The interplay of sphingosine 1-phosphate (S1P) synthetic and degradative enzymes as well as S1P exporters creates concentration gradients that are a fundamental to S1P biology. Extracellular S1P levels, such as in blood and lymph, are high relative to cellular S1P. The blood-tissue S1P gradient maintains endothelial integrity while local S1P gradients influence immune cell positioning. Indeed, the importance of S1P gradients was recognized initially when the mechanism of action of an S1P receptor agonist used as a medicine for multiple sclerosis was revealed to be inhibition of T-lymphocytes’ recognition of the high S1P in efferent lymph. Furthermore, the increase in erythrocyte S1P in response to hypoxia influences oxygen delivery during high altitude acclimatization. However, understanding of how S1P gradients are maintained is incomplete. For example, S1P is synthesized but is only slowly metabolized by blood yet circulating S1P turns over quickly by an unknown mechanism. Prompted by the counterintuitive observation that blood S1P increases markedly in response to inhibition S1P synthesis (by sphingosine kinase 2 (SphK2)), we studied mice wherein several tissues were made deficient in either SphK2 or S1P degrading enzymes. Our data reveal a mechanism whereby S1P is de-phosphorylated at the hepatocyte surface and the resulting sphingosine is sequestered by SphK phosphorylation and in turn degraded by intracellular S1P lyase. Thus, we identify the liver as the primary site of blood S1P clearance and provide an explanation for the role of SphK2 in this process. Our discovery suggests a general mechanism whereby S1P gradients are shaped.

Apoptotic cell extrusion depends on single-cell synthesis of sphingosine-1-phosphate by sphingosine kinase 2

2021 ◽  
Vol 1866 (4) ◽  
pp. 158888
Author(s):  
Bruno Jaime Santacreu ◽  
Daniela Judith Romero ◽  
Lucila Gisele Pescio ◽  
Estefanía Tarallo ◽  
Norma Beatriz Sterin-Speziale ◽  
...  
Keyword(s):  
Single Cell ◽  
Apoptotic Cell ◽  
Sphingosine Kinase ◽  
Sphingosine Kinase 2 ◽  
Sphingosine 1 Phosphate ◽  
Cell Synthesis ◽  
Cell Extrusion

scholarly journals Social Volunteering in Aging Adults Increases Regions of the Amygdala and Correlates With Enhanced Generativity

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 795-795
Author(s):  
Michelle Carlson
Keyword(s):  
Social Engagement ◽  
Controlled Trial ◽  
Well Being ◽  
Health Study ◽  
Brain Health ◽  
Volunteer Program ◽  
Intention To Treat ◽  
Intervention Impact ◽  
Aging Adults ◽  
The Brain

Abstract The Brain Health Study (BHS) of the Baltimore Experience Corps Trial (BECT) examined whether a randomized, controlled trial of an intergenerational social volunteer program, entitled Experience Corps, increased subregions of the amygdala related to socioemotional memory and risk for Alzheimer’s disease in aging adults. We further assessed functional correlates of these intervention-related changes and changes in aging adults’ developmental need to be generative, or, to give back to the well-being of others. The BHS simultaneously randomized 112 men and women (59 intervention; 53 control) within BECT to evaluate intervention impact on biomarkers of brain health at baseline and annual follow-ups during the two-year trial. Intention-to-treat analyses revealed program-specific increases in the shape of the centromedial and basomedial regions of the left amygdala (p’s≤0.05 adjusted), which were correlated with increases in generativity (p’s =0.06). Meaningful social engagement buffered amygdalar declines important to preservation of emotionally salient memory and risk for dementia. Part of a symposium sponsored by Brain Interest Group.

scholarly journals Characterization of calcium-dependent membrane binding proteins of brain cortex

1985 ◽  
Vol 229 (3) ◽  
pp. 587-593 ◽  
Author(s):  
A R Rhoads ◽  
M Lulla ◽  
P B Moore ◽  
C E Jackson
Keyword(s):  
Brain Cortex ◽  
Peptide Mapping ◽  
Bovine Brain ◽  
Particulate Fraction ◽  
Structural Homology ◽  
One Dimensional ◽  
Calcium Dependent ◽  
Stokes Radius ◽  
The Brain

Proteins of Mr 68 000, 34 000 and 32 000 were selectively extracted by EGTA from brain cortex. The three proteins that were extracted along with calmodulin were acidic, monomeric, and did not exhibit structural homology, as demonstrated by one-dimensional peptide mapping. The Mr-68 000 protein was purified to homogeneity and had a Stokes radius of 3.54 nm and S20,W value of 5.1S. Purified calmodulin, Mr-68 000 protein and two proteins of Mr 34 000 and Mr 32 000, interacted with the brain particulate fraction, with half-maximal binding occurring at 3.5 microM, 8.3 microM and 150 microM-Ca2+ respectively. Proteins were bound independently of each other and calmodulin. Pretreatment of the particulate fraction with trypsin prevented the Ca2+-dependent binding of calmodulin; however, the binding of the Mr-68 000 protein or the Mr−32 000 and −34 000 proteins was unaffected. The Mr-68 000 protein of bovine brain did not cross-react immunologically with Mr-67 000 calcimedin from chicken gizzard.

Abstract MP16: Excessive White Matter Hyperintensity Burden and Functional Outcomes After Acute Ischemic Stroke

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Sungmin Hong ◽  
Anne-katrin Giese ◽  
Markus D Schirmer ◽  
Adrian V Dalca ◽  
Anna Bonkhoff ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
White Matter ◽  
Acute Ischemic Stroke ◽  
Functional Outcomes ◽  
Life Time ◽  
Stroke Recovery ◽  
White Matter Hyperintensity ◽  
Brain Health ◽  
Stroke Outcomes ◽  
The Brain

Objective: Ability of the brain to recover after an acute ischemic stroke (AIS) is linked to the pre-stroke burden of white matter hyperintensity (WMH), a radiographic marker of brain health. We sought to determine the excessive WMH burden in an AIS population and investigate its association with 3-month stroke outcomes. Data: We used 2,435 subjects from the MRI-GENIE study. Three-month functional outcomes of 872 subjects among those subjects were measured by 90-day modified Ranking Scale (mRS). Methods: We automatically quantified WMH volume (WMHv) on FLAIR images and adjusted for a brain volume. We modeled a trend using the factor analysis (FA) log-linear regression using age, sex, atrial fibrillation, diabetes, hypertension, coronary artery disease and smoking as input variables. We categorized three WMH burden groups based on the conditional probability given by the model (LOW: lower 33%, MED: middle 34%, and HIGH: upper 33%). The subgroups were compared with respect to mRS (median and dichotomized odds ratio (OR) (good/poor: mRS 0-2/3-6)). Results: Five FA components out of seven with significant relationship to WMHv (p<0.001) were used for the regression modeling (R 2 =0.359). The HIGH group showed higher median (median=2, IQR=2) mRS score than LOW (median=1, IQR=1) and MED (median=1, IQR=1). The odds (OR) of good AIS outcome for LOW and MED were 1.8 (p=0.0001) and 1.6 (p=0.006) times higher than HIGH, respectively. Conclusion: Once accounted for clinical covariates, the excessive WMHv was associated with worse 3-month stroke outcomes. These data suggest that a life-time of injury to the white matter reflected in WMH is an important factor for stroke recovery and an indicator of the brain health.

scholarly journals Big data to smart data in Alzheimer's disease: The brain health modeling initiative to foster actionable knowledge

2016 ◽  
Vol 12 (9) ◽  
pp. 1014-1021 ◽  
Author(s):  
Hugo Geerts ◽  
Penny A. Dacks ◽  
Viswanath Devanarayan ◽  
Magali Haas ◽  
Zaven S. Khachaturian ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Big Data ◽  
Brain Health ◽  
Actionable Knowledge ◽  
Smart Data ◽  
The Brain
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