The genetic and epigenetic profile of serum S100β in the Lothian Birth Cohort 1936 and its relationship to Alzheimer’s disease

Background: Circulating S100 calcium-binding protein (S100β) is a marker of brain inflammation that has been associated with a range of neurological conditions. To provide insight into the molecular regulation of S100β and its potential causal associations with Alzheimer’s disease, we carried out genome- and epigenome-wide association studies (GWAS/EWAS) of serum S100β levels in older adults and performed Mendelian randomisation with Alzheimer’s disease. Methods: GWAS (N=769, mean age 72.5 years, sd = 0.7) and EWAS (N=722, mean age 72.5 years, sd = 0.7) of S100β levels were performed in participants from the Lothian Birth Cohort 1936. Conditional and joint analysis (COJO) was used to identify independent loci. Expression quantitative trait locus (eQTL) analyses were performed for lead loci that had genome-wide significant associations with S100β. Bidirectional, two-sample Mendelian randomisation was used to test for causal associations between S100β and Alzheimer’s disease. Colocalisation between S100β and Alzheimer’s disease GWAS loci was also examined. Results: We identified 154 SNPs from chromosome 21 that associated (P<5x10-8) with S100β protein levels. The lead variant was located in the S100β gene (rs8128872, P=5.0x10-17). We found evidence that two independent causal variants existed for both transcription of S100β and S100β protein levels in our eQTL analyses. No CpG sites were associated with S100β levels at the epigenome-wide significant level (P<3.6x10-8); the lead probe was cg06833709 (P=5.8x10-6), which mapped to the LGI1 gene. There was no evidence of a causal association between S100β levels and Alzheimer’s disease or vice versa and no evidence for colocalisation between S100β and Alzheimer’s disease loci. Conclusions: These data provide insight into the molecular regulators of S100β levels. This context may aid in understanding the role of S100β in brain inflammation and neurological disease.

S100β protein levels as a parameter to assess the clinical development of adult patients with mild traumatic brain injury in Dr. Moewardi Public Hospital, Surakarta

Background: Mild traumatic brain injury (mTBI) is a health problem with an increasing incidence in many developed countries. The standard for examining mTBI is a CT scan, but it is costly, is not always available in all hospitals, and carries a risk of radiation. Meanwhile, S100β is a protein component produced by central nervous system cells. This study aims to determine the presence of changes in S100β protein in adult patients with mTBI during treatment as an alternative to examination. Methods: This research is an analytic observational quantitative study with a cross-sectional study approach to investigate changes in S100β protein levels in blood serum using the ELISA method of mTBI patients in the first 3 h posttrauma (pretest) and treatment on day 1 (27 h posttrauma/posttest). The research sample consisted of 22 people. This research was conducted in the Surgery Section, Sub-Division of Neurosurgery, Dr. Moewardi Public Hospital, during September–December 2019. The data were then analyzed using a discrimination test (comparing t-test means) and a nonparametric test (Wilcoxon). Results: There was a significant difference in mean S100β change between the pretest and posttest treatments. The S100β examination results at posttest decreased to 0.0223 + 0.0029 μg/l or decreased S100β by 21.7% after treatment. Previously, it was known that the mean of S100β at pretest was 0.0285 + 0.0137 μg/l. Conclusion: There was a significant change in S100β protein levels at each examination time. Changes in S100β levels that occurred were in the form of decreased levels from 3 h to 27 h posttrauma. Thus, S100β protein can be used as a parameter to assess the clinical development of adult patients with mTBI. Moreover, none of the patients with an S100β value >0.1 μg/l was found to be the cutoff value set by SNC in adult patients with mTBI for head CT scan.

Role of S100β Glial Protein as a Serological Marker for Analysis of Acute Ischemic Stroke

Background: Stroke is a major cause of neurological disability, which can be often predicted with serological markers. Glial-derived S100β protein is a potential biomarker for cerebral ischemia and may be helpful in predicting the severity, outcome, and recovery of stroke. Aim: This study aimed to study the role of S100β glial protein as a serological marker in predicting the severity of acute ischemic stroke (AIS), outcome, and functional recovery after 1 month. Methods: A hospital-based prospective case control study included 43 consecutive patients, >18 years old, who were admitted with acute middle cerebral artery (MCA) territory infarcts within 72 h of onset of neurological deficits. Control group comprised of 43 age-matched asymptomatic volunteers. Independent t-test and chi square test were used to compare the means and evaluate the association between protein level and various parameters. P ≤ .05 was statistically significant. Results: S100β protein level in AIS patients was significantly higher compared to controls ( P < .05). Elevated serum S100β protein level was found to be associated with larger infarct volumes, higher National Institute Health Stroke Scale scores, and higher modified Rankin Scale scores at admission ( P < .05). Patients with higher S100β protein levels at admission had poor recovery at 1 month compared to patients having normal S100β protein levels. Conclusion: S100β protein levels at admission after an acute MCA territory infarct may be used as a reliable serological tool in predicting the severity, outcome, and functional recovery in stroke.

Modification of metabolic disorders in the pathogenesis of spontaneous preterm birth

Objective. To determine the levels of interleukins, neopterin, S100β protein in amniotic fluid and cord blood, show their role in the pathogenesis of preterm birth and perinatal injury of the central nervous system (CNS) in newborns. Patients and methods. The study included 77 women randomly selected by simple randomization. A single-center, singlestage, controlled, randomized trial was conducted, which included 77 women comprising two groups: the main group – 33 patients with spontaneous preterm birth (35–37 weeks) and the control group – 44 women with the physiological course of pregnancy and childbirth (38–40 weeks). All newborns were also examined. The levels of interleukins IL-33 and IL-4, as well as neopterin and S100β protein were determined in amniotic fluid and cord blood by a solid-phase enzyme-linked immunosorbent assay (ELISA). Results. It was found that the increased production of interleukins and neurospecific proteins under study have a negative effect on the body of the pregnant woman and the fetus, which leads to serious pregnancy complications such as premature birth and perinatal CNS injury. Conclusion. The identified patterns provide a basis for the development of schemes for predicting preterm birth, which will improve perinatal outcomes and the health status of newborns. Key words: S100β protein, interleukins, neopterin, amniotic fluid, spontaneous preterm birth

Investigating the Conformation of S100β Protein Under Physiological Parameters Using Computational Modeling: A Clue for Rational Drug Design

Background: Physiochemical factors such as temperature, pH and cofactors are well known parameters that confer conformational changes in a protein structure. With S100β protein being a metal binding brain-specific receptor for both extracellular and intracellular functions, a change in conformation due to the above-mentioned factors, can compromise their cellular functions and therefore result in several pathological conditions such as Alzheimer’s disease, Ischemic stroke, as well as Myocardial Infarction. Objective: The studies conducted sought to elucidate the effect of these physiological factors on the conformational dynamics of S100β protein using computational modeling approaches. Method: Temperature-dependent and protein-cofactor complexes molecular dynamics simulations were conducted by varying the temperature from 100 to 400K using GROMACS 5.0.3. Additionally, the conformational dynamics of the protein was studied by varying the pH at 5.0, 7.4 and 9.0 using Ambertools17. This was done by preparing the protein molecule, solvating and minimizing its energy level as well as heating it to the required temperature, equilibrating and simulating under desired conditions (NVT and NPT ensembles). Results: The results show that the protein misfolds as a function of increasing temperature with alpha helical content at 100K and 400K being 57.8% and 43.3%, respectively. However, the binding sites of the protein was not appreciably affected by temperature variations. The protein displayed high conformational instability in acidic medium (pH ~5.0). The binding sites of Ca2+, Mg2+ and Zn2+ were identified and each exhibited different groupings of the secondary structural elements (binding motifs). The secondary structure analysis revealed different conformational changes with the characteristic appearance of two beta hairpins in the presence of Zn2+and Mg2+. Conclusion: High temperatures, different cofactors and acidic pH confer conformational changes to the S100β structure and these results may inform the design of novel drugs against the protein.