Quantitative studies of caspase-3 catalyzed αII-spectrin breakdown

A Preliminary Study on Investigation of Blood-Brain Barrier Damage Markers in Patients with Alcohol Use Disorder Before and After Therapy

AIM

The use of alcohol affects the central nervous system and plays important roles in various neurological disorders through neurotoxicity resulting from blood-brain barrier (BBB) permeability. The BBB is regulated by tight junction proteins interacting closely with endothelial cells. This study evaluated the serum levels of proteins and spectrin degradation products associated with BBB damage in patients with alcohol use disorder.

METHODS

This preliminary case-control study was conducted with 30 healthy volunteers and 26 alcohol use disorder patients. The serum levels of spectrin breakdown product 145 (SBDP145), spectrin breakdown product 150 (SBDP150), ubiquitin carboxy-terminal hydrolase L1 (UCHL1), ubiquitin ligase cullin-3 (ULC), occludin and claudin were measured with enzyme-linked immunosorbent assay.

RESULTS

There was no significant difference between the levels of SBDP145, SBDP150, UCHL1, ULC, occludin and claudin before and after treatment in patients with alcohol use disorder. SBDP150 levels were significantly lower in patients than controls (P < 0.001). The area under the curve was 0.841 (0.733-0.949) with the 95% confidence interval for SPDP150.

CONCLUSION

A decrease of the serum SBDP150 levels appears to be associated with alcohol use disorder. Future studies might clarify whether diminished serum SBDP150 levels are associated with BBB damage in patients with alcohol use disorder.

Mechanical behavior of actin and spectrin subjected to high strain rate: A molecular dynamics simulation study

Recent nanoscopy and super-resolution microscopy studies have substantiated the structural contribution of periodic actin-spectrin lattice to the axonal cytoskeleton of neuron. However, sufficient mechanical insight is not present for spectrin and actin-spectrin network, especially in high strain rate scenario. To quantify the mechanical behavior of actin-spectrin cytoskeleton in such conditions, this study determines individual stretching characteristics of actin and spectrin at high strain rate by molecular dynamics (MD) simulation. The actin-spectrin separation criteria are also determined. It is found that both actin and spectrin have high stiffness when susceptible to high strain rate and show strong dependence on applied strain rate. The stretching stiffness of actin and forced unfolding mechanism of spectrin are in harmony with the current literature. Actin-spectrin model provides novel insight into their interaction and separation stretch. It is shown that the region vulnerable to failure is the actin-spectrin interface at lower strain rate, while it is the inter-repeat region of spectrin at higher strain rate.

Clinical significance of detecting serum melatonin and SBDPs in brain injury in preterm infants

BACKGROUND

To investigate the clinical values of serum melatonin and αII spectrin cleavage products (SBDPs) in assessing the severity of brain injury in preterm infants.

METHODS

Sixty-four premature infants in total were selected and classified into the brain injury group (BI, n = 30) and the non-brain injury group (CON, n = 34) according to cranial imaging examination. The serum melatonin and SBDPs were detected by ELISA. All the preterm infants were received NBNA testing at 40 weeks of corrected gestational age.

RESULTS

The levels of melatonin and SBDPs in the BI group were significantly higher than the CON group (p < 0.05) and the levels in the infants with severe brain injury were significantly higher than those with mild brain injury (p < 0.05), as well as exhibiting a negative correlation with the NBNA score at 40 weeks of corrected gestational age (p < 0.05).

CONCLUSIONS

Detecting melatonin and SBDPs has clinical value in diagnosing and assessing the severity of brain injury in preterm infants.

Prospective clinical biomarkers of caspase-mediated apoptosis associated with neuronal and neurovascular damage following stroke and other severe brain injuries: Implications for chronic neurodegeneration

Acute brain injuries, including ischemic and hemorrhagic stroke, as well as traumatic brain injury (TBI), are major worldwide health concerns with very limited options for effective diagnosis and treatment. Stroke and TBI pose an increased risk for the development of chronic neurodegenerative diseases, notably chronic traumatic encephalopathy, Alzheimer's disease, and Parkinson's disease. The existence of premorbid neurodegenerative diseases can exacerbate the severity and prognosis of acute brain injuries. Apoptosis involving caspase-3 is one of the most common mechanisms involved in the etiopathology of both acute and chronic neurological and neurodegenerative diseases, suggesting a relationship between these disorders. Over the past two decades, several clinical biomarkers of apoptosis have been identified in cerebrospinal fluid and peripheral blood following ischemic stroke, intracerebral and subarachnoid hemorrhage, and TBI. These biomarkers include selected caspases, notably caspase-3 and its specific cleavage products such as caspase-cleaved cytokeratin-18, caspase-cleaved tau, and a caspase-specific 120 kDa αII-spectrin breakdown product. The levels of these biomarkers might be a valuable tool for the identification of pathological pathways such as apoptosis and inflammation involved in injury progression, assessment of injury severity, and prediction of clinical outcomes. This review focuses on clinical studies involving biomarkers of caspase-3-mediated pathways, following stroke and TBI. The review further examines their prospective diagnostic utility, as well as clinical utility for improved personalized treatment of stroke and TBI patients and the development of prophylactic treatment chronic neurodegenerative disease.

SBDPs and Tau proteins for diagnosis and hypothermia therapy in neonatal hypoxic ischemic encephalopathy

The use of spectrin breakdown products (SBDPs) and Tau protein levels for diagnosis and a mild hypothermia therapy for treatment of neonatal hypoxic-ischemic encephalopathy (HIE) was evaluated. One hundred and fifty infants, with HIE within 12 h after birth, participated in the study. There were 30 newborns with mild symptoms, 60 with moderate symptoms, 60 with severe symptoms, and 30 in a control group. Regular therapy was used for the control and the mild HIE groups, and also for 30 cases in the group with moderate symptoms and for 30 in the group with severe symptoms. For the remaining infants, with moderate and severe symptoms, mild hypothermia therapy was used instead. A sandwich ELISA measured plasma concentrations of SBDPs and Tau proteins, at different time-points. For clinical follow-up, the neonatal behavioral neurological assessment (NBNA) assay and the Gesell development scale were performed at different time-points. The levels of SBDP and Tau proteins increased with the exacerbation of HIE, and decreased with the prolongation of therapy with statistically significant differences amongst groups. After treatment, the levels of SBDP and Tau proteins in groups with moderate and severe symptoms treated with mild hypothermia therapy were significantly lower than those of the groups treated with regular therapy. NBNA scores and the developmental quotient (DQ) were both worse with the increase in severity of HIE, however, the scores of groups with moderate and severe symptoms treated with mild hypothermia therapy were significantly better than those of groups treated with regular therapy (P<0.05). A gradual improvement of DQ was seen in the process of therapy in each group (P<0.05). According to a receiver operating characteristic (ROC) curve analysis, at a critical plasma concentration of SBDPs of 1.58 ng/ml, the sensitivity and specificity for HIE diagnosis was 84.6 and 87.5%, respectively. The ROC analysis for Tau protein yielded a sensitivity and specificity of 79.5 and 96.9%, respectively, at a critical plasma concentration of 4.76 pg/ml. Given our results, SBDPs and Tau proteins are very useful for the early diagnosis of HIE. Early application of mild hypothermia therapy for the treatment of HIE can greatly improve the function of neural development. These findings should greatly improve the evaluation and treatment approaches for HIE.

An Efficient and Economical Assay to Screen for Triclosan Binding to FabI

Triclosan is an effective inhibitor for enoyl acyl carrier protein reductase (ENR) in fatty acid biosynthesis. Triclosan-resistant mutants of ENR have emerged. Thus, it is important to detect these triclosan-resistant mutations in ENR. Generally, enzyme activity assays on the mutants are used to determine the effect of triclosan on ENR activity. Since the substrates are linked to acyl carrier protein (ACP), the assays are challenging due to the need to prepare the ACP and link it to the substrates. Non-ACP-linked (coenzyme A [CoA]-linked) substrates can be used in some ENR, but not in all. Consequently, screening for triclosan-resistant mutants is also challenging. We have developed a simple thermal shift assay, which does not use ACP-linked substrates, to determine the binding ability of triclosan to the ENR active site, and thus it can be used for screening for triclosan-resistant mutants. Staphylococcus aureus FabI enzyme and its mutants were used to demonstrate the binding ability of triclosan with NADP(+) to FabI. The direct correlation between the binding ability and enzyme activity was demonstrated with Francisella tularensis FabI. This method may also be applied to select effective triclosan analogues that inhibit ENR activity.