Brain‐derived neurotrophic factor alleviates the oxidative stress induced by oxygen and glucose deprivation in an ex vivo brain slice model

Neuroprotection of Human Umbilical Cord-Derived Mesenchymal Stem Cells (hUC-MSCs) in Alleviating Ischemic Stroke-Induced Brain Injury by Regulating Inflammation and Oxidative Stress

Brain injury caused by stroke has a high rate of mortality and remains a major medical challenge worldwide. In recent years, there has been significant attention given to the use of human Umbilical cord-derived Mesenchymal Stem Cells (hUC-MSCs) for the treatment of stroke in different adult and neonate animal models of stroke. However, using hUC-MSCs by systemic administration to treat ischemic stroke has not been investigated sufficiently. In this study, we conducted various experiments to explore the neuroprotection of hUC-MSCs in rats. Our findings demonstrate that an intravenous injection of a high dose of hUC-MSCs at 2 × 10^7 cells/kg markedly ameliorated brain injury resulting from ischemic stroke. This improvement was observed one day after inducing transient middle cerebral artery occlusion (MCAO) and subsequent reperfusion in rats. Notably, the efficacy of this single administration of hUC-MSCs surpassed that of edaravone, even when the latter was used continuously over three days. Mechanistically, secretory factors derived from hUC-MSCs, such as HGF, BDNF, and TNFR1, ameliorated the levels of MDA and T-SOD to regulate oxidative stress. In particular, TNFR1 also improved the expression of NQO-1 and HO-1, important proteins associated with oxidative stress. More importantly, TNFR1 played a significant role in reducing inflammation by modulating IL-6 levels in the blood. Furthermore, TNFR1 was observed to influence the permeability of the blood-brain barrier (BBB) as demonstrated in the evan's blue experiment and protein expression of ZO-1. This study represented a breakthrough in traditional methods and provided a novel strategy for clinical medication and trials.

Relationship between plasma brain-derived neurotrophic factor levels and neurological disorders: An investigation using Mendelian randomisation

Background

Altered brain-derived neurotrophic factor (BDNF) concentrations have been detected in the central nervous system tissues and peripheral blood. These alterations are associated with a series of neurological disorders.

Objective

To investigate the potential causal relationships between genetically determined plasma BDNF levels and various neurological diseases using a two-sample Mendelian randomisation study.

Methods

We selected single nucleotide polymorphisms strongly related to plasma BDNF levels as instrumental variables. Within the Mendelian randomisation framework, we used summary-level statistics for exposure (plasma BDNF levels) and outcomes (neurological disorders).

Results

We observed suggestive evidence of a relation between higher plasma BDNF levels and less risk of nontraumatic intracranial haemorrhage (nITH) (odds ratio [OR] = 0.861, 95 % confidence interval [CI]: 0.774-0.958, P = 0.006, PFDR = 0.078), epilepsy (OR = 0.927, 95 % CI: 0.880-0.976, P = 0.004, PFDR = 0.078), focal epilepsy (OR = 0.928, 95 % CI: 0.874-0.986, P = 0.016, PFDR = 0.139), and non-lesional focal epilepsy (OR = 0.981, 95 % CI: 0.964-0.999, P = 0.041, PFDR = 0.267). Combined with the UK Biobank dataset, the association of plasma BDNF levels with nITH remained significant (OR = 0.88, 95 % CI: 0.81-0.96, P < 0.01). The combined analysis of three consortium datasets demonstrated a considerable impact of plasma BDNF on epilepsy (OR = 0.94, 95 % CI: 0.90-0.98, P < 0.01) and a suggestive impact on focal epilepsy (OR = 0.94, 95 % CI: 0.89-0.99, P = 0.02). However, there was no apparent correlation between plasma BDNF levels and other neurological disorders or related subtypes.

Conclusions

Our study supports a possible causal relationship between elevated plasma BDNF levels and a reduced risk of nITH, epilepsy, and focal epilepsy.

Age-related telomere attrition in the human putamen

Age is a major risk factor for neurodegenerative diseases. Shortening of leucocyte telomeres with advancing age, arguably a measure of "biological" age, is a known phenomenon and epidemiologically correlated with age-related disease. The main mechanism of telomere shortening is cell division, rendering telomere length in post-mitotic cells presumably stable. Longitudinal measurement of human brain telomere length is not feasible, and cross-sectional cortical brain samples so far indicated no attrition with age. Hence, age-related changes in telomere length in the brain and the association between telomere length and neurodegenerative diseases remain unknown. Here, we demonstrate that mean telomere length in the putamen, a part of the basal ganglia, physiologically shortens with age, like leukocyte telomeres. This was achieved by using matched brain and leukocyte-rich spleen samples from 98 post-mortem healthy human donors. Using spleen telomeres as a reference, we further found that mean telomere length was brain region-specific, as telomeres in the putamen were significantly shorter than in the cerebellum. Expression analyses of genes involved in telomere length regulation and oxidative phosphorylation revealed that both region- and age-dependent expression pattern corresponded with region-dependent telomere length dynamics. Collectively, our results indicate that mean telomere length in the human putamen physiologically shortens with advancing age and that both local and temporal gene expression dynamics correlate with this, pointing at a potential mechanism for the selective, age-related vulnerability of the nigro-striatal network.

Effectiveness of eye movement exercise and diaphragmatic breathing with jogging in reducing migraine symptoms: A preliminary, randomized comparison trial

BACKGROUND

Migraine is a multifactorial headache disorder. Maladaptive functional networks or altered circuit-related connectivity in the brain with migraine appear to perturb the effects of usual treatments.

OBJECTIVES

In the present preliminary trial, we aim to study the effectiveness of performing pieces of body-mind, cognitive, or network reconstruction-based training (i.e., eye movement exercise plus jogging; EME+J and diaphragmatic breathing plus jogging; DB+J) in decreasing migraine symptoms.

METHODS

We used a three-arm, triple-blind, non-inferiority randomized comparison design with pre-test, post-test, and follow-up measurements to assess the effectiveness of EME+J and DB+J in the brain with migraine. Participants were randomly assigned to one of the study groups to perform either 12 consecutive weeks of EME+J (n = 22), DB+J (n = 19), or receiving, treatment as usual, TAU (n = 22).

RESULTS

The primary outcome statistical analysis through a linear mixed model showed a significant decrease in the frequency (p = .0001), duration (p = .003), and intensity (p = .007) of migraine attacks among the interventions and measurement times. The pairwise comparisons of simple effects showed that EME+J and DB+J effectively reduced migraine symptoms at the post-test and follow-up (p < .05). Cochran's tests showed that interventions decreased the number of menses-related migraine attacks. EME+J and DB+J effectively decreased over-the-counter (OTC) drug use, refreshed wake-up mode, and improved sleep and water drinking patterns. These are the secondary outcomes that Cochran's tests showed in the interventional groups after the interventions and at 12 months of follow-up.

CONCLUSION

EME+J or DB+J can be an effective and safe method with no adverse effects to decrease the symptoms of migraine attacks. Moreover, a reduction in the frequency of menstrual cycle-related attacks, OTC drug use, and improved quality of sleep and drinking water were the secondary outcomes of the post-test and a 12-month follow-up.

Astrocyte Reaction to Catechol-Induced Cytotoxicity Relies on the Contact with Microglia Before Isolation

Astrocytes preserve the brain microenvironment homeostasis in order to protect other brain cells, mainly neurons, against damages. Glial cells have specific functions that are important in the context of neuronal survival in different models of central nervous system (CNS) diseases. Microglia are among these cells, secreting several molecules that can modulate astrocyte functions. Although 1,2-dihydroxybenzene (catechol) is a neurotoxic monoaromatic compound of exogenous origin, several endogenous molecules also present the catechol group. This study compared two methods to obtain astrocyte-enriched cultures from newborn Wistar rats of both sexes. In the first technique (P1), microglial cells began to be removed early 48 h after primary mixed glial cultures were plated. In the second one (P2), microglial cells were late removed 7 to 10 days after plating. Both cultures were exposed to catechol for 72 h. Catechol was more cytotoxic to P1 cultures than to P2, decreasing cellularity and changing the cell morphology. Microglial-conditioned medium (MCM) protected P1 cultures and inhibited the catechol autoxidation. P2 cultures, as well as P1 in the presence of 20% MCM, presented long, dense, and fibrillary processes positive for glial fibrillary acidic protein, which retracted the cytoplasm when exposed to catechol. The Ngf and Il1beta transcription increased in P1, meanwhile astrocytes expressed more Il10 in P2. Catechol decreased Bdnf and Il10 in P2 cultures, and it decreased the expression of Il1beta in both conditions. A prolonged contact with microglia before isolation of astrocyte-enriched cultures modifies astrocyte functions and morphology, protecting these cells against catechol-induced cytotoxicity.

Human Amnion-Derived Mesenchymal Stromal/Stem Cells Pre-Conditioning Inhibits Inflammation and Apoptosis of Immune and Parenchymal Cells in an In Vitro Model of Liver Ischemia/Reperfusion

Ischemia/reperfusion injury (IRI) represents one of the leading causes of primary non-function acute liver transplantation failure. IRI, generated by an interruption of organ blood flow and the subsequent restoration upon transplant, i.e., reperfusion, generates the activation of an inflammatory cascade from the resident Kupffer cells, leading first to neutrophils recruitment and second to apoptosis of the parenchyma. Recently, human mesenchymal stromal/stem cells (hMSCs) and derivatives have been implemented for reducing the damage induced by IRI. Interestingly, sparse data in the literature have described the use of human amnion-derived MSCs (hAMSCs) and, more importantly, no evidence regarding hMSCs priming on liver IRI have been described yet. Thus, our study focused on the definition of an in vitro model of liver IRI to test the effect of primed hAMSCs to reduce IRI damage on immune and hepatic cells. We found that the IFNγ pre-treatment and 3D culture of hAMSCs strongly reduced inflammation induced by M1-differentiated macrophages. Furthermore, primed hAMSCs significantly inhibited parenchymal apoptosis at early timepoints of reperfusion by blocking the activation of caspase 3/7. All together, these data demonstrate that hAMSCs priming significantly overcomes IRI effects in vitro by engaging the possibility of defining the molecular pathways involved in this process.

T1AM-TAAR1 signalling protects against OGD-induced synaptic dysfunction in the entorhinal cortex

Abnormalities in thyroid hormones (TH) availability and/or metabolism have been hypothesized to contribute to Alzheimer's disease (AD) and to be a risk factor for stroke. Recently, 3-iodothyronamine (T₁AM), an endogenous amine putatively derived from TH metabolism, gained interest for its ability to promote learning and memory in the mouse. Moreover, T₁AM has been demonstrated to rescue the β-Amyloid dependent LTP impairment in the entorhinal cortex (EC), a brain area crucially involved in learning and memory and early affected during AD. In the present work, we have investigated the effect of T₁AM on ischemia-induced EC synaptic dysfunction. In EC brain slices exposed to oxygen-glucose deprivation (OGD), we demonstrated that the acute perfusion of T₁AM (5 μM) was capable of preventing ischemia-induced synaptic depression and that this protective effect was mediated by the trace amine-associated receptor 1 (TAAR1). Moreover, we demonstrated that activation of the BDNF-TrkB signalling is required for T₁AM action during ischemia. The protective effect of T₁AM was more evident when using EC slices from transgenic mutant human APP (mhAPP mice) that are more vulnerable to the effect of OGD. Our results confirm that the TH derivative T₁AM can rescue synaptic function after transient ischemia, an effect that was also observed in a Aβ-enriched environment.

Modulatory Effect of Myokines on Reactive Oxygen Species in Ischemia/Reperfusion

There is a growing body of evidence showing the importance of physical activity against acute ischemic events in various organs. Ischemia/reperfusion injury (I/R) is characterized by tissue damage as a result of restriction and subsequent restoration of blood supply to an organ. Oxidative stress due to increased reactive oxygen species formation and/or insufficient antioxidant defense is considered to play an important role in I/R. Physical activity not only decreases the general risk factors for ischemia but also confers direct anti-ischemic protection via myokine production. Myokines are skeletal muscle-derived cytokines, representing multifunctional communication channels between the contracting skeletal muscle and other organs through an endocrine manner. In this review, we discuss the most prominent members of the myokines (i.e., brain-derived neurotrophic factor (BDNF), cathepsin B, decorin, fibroblast growth factors-2 and -21, follistatin, follistatin-like, insulin-like growth factor-1; interleukin-6, interleukin-7, interleukin-15, irisin, leukemia inhibitory factor, meteorin-like, myonectin, musclin, myostatin, and osteoglycin) with a particular interest in their potential influence on reactive oxygen and nitrogen species formation or antioxidant capacity. A better understanding of the mechanism of action of myokines and particularly their participation in the regulation of oxidative stress may widen their possible therapeutic use and, thereby, may support the fight against I/R.

Characterization of an eutherian gene cluster generated after transposon domestication identifies Bex3 as relevant for advanced neurological functions

BACKGROUND

One of the most unusual sources of phylogenetically restricted genes is the molecular domestication of transposable elements into a host genome as functional genes. Although these kinds of events are sometimes at the core of key macroevolutionary changes, their origin and organismal function are generally poorly understood.

RESULTS

Here, we identify several previously unreported transposable element domestication events in the human and mouse genomes. Among them, we find a remarkable molecular domestication that gave rise to a multigenic family in placental mammals, the Bex/Tceal gene cluster. These genes, which act as hub proteins within diverse signaling pathways, have been associated with neurological features of human patients carrying genomic microdeletions in chromosome X. The Bex/Tceal genes display neural-enriched patterns and are differentially expressed in human neurological disorders, such as autism and schizophrenia. Two different murine alleles of the cluster member Bex3 display morphological and physiopathological brain modifications, such as reduced interneuron number and hippocampal electrophysiological imbalance, alterations that translate into distinct behavioral phenotypes.

CONCLUSIONS

We provide an in-depth understanding of the emergence of a gene cluster that originated by transposon domestication and gene duplication at the origin of placental mammals, an evolutionary process that transformed a non-functional transposon sequence into novel components of the eutherian genome. These genes were integrated into existing signaling pathways involved in the development, maintenance, and function of the CNS in eutherians. At least one of its members, Bex3, is relevant for higher brain functions in placental mammals and may be involved in human neurological disorders.

Over-Expression of TRPC6 via CRISPR Based Synergistic Activation Mediator in BMSCs Ameliorates Brain Injury in a Rat Model of Cerebral Ischemia/Reperfusion

Stroke is a major life-threatening and disabling disease with a restricted therapeutic approach. Bone marrow stromal cells (BMSCs) possess proliferative ability and a multi-directional differentiation potential, and secrete a range of trophic/growth factors that can protect neurons after cerebral ischemia/reperfusion. Transient receptor potential canonical (TRPC) is a family of non-selective channels permeable to Ca2+, with several functions including neuronal survival. Over-expression of TRPC6, a subtype of the TRPC family, was shown to protect neurons against cerebral ischemia/reperfusion injury. However, it remains unclear whether over-expression of TRPC6 in BMSCs can further reduce brain injury after ischemia/reperfusion. In the present study, we report that over-expression of TRPC6 via a CRISPR-based synergistic activation mediator in BMSCs provided a greater reduction of brain injury in a rat model of ischemia/reperfusion. Further, the improved neurofunctional outcomes were associated with increased TRPC6 and brain derived neurotrophic factor expression levels. Overall, these data suggest that TRPC6 over-expressing BMSCs may be a promising therapeutic agent for ischemic stroke.