Preconditioning in hypoxic-ischemic neonate mice triggers Na+-Ca2+ exchanger-dependent neurogenesis

Preconditioning and Posttreatment Strategies in Neonatal Hypoxic-Ischemic Encephalopathy: Recent Advances and Clinical Challenges

Neonatal hypoxic-ischemic encephalopathy (HIE) is a severe neurological disorder caused by impaired cerebral blood flow and brain hypoxia, resulting in high morbidity and mortality rates. While therapeutic hypothermia remains the standard treatment and has been shown to reduce mortality to some extent, its therapeutic efficacy is limited, and it applies only to a select group of neonates who meet stringent inclusion criteria. Advances in our understanding of the pathophysiology of HIE have led to the identification of several promising neuroprotective strategies designed to mitigate or prevent the neurological damage induced by hypoxia-ischemia. Among these, preconditioning has emerged as a potent neuroprotective approach, enhancing cellular resilience to subsequent injury and potentially reducing treatment complexity and healthcare costs. Preconditioning/pretreatment and posttreatment offer significant promise in attenuating the neurological damage associated with HIE. Thus, exploring early intervention strategies for neonatal HIE, focusing on the comparative mechanisms and therapeutic targets of preconditioning and postconditioning, is critical to developing more effective treatment modalities. This review summarizes the current understanding of the pathophysiological mechanisms underlying neonatal HIE and its prevention and treatment strategies, providing new perspectives and a theoretical foundation for future neuroprotective interventions.

Investigating Molecular Mechanisms in Ischemic Preconditioning-Induced Resiliency to Severe Acute Global Cerebral Ischemia Using a Mouse Model of Chronic Cerebral Hypoperfusion

Cerebral ischemic preconditioning offers a promising strategy to enhance resilience to severe ischemic insults. Unilateral common carotid artery occlusion (UCCAo) is a valuable model to simulate chronic cerebral hypoperfusion (CCH). This study explored UCCAo-induced CCH as a preconditioning stimulus to induce ischemic tolerance against transient global cerebral ischemia (tGCI) induced by bilateral common carotid artery occlusion (BCCAo) in both male and female mice. We evaluated the effects of CCH preconditioning on neuroprotection and recovery through behavioral, histopathological, and molecular analyses. Laser Doppler Imaging (LDI) confirmed significant cerebral hypoperfusion post-UCCAo. Preconditioning reduced mortality rates at days 1 and 7 post-surgery as compared to BCCAo, suggesting its neuroprotective potential. Neurodeficit scoring demonstrated significant protection in preconditioned animals with recovery aligning closer to sham controls. Behavioral assays revealed improved motor and cognitive outcomes in preconditioned groups, with sex-specific differences evident in recovery dynamics. Molecular analyses indicated reduced reactive astrocyte (GFAP) and microglial (IBA1) activation in preconditioned animals, reflecting controlled glial responses. Sex-dependent variations in markers of hypoxia (Hif1a), autophagy (Becn1), and neurogenesis (Sox2) highlighted neuroadaptive and cellular influences on ischemic resilience. Preconditioning enhanced synaptic plasticity by upregulating PSD-95, synaptophysin and BDNF levels. In addition, preconditioning increased VEGF expression in blood serum reflecting vascular remodeling and neuroprotective angiogenesis. This study positions UCCAo-induced CCH as a reliable model for exploring ischemic tolerance mechanisms to advance therapeutic strategies for mitigating the effects of ischemic stroke.

Nanoparticles encapsulating phosphatidylinositol derivatives promote neuroprotection and functional improvement in preclinical models of ALS via a long-lasting activation of TRPML1 lysosomal channel

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease currently incurable, in which motor neuron degeneration leads to voluntary skeletal muscle atrophy. Molecularly, ALS is characterized by protein aggregation, synaptic and organellar dysfunction, and Ca2+ dyshomeostasis. Of interest, autophagy dysfunction is emerging as one of the main putative targets of ALS therapy. A tune regulation of this cleansing process is affordable by a proper stimulation of TRPML1, one of the main lysosomal channels. However, TRPML1 activation by PI(3,5)P2 has low open probability to remain in an active conformation. To overcome this drawback we developed a lipid-based formulation of PI(3,5)P2 whose putative therapeutic potential has been tested in in vitro and in vivo ALS models. Pharmacodynamic properties of PI(3,5)P2 lipid-based formulations (F1 and F2) on TRPML1 activity have been characterized by means of patch-clamp electrophysiology and Fura-2AM video-imaging in motor neuronal cells. Once selected for the ability to stabilize TRPML1 activity, the most effective preparation F1 was studied in vivo to measure neuromuscular function and survival of SOD1G93A ALS mice, thereby establishing its therapeutic profile. F1, but not PI(3,5)P2 alone, stabilized the open state of the lysosomal channel TRPML1 and increased the persistence of intracellular calcium concentration ([Ca2+]i). Then, F1 was effective in delaying motor neuron loss, improving innervated endplants and muscle performance in SOD1G93A mice, extending overall lifespan by an average of 10 days. Of note F1 prevented gliosis and autophagy dysfunction in ALS mice by restoring PI(3,5)P2 level. Our novel self-assembling lipidic formulation for PI(3,5)P2 delivery exerts a neuroprotective effect in preclinical models of ALS mainly regulating dysfunctional autophagy through TRPML1 activity stabilization.

Novel insight into the role of A-kinase anchoring proteins (AKAPs) in ischemic stroke and therapeutic potentials

Ischemic stroke, a devastating disease associated with high mortality and disability worldwide, has emerged as an urgent public health issue. A-kinase anchoring proteins (AKAPs) are a group of signal-organizing molecules that compartmentalize and anchor a wide range of receptors and effector proteins and have a major role in stabilizing mitochondrial function and promoting neurodevelopmental development in the central nervous system (CNS). Growing evidence suggests that dysregulation of AKAPs expression and activity is closely associated with oxidative stress, ion disorder, mitochondrial dysfunction, and blood-brain barrier (BBB) impairment in ischemic stroke. However, the underlying mechanisms remain inadequately understood. This review provides a comprehensive overview of the composition and structure of A-kinase anchoring protein (AKAP) family members, emphasizing their physiological functions in the CNS. We explored in depth the molecular and cellular mechanisms of AKAP complexes in the pathological progression and risk factors of ischemic stroke, including hypertension, hyperglycemia, lipid metabolism disorders, and atrial fibrillation. Herein, we highlight the potential of AKAP complexes as a pharmacological target against ischemic stroke in the hope of inspiring translational research and innovative clinical approaches.

Anti-miRNA103/107 encapsulated in transferrin-conjugated lipid nanoparticles crosses blood-brain barrier and reduces brain ischemic damage

MicroRNA (miRNA), by post-transcriptionally regulating the expression of genes involved in stroke response, represents important effectors in stroke pathophysiology. Recently, the 103/107 miRNA family emerged as a possible therapeutic target in stroke, as it controls the expression of sodium calcium exchanger 1, a plasma membrane transporter that plays a fundamental role in stroke pathophysiology. Although the neuroprotective properties of this and other miRNAs are promising, several pharmacokinetic drawbacks remain to be faced for the development of a translatable therapy based on small RNAs in CNS diseases. In the present study, to overcome these limitations, the anti-miRNA103/107 was encapsulated in specific preparations of lipid nanoparticles (LNPs), and their effectiveness was evaluated both in an in vitro model of hypoxia represented by primary neuronal cortical cultures exposed to oxygen and glucose deprivation followed by reoxygenation, and in an in vivo model of stroke obtained in rats exposed to transient occlusion of the middle cerebral artery. The results of the present study demonstrated that the encapsulation of anti-miRNA103/107 in transferrin-conjugated PEG-stabilized LNPs allowed the blood-brain barrier crossing and significantly reduced brain ischemic damage. The present achievements pave the way for the exploitation of a systemic intravenous miRNA delivery strategy in stroke therapy.

Research hotspots and frontiers of preconditioning in cerebral ischemia: A bibliometric analysis

Background

Preconditioning is a promising strategy against ischemic brain injury, and numerous studies in vitro and in vivo have demonstrated its neuroprotective effects. However, at present there is no bibliometric analysis of preconditioning in cerebral ischemia. Therefore, a comprehensive overview of the current status, hot spots, and emerging trends in this research field is necessary.

Materials and methods

Studies on preconditioning in cerebral ischemia from January 1999-December 2022 were retrieved from the Web of Science Core Collection (WOSCC) database. CiteSpace was used for data mining and visual analysis.

Results

A total of 1738 papers on preconditioning in cerebral ischemia were included in the study. The annual publications showed an upwards and then downwards trend but currently remain high in terms of annual publications. The US was the leading country, followed by China, the most active country in recent years. Capital Medical University published the largest number of articles. Perez-Pinzon, Miguel A contributed the most publications, while KITAGAWA K was the most cited author. The focus of the study covered three areas: (1) relevant diseases and experimental models, (2) types of preconditioning and stimuli, and (3) mechanisms of ischemic tolerance. Remote ischemic preconditioning, preconditioning of mesenchymal stem cells (MSCs), and inflammation are the frontiers of research in this field.

Conclusion

Our study provides a visual and scientific overview of research on preconditioning in cerebral ischemia, providing valuable information and new directions for researchers.

SMN deficiency perturbs monoamine neurotransmitter metabolism in spinal muscular atrophy

Beyond motor neuron degeneration, homozygous mutations in the survival motor neuron 1 (SMN1) gene cause multiorgan and metabolic defects in patients with spinal muscular atrophy (SMA). However, the precise biochemical features of these alterations and the age of onset in the brain and peripheral organs remain unclear. Using untargeted NMR-based metabolomics in SMA mice, we identify cerebral and hepatic abnormalities related to energy homeostasis pathways and amino acid metabolism, emerging already at postnatal day 3 (P3) in the liver. Through HPLC, we find that SMN deficiency induces a drop in cerebral norepinephrine levels in overt symptomatic SMA mice at P11, affecting the mRNA and protein expression of key genes regulating monoamine metabolism, including aromatic L-amino acid decarboxylase (AADC), dopamine beta-hydroxylase (DβH) and monoamine oxidase A (MAO-A). In support of the translational value of our preclinical observations, we also discovered that SMN upregulation increases cerebrospinal fluid norepinephrine concentration in Nusinersen-treated SMA1 patients. Our findings highlight a previously unrecognized harmful influence of low SMN levels on the expression of critical enzymes involved in monoamine metabolism, suggesting that SMN-inducing therapies may modulate catecholamine neurotransmission. These results may also be relevant for setting therapeutic approaches to counteract peripheral metabolic defects in SMA.