Wnt and lithium: a common destiny in the therapy of nervous system pathologies?

Lithium response in bipolar disorder: Epigenome-wide DNA methylation signatures and epigenetic aging

Lithium (Li) is the first-line treatment for bipolar disorder (BD) even though only 30 % of BD patients are considered excellent responders. The mechanisms by which Li exerts its action are not clearly understood, but it has been suggested that specific epigenetic mechanisms, such as methylation processes, may play a role. In this regard, DNA methylation patterns can be used to estimate epigenetic age (EpiAge), which is accelerated in BD patients and reversed by Li treatment. Our first aim was to compare the DNA methylation profile in peripheral blood between BD patients categorized as excellent responders to Li (Ex-Rp) and non-responders (N-Rp). Secondly, EpiAge was estimated to detect differential age acceleration between the two groups. A total of 130 differentially methylated positions (DMPs) and 16 differentially methylated regions (DMRs) between Ex-Rp (n = 26) and N-Rp (n = 37) were identified (FDR adjusted p-value < 0.05). We found 122 genes mapping the DMPs and DMRs, nine of which (HOXB6, HOXB3, HOXB-AS3, TENM2, CACNA1B, ANK3, EEF2K, CYP1A1, and SORCS2) had previously been linked to Li response. We found genes related to the GSK3β pathway to be highly represented. Using FUMA, we found enrichment in Gene Ontology Cell Component for the synapse. Gene network analysis highlighted functions related to the cell cycle, nervous system development and function, and gene expression. No significant differences in age acceleration were found between Ex-Rp and N-Rp for any of the epigenetic clocks analysed. Our findings indicate that a specific methylation pattern could determine the response to Li in BD patients. We also found that a significant portion of the differentially methylated genes are closely associated with the GSK3β pathway, reinforcing the role of this system in Li response. Future longitudinal studies with larger samples will help to elucidate the epigenetic mechanisms underlying Li response.

Neural stem/progenitor cells from olfactory neuroepithelium collected by nasal brushing as a cell model reflecting molecular and cellular dysfunctions in schizophrenia

OBJECTIVES

Neural stem/progenitor cells derived from olfactory neuroepithelium (hereafter olfactory neural stem/progenitor cells, ONSPCs) are emerging as a potential tool in the exploration of psychiatric disorders. The present study intended to assess whether ONSPCs could help discern individuals with schizophrenia (SZ) from non-schizophrenic (NS) subjects by exploring specific cellular and molecular features.

METHODS

ONSPCs were collected from 19 in-patients diagnosed with SZ and 31 NS individuals and propagated in basal medium. Mitochondrial ATP production, expression of β-catenin and cell proliferation, which are described to be altered in SZ, were examined in freshly isolated or newly thawed ONSPCs after a few culture passages.

RESULTS

SZ-ONSPCs exhibited a lower mitochondrial ATP production and insensitivity to agents capable of positively or negatively affecting β-catenin expression with respect to NS-ONSPCs. As to proliferation, it declined in SZ-ONSPCs as the number of culture passages increased compared to a steady level of growth shown by NS-ONSPCs.

CONCLUSIONS

The ease and safety of sample collection as well as the differences observed between NS- and SZ-ONSPCs, may lay the groundwork for a new approach to obtain biological material from a large number of living individuals and gain a better understanding of the mechanisms underlying SZ pathophysiology.

A computational biology approach to identify potential protein biomarkers and drug targets for sporadic amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease caused by the loss of upper and lower motor neurons. The sporadic ALS (sALS) is a multigenic disorder and the complex mechanisms underlying its onset are still not fully delineated. Despite the recent scientific advancements, certain aspects of ALS pathogenic targets need to be yet clarified. The aim of the presented study is to identify potential genetic biomarkers and drug targets for sALS, by analysing gene expression profiles, presented in the publicly available GSE68605 dataset, of motor neurons cells obtained from sALS patients. We used different computational approaches including differential expression analysis, protein network mapping, candidate protein biomarker (CPB) identification, elucidation of the role of functional modules, and molecular docking analysis. The resultant top ten up- and downregulated genes were further used to construct protein-protein interaction network (PPIN). The PPIN analysis resulted in identifying four CPBs (namely RIOK2, AKT1, CTNNB1, and TNF) that commonly overlapped with one another in network parameters (degree, bottleneck and maximum neighbourhood component). The RIOK2 protein emerged as a potential mediator of top five functional modules that are associated with RNA binding, lipoprotein particle receptor binding in pre-ribosome, and interferon, cytokine-mediated signaling pathway. Furthermore, molecular docking analysis revealed that cyclosporine exhibited the highest binding affinity (-8.6 kJ/mol) with RIOK2, and surpassed the FDA-approved ALS drugs, such as riluzole and edaravone. This suggested that cyclosporine may serve as a promising candidate for targeting RIOK2 downregulation observed in sALS patients. In order to validate our computational results, it is suggested that in vitro and in vivo studies may be conducted in future to provide a more detailed understanding of ALS diagnosis, prognosis, and therapeutic intervention.

Lithium treatment mitigates the diabetogenic effects of chronic cortico-therapy

BACKGROUND AND PURPOSE

Glucocorticoids (GCs) are the main treatment for autoimmune and inflammatory disorders and are also used as immunosuppressive therapy for patients with organ transplantation. However, these treatments have several side effects, including metabolic disorders. Indeed, cortico-therapy may induce insulin resistance, glucose intolerance, disrupted insulin and glucagon secretion, excessive gluconeogenesis, leading to diabetes in susceptible individuals. Recently, lithium has been shown to alleviate deleterious effects of GCs in various diseased conditions.

EXPERIMENTAL APPROACH

In this study, using two rat models of GC-induced metabolic disorders, we investigated the effects of Lithium Chloride (LiCl) in the mitigation of deleterious effects of GCs. Rats were treated either with corticosterone or dexamethasone, and with or without LiCl. Animals were then assessed for glucose tolerance, insulin sensitivity, in vivo and ex vivo glucose-induced insulin secretion and hepatic gluconeogenesis.

KEY RESULTS

We showed that in rats chronically treated with corticosterone, lithium treatment markedly reduced insulin resistance. In addition, in rats treated with dexamethasone, lithium administration improved glucose tolerance, associated with enhanced insulin secretion in vivo. Moreover, liver gluconeogenesis was reduced upon LiCl treatment. The improvement of insulin secretion in vivo appeared to be due to an indirect regulation of β cell function, since the ex vivo assessment of insulin secretion and β cell mass in islets from animals treated with LiCl revealed no difference compared to untreated animals.

CONCLUSION AND IMPLICATIONS

Collectively, our data provide evidences for the beneficial effects of lithium to mitigate the adverse metabolic effects of chronic cortico-therapy.

Methylome-wide association study of different responses to risperidone in schizophrenia

Background: Accumulating evidence shows that DNA methylation plays a role in antipsychotic response. However, the mechanisms by which DNA methylation changes are associated with antipsychotic responses remain largely unknown. Methods: We performed a methylome-wide association study (MWAS) to evaluate the association between DNA methylation and the response to risperidone in schizophrenia. Genomic DNA methylation patterns were assessed using the Agilent Human DNA Methylation Microarray. Results: We identified numerous differentially methylated positions (DMPs) and regions (DMRs) associated with antipsychotic response. CYP46A1, SPATS2, and ATP6V1E1 had the most significant DMPs, with p values of 2.50 × 10^-6, 3.53 × 10^-6, and 5.71 × 10^-6, respectively. The top-ranked DMR was located on chromosome 7, corresponding to the PTPRN2 gene with a Šidák-corrected p-value of 9.04 × 10^-13. Additionally, a significant enrichment of synaptic function and neurotransmitters was found in the differentially methylated genes after gene ontology and pathway analysis. Conclusion: The identified DMP- and DMR-overlapping genes associated with antipsychotic response are related to synaptic function and neurotransmitters. These findings may improve understanding of the mechanisms underlying antipsychotic response and guide the choice of antipsychotic in schizophrenia.

Nucleosome assembly protein 1-like 5 alleviates Alzheimer's disease-like pathological characteristics in a cell model

Alzheimer's disease (AD) remains one of the most common dementias of neurodegenerative disease-related diseases. Nucleosome assembly protein 1-like 5 (NAP1L5) belongs to the NAP1L protein family, which acts as a histone chaperone. However, the function and mechanism of NAP1L5 in AD are still unclear. Bioinformatics analysis, RT-qPCR, and Western blotting results showed that NAP1L5 was downregulated in the brain tissues of AD patients and a mouse cell model of AD. NAP1L5 overexpression alleviated (Amyloid-β precursor protein) APP metabolism and Tau phosphorylation. We further demonstrated that NAP1L5 regulated the AD-like pathological characteristics through the GSK3B/Wnt/β-Catenin signaling pathway. Moreover, we showed that the Wnt/β-Catenin signaling pathway, regulated by NAP1L5, was mediated by AQP1-mediated mechanism in N2a-APP695sw cell. In sum, these results suggested that NAP1L5 overexpression has neuroprotective effects and might act as potential biomarker and target for the diagnosis and treatment of AD.

Scalp Electroacupuncture Promotes Angiogenesis after Stroke in Rats by Activation of Wnt/β-Catenin Signal Pathway

Background

Scalp acupuncture is a contemporary acupuncture method based on the fundamental theories of traditional acupuncture, which has been widely used in patients with stroke in China. However, the effectiveness is controversial due to lack of solid experimental evidence.

Methods

In this study, a rat model of cerebral ischemia-reperfusion injury (CIRI) was established by the middle cerebral artery occlusion/recirculation. The efficacy of scalp acupuncture against CIRI was evaluated by the mNSS scores, TTC staining for brain slices, and laser Doppler perfusion imaging. Immunohistochemical staining for angiogenetic factors indicated the vascularization after CIRI, including VEGF, Ang2, and bFGF. Activation of the Wnt/β-catenin signaling pathway and p-GSK3β (ser9)/VEGF pathway in the injured brain tissues was assessed by western blotting and qRT-PCR.

Results

On the 7, 14, and 21 days after CIRI, scalp acupuncture could reduce the mNSS scores, decrease the cerebral infarction area, and accelerate the recirculation of ischemic brain tissues. VEGF, FLK1, bFGF, and Ang2 were upregulated on both the mRNA and protein levels in the ischemic brain tissues of the AC group, suggesting that the recirculation might result from angiogenesis, which was also confirmed with the IHC staining in the angiogenetic markers of VEGF, Ang2, and bFGF. Moreover, Wnt3a, β-catenin, and cyclin D1 were also upregulated on both the mRNA and protein levels in the ischemic brain tissues of the AC group on day 7, 14, and 21, indicating that the Wnt/β-catenin signaling pathway was activated after the treatment of scalp acupuncture. In contrast, dikkoppf-1 (DKK1) pretreatment, a specific inhibitor for the Wnt/β-catenin signaling pathway, inactivated the Wnt3a/β-catenin signaling pathway and exacerbated the infarct size induced by the cerebral IR injury on day 7.

Conclusion

Together, our findings demonstrated a mechanism whereby scalp acupuncture led to the activation of Wnt/β-catenin signaling pathway, promoting angiogenetic factor expression and restoring blood perfusion in the ischemic zone.

Integrated co-expression network analysis uncovers novel tissue-specific genes in major depressive disorder and bipolar disorder

Tissue-specific gene expression has been found to be associated with multiple complex diseases including cancer, metabolic disease, aging, etc. However, few studies of brain-tissue-specific gene expression patterns have been reported, especially in psychiatric disorders. In this study, we performed joint analysis on large-scale transcriptome multi-tissue data to investigate tissue-specific expression patterns in major depressive disorder (MDD) and bipolar disorder (BP). We established the strategies of identifying tissues-specific modules, annotated pathways for elucidating biological functions of tissues, and tissue-specific genes based on weighted gene co-expression network analysis (WGCNA) and robust rank aggregation (RRA) with transcriptional profiling data from different human tissues and genome wide association study (GWAS) data, which have been expanded into overlapping tissue-specific modules and genes sharing with MDD and BP. Nine tissue-specific modules were identified and distributed across the four tissues in the MDD and six modules in the BP. In general, the annotated biological functions of differentially expressed genes (DEGs) in blood were mainly involved in MDD and BP progression through immune response, while those in the brain were in neuron and neuroendocrine response. Tissue-specific genes of the prefrontal cortex (PFC) in MDD-, such as IGFBP2 and HTR1A, were involved in disease-related functions, such as response to glucocorticoid, taste transduction, and tissue-specific genes of PFC in BP-, such as CHRM5 and LTB4R2, were involved in neuroactive ligand-receptor interaction. We also found PFC tissue-specific genes including SST and CRHBP were shared in MDD-BP, SST was enriched in neuroactive ligand-receptor interaction, and CRHBP shown was related to the regulation of hormone secretion and hormone transport.

A GWAS top hit for circulating leptin is associated with weight gain but not with leptin protein levels in lithium-augmented patients with major depression

Lithium-treated patients often suffer from weight gain as a common adverse event. In an earlier investigation, we found an impact of two single-nucleotide polymorphisms (rs10487506 and rs2278815) at the leptin gene on weight gain but not on leptin protein levels in serum under lithium augmentation. A recent genome-wide association study identified a polymorphism at the leptin gene locus (rs10487505) associated with circulating leptin protein levels. To characterize potential effects of this variant in acute major depressive disorder, we investigated body mass indices from 180 lithium-augmented patients and serum concentrations of leptin protein from 89 patients using linear mixed model analyses and rs6979832, a proxy SNP of rs10487505. Body mass index was measured before and after 4 weeks of lithium augmentation, in a subsample also after 4 and 7 months. Leptin serum levels were measured before and during lithium augmentation. G-allele homozygotes of rs6979832 had a significantly lower body mass index increase during observation compared to A-allele hetero- and homozygotes. However, we found no influence on leptin serum levels. Joint analyses of rs6979832 with the previously investigated polymorphisms rs10487506 and rs2278815, and expressed quantitative trait data, suggest a complex interplay between SNP alleles at the leptin locus. These results strongly support our earlier findings that common genetic variation at the leptin gene locus may be involved in lithium augmentation-associated weight gain in major depressive disorder.

Insights into the Regulation on Proliferation and Differentiation of Stem Leydig Cells

Male hypogonadism is a clinical syndrome caused by testosterone deficiency. Hypogonadism can be caused by testicular disease (primary hypogonadism) or hypothalamic-pituitary dysfunction (secondary hypogonadism). The present strategy for treating hypogonadism is the administration of exogenous testosterone. But exogenous testosterone is reported to have negative side effects including adverse cardiovascular events and disruption of physiological spermatogenesis probably due to its inability to mimic the physiological circadian rhythm of testosterone secretion in vivo. In recent years, a growing number of articles demonstrated that stem Leydig cells (SLCs) can not only differentiate into functional Leydig cells (LCs) in vivo to replace chemically disrupted LCs, but also secrete testosterone in a physiological pattern. The proliferation and differentiation of SLCs are regulated by various factors. However, the mechanisms involved in regulating the development of SLCs remain to be summarized. Factors involved in the regulation of SLCs can be divided into environmental pollutants, growth factors, cytokine and hormones. Environmental pollutants such as Perfluorooctanoic acid (PFOA) and Triphenyltin (TPT) could suppress SLCs proliferation or differentiation. Growth factors including FGF1, FGF16, NGF and activin A are essential for the maintenance of SLCs self-renewal and differentiation. Interleukin 6 family could inhibit differentiation of SLCs. Among hormones, dexamethasone suppresses SLCs differentiation, while aldosterone suppresses their proliferation. The present review focuses on new progress about factors regulating SLC's proliferation and differentiation which will undoubtedly deepen our insights into SLCs and help make better clinical use of them. Different factors affect on the proliferation and differentiation of stem Leydig cells. Firstly, each rat was intraperitoneally injected EDS so as to deplete Leydig cells from the adult testis. Secondly, the CD51+ or CD90+ cells from the testis of rats are SLCs, and the p75+ cells from human adult testes are human SLCs. These SLCs in the testis start to proliferate and some of them differentiate into LCs. Thirdly, during the SLCs regeneration period, researchers could explore different function of those factors (pollutants, growth factors, cytokines and hormones) towards SLCs.

Genome-wide DNA methylation analysis of peripheral blood cells derived from patients with first-episode schizophrenia in the Chinese Han population

Schizophrenia is a severe neuropsychiatric disorder with core features including hallucinations, delusions, and cognition deficits. Accumulating evidence has implicated abnormal DNA methylation in the development of schizophrenia. However, the mechanisms by which DNA methylation changes alter the risk for schizophrenia remain largely unknown. We recently carried out a DNA methylome study of peripheral blood samples from 469 first-episode patients with schizophrenia and 476 age- and gender-matched healthy controls of Han Chinese origin. Genomic DNA methylation patterns were quantified using an Illumina Infinium Human MethylationEPIC BeadChip. We identified multiple differentially methylated positions (DMPs) and regions between patients and controls. The most significant DMPs were annotated to genes C17orf53, THAP1 and KCNQ4 (K_V7.4), with Bonferroni-adjusted P values of [Formula: see text], [Formula: see text], and [Formula: see text], respectively. In particular, KCNQ4 encodes a voltage-gated potassium channel of the K_V7 family, which is linked to neuronal excitability. The genes associated with top-ranked DMPs also included many genes involved in nervous system development, such as LIMK2 and TMOD2. Gene ontology analysis of the differentially methylated genes further identified strong enrichment of neuronal networks, including neuron projection extension, axonogenesis and neuron apoptotic process. Finally, we provided evidence that schizophrenia-associated epigenetic alterations co-localize with genetic susceptibility loci. By focusing on first-episode schizophrenia patients, our investigation lends particularly strong support for an important role of DNA methylation in schizophrenia pathogenesis unconfounded by the effects of long-term antipsychotic medication or disease progression. The observed DNA methylation aberrations in schizophrenia patients could potentially provide a valuable resource for identifying diagnostic biomarkers and developing novel therapeutic targets to benefit schizophrenia patients.

Potential Roles of the WNT Signaling Pathway in Amyotrophic Lateral Sclerosis

The WNT signaling pathway plays an important role in the physiological and pathophysiological processes of the central nervous system and the neurodegenerative disease amyotrophic lateral sclerosis (ALS). We reviewed the literature pertinent to WNT/β–catenin signaling in ALS from cellular studies, animal models, and human clinical trials. WNT, WNT receptors, and other components of the WNT signaling pathway are expressed in both ALS patients and transgenic mice, and are involved in the pathogenesis of ALS. Studies have shown that abnormal activation of the WNT/β–catenin signaling pathway is related to neuronal degeneration and glial cell proliferation. WNT/Ca²⁺ signaling is associated with the pro–inflammatory phenotype of microglia; data on the muscle skeletal receptor Tyr kinase receptor in superoxide dismutase–1–G93A mice indicate that gene therapy is necessary for successful treatment of ALS. The varying profiles of lipoprotein receptor–related protein 4 antibodies in different ethnic groups suggest that individual treatment and multifactorial personalized approaches may be necessary for effective ALS therapy. In conclusion, the WNT signaling pathway is important to the ALS disease process, making it a likely therapeutic target.

Lithium alleviates blood-brain barrier breakdown after cerebral ischemia and reperfusion by upregulating endothelial Wnt/β-catenin signaling in mice

Although upregulation of endothelial Wnt/β-catenin signaling may be used to treat blood-brain barrier (BBB) breakdown caused by cerebral ischemia/reperfusion injury, no agents based on this mechanism are available clinically. Lithium, a medication used for treating bipolar mood disorders, upregulates Wnt/β-catenin signaling, but whether lithium alleviates BBB breakdown after ischemic stroke by upregulating endothelial Wnt/β-catenin signaling is unclear. Here, we evaluated the BBB-protective effect of lithium in adult mice with 1-h middle cerebral artery occlusion and 48-h reperfusion (MCAO/R) by determining neurological outcomes, BBB function and related molecular components. Furthermore, we assessed the effect and dependence of lithium on Wnt/β-catenin signaling in brain microvascular endothelial cells in cell culture and in mice with conditional endothelial knockout of Wnt7 co-receptor Gpr124. Our data show that lithium treatment (3 mmol/kg) significantly decreased infarct volume (34.1 ± 1.8% versus 58.3 ± 2.8% in vehicle controls, P < 0.0001) and improved neurological outcomes of mice following MCAO/R. Importantly, lithium significantly increased BBB integrity shown by reduction of Evans blue leakage (by 45.7%, P = 0.0064) and blood IgG extravasation (by 65.8%, P < 0.0001) into infarcted brain tissue. Mechanistically, lithium upregulated the activity of endothelial Wnt/β-catenin signaling in vivo and in vitro, increased the protein levels of tight junctions (Claudin-5 and ZO-1), and reduced MMP-9 expression. Furthermore, the protective effect of lithium on cerebral damage and BBB integrity was abolished in endothelial Gpr124 knockout mice, indicating the protection of lithium on BBB was mainly dependent on the Gpr124-mediated endothelial Wnt/β-catenin signaling. Taken together, our findings indicate that lithium may serve as a therapeutic candidate for treating the BBB breakdown in the early stage of ischemic stroke following reperfusion therapy.

[Lithium in the psychopharmacology of affective disorders and mechanisms of its effects on cellular physiology]

However, despite successful use of lithium in the treatment of affective disorders for almost 40 years, the mechanisms of its therapeutic action are still poorly understood. This review presents and summarizes the current literature about the use of lithium in treatment of affective disorders, as well as its effects on cellular physiology, with a separate description of the effect of this ion on the functioning of nerve tissue and ion-molecular mechanisms.

Evaluation of 2D:4D digit ratio in bipolar 1 disorder patients and its relationship with treatment response

BACKGROUND

The role of sex steroids in bipolar disorder (BD) has been demonstrated in adults. We aimed to evaluate the 2D:4D ratio, which indirectly reflects prenatal sex steroids, in BD. Another purpose of this study was to determine the relationship between clinical features, especially lithium response, and digit ratio.

METHODS

The study included 74 patients with bipolar 1 disorder and 74 healthy individuals matched according to age, gender, and educational status. The digit ratio was calculated by dividing the index finger (2D) length by the ring finger (4D) length in both hands. A lithium response scale was used to evaluate the lithium response history.

RESULTS

There was no difference in 2D:4D ratio between the patients and controls in either right or left hands. The digit ratio was not different between groups with and without suicide attempts. The 2D:4D ratio in the patient group was lower in individuals unresponsive to lithium therapy than in partial and good responders for both right and left hands.

DISCUSSION

According to the results of our study, the 2D:4D ratio in the BD group was not different from healthy controls but was lower in patients unresponsive to lithium. In this respect, the 2D:4D ratio can be considered as a biomarker for lithium response in BD. In large-sample studies, the 2D:4D ratio should be investigated for pathophysiology and treatment response of BD.

High Dosage Lithium Treatment Induces DNA Damage and p57Kip2 Decrease

Lithium salt is the first-line therapeutic option for bipolar disorder and has been proposed as a potential antitumoral drug. The effects of LiCl treatment were investigated in SH-SY5Y, a human neuroblastoma cell line and an in vitro model of dopaminergic neuronal differentiation. LiCl, at the dosage used in psychiatric treatment, does not affect cell proliferation, while at higher doses it delays the SH-SY5Y cell division cycle and for prolonged usage reduces cell viability. Moreover, the ion treatment affects DNA integrity as demonstrated by accumulation of p53 and γH2AX (the phosphorylated form of H2AX histone), two important markers of genome damage. p57^Kip2, a CIP/Kip protein, is required for proper neuronal maturation and represents a main factor of response to stress including genotoxicity. We evaluated the effect of lithium on p57^Kip2 levels. Unexpectedly, we found that lithium downregulates the level of p57^Kip2 in a dose-dependent manner, mainly acting at the transcriptional level. A number of different approaches, mostly based on p57^Kip2 content handling, confirmed that the CKI/Kip reduction plays a key role in the DNA damage activated by lithium and suggests the unanticipated view that p57^Kip2 might be involved in DNA double-strand break responses. In conclusion, our study identified novel roles for p57^Kip2 in the molecular mechanism of lithium at high concentration and, more in general, in the process of DNA repair.

Maternal lithium chloride exposure alters the neuroendocrine-cytokine axis in neonatal albino rats

The aim of this work was to clarify whether maternal lithium chloride (LiCl) exposure disrupts the neonatal neuroendocrine-cytokine axis. Pregnant Wistar rats were orally administrated 50 mg LiCl/kg b.wt. from gestational day (GD) 1 to postpartum day 28. Maternal administration of LiCl induced a hypothyroid state in both dams and their neonates compared to the control dams and neonates at lactation days (LDs) 14, 21 and 28, where the levels of serum free triiodothyronine (FT3) and free thyroxin (FT4) were decreased and the level of serum thyrotropin (TSH) level was increased. A noticeable depression in maternal body weight gain, neonatal body weight and neonatal serum growth hormone (GH) was observed on all examined postnatal days (PNDs; 14, 21 and 28). A single abortion case was recorded at GD 17, and three dead neonates were noted at birth in the LiCl-treated group. Maternal administration of LiCl disturbed the levels of neonatal serum tumor necrosis factor-alpha (TNF-α), transforming growth factor-beta (TGF-β), interleukin-1 beta (IL-1β), interferon-gamma (INF-γ), leptin, adiponectin and resistin at all tested PNDs compared to the control group. This administration produced a stimulatory action on the level of neonatal cerebral serotonin (5-HT) at PND 14 and on the level of neonatal cerebral norepinephrine (NE) at PNDs 21 and 28. However, this administration produced an inhibitory action on the level of neonatal cerebral dopamine (DA) at all examined PNDs and on the level of neonatal cerebral NE at PND 14 and the level of neonatal cerebral 5-HT at PNDs 21 and 28 compared to the corresponding control group. Thus, maternal LiCl exposure-induced hypothyroidism disrupts the neonatal neuroendocrine-cytokine system, which delay cerebral development.

New insights into Wnt signaling alterations in amyotrophic lateral sclerosis: a potential therapeutic target?

Amyotrophic lateral sclerosis is a fatal neurodegenerative disorder characterized by upper and lower motor neuron degeneration, which leads to progressive paralysis of skeletal muscles and, ultimately, respiratory failure between 2–5 years after symptom onset. Unfortunately, currently accepted treatments for amyotrophic lateral sclerosis are extremely scarce and only provide modest benefit. As a consequence, a great effort is being done by the scientific community in order to achieve a better understanding of the different molecular and cellular processes that influence the progression and/or outcome of this neuropathological condition and, therefore, unravel new potential targets for therapeutic intervention. Interestingly, a growing number of experimental evidences have recently shown that, besides its well-known physiological roles in the developing and adult central nervous system, the Wnt family of proteins is involved in different neuropathological conditions, including amyotrophic lateral sclerosis. These proteins are able to modulate, at least, three different signaling pathways, usually known as canonical (β-catenin dependent) and non-canonical (β-catenin independent) signaling pathways. In the present review, we aim to provide a general overview of the current knowledge that supports the relationship between the Wnt family of proteins and its associated signaling pathways and amyotrophic lateral sclerosis pathology, as well as their possible mechanisms of action. Altogether, the currently available knowledge suggests that Wnt signaling modulation might be a promising therapeutic approach to ameliorate the histopathological and functional deficits associated to amyotrophic lateral sclerosis, and thus improve the progression and outcome of this neuropathology.

Leptin gene polymorphisms are associated with weight gain during lithium augmentation in patients with major depression

Weight gain is a common adverse effect of lithium augmentation. Previous studies indicate an impact of genetic variants at the leptin gene on weight gain as a consequence of psychopharmacological treatment. The primary aim of our study was to identify variants at the leptin locus that might predict lithium-induced weight gain. The secondary aim was to investigate if these variants modulate leptin levels. In 180 patients with acute major depressive disorder, body mass index was measured before and after 4 weeks of lithium augmentation, in a subsample also after 4 and/or 7 months. In a subsample of 89 patients, leptin serum concentrations were measured before and during lithium augmentation. We used linear mixed model analyzes to investigate the effects of 2 polymorphisms at the leptin locus (rs4731426 and rs7799039, employing the respective proxy SNPs rs2278815 and rs10487506) on changes in body mass index and leptin levels. For both polymorphisms, which are in high linkage disequilibrium, body mass index was significantly lower in homozygous A-allele carriers than in carriers of other genotypes at baseline. Over the follow-up period, body mass index increased less in homozygous A-allele carriers of rs4731426 than in carriers of other genotypes. This was not the case for rs7799039. Neither polymorphism modulated leptin protein expression. Our study strongly supports the hypothesis that genetic variability at the leptin locus is involved in lithium augmentation-associated weight gain in major depressive disorder. Furthermore, Genotype-Tissue Expression data provide strong evidence that rs4731426 influences the expression of leptin messenger ribonucleic acid in fibroblasts.

Decrease of GSK-3β Activity in the Anterior Cingulate Cortex of Shank3b -/- Mice Contributes to Synaptic and Social Deficiency

Social deficiency is one of the core syndromes of autism spectrum disorders (ASD), for which the underlying developmental mechanism still remains elusive. Anterior cingulate cortex (ACC) plays a key role in integrating social information and regulating social behavior. Recent studies have indicated that synaptic dysfunction in ACC is essential for ASD social defects. In the present study, we investigated the development of synapses and the roles of glycogen synthase kinase 3β (GSK-3β), which mediates multiple synaptic signaling pathways in ACC by using Shank3b^−/− mice (a widely used ASD mouse model). Our data revealed that Shank3b mutation abolished the social induced c-Fos expression in ACC. From 4 weeks post-birth, neurons in Shank3b^−/− ACC exhibited an obvious decrease in spine density and stubby spines. The length and thickness of post-synaptic density (PSD), the expression of vesicular glutamate transporter 2 (vGlut2) and glutamate receptor 2 (GluR2), and the frequency of miniature excitatory post-synaptic currents (mEPSCs) were significantly reduced in Shank3b^−/−ACC. Interestingly, the levels of phosphorylated GSK-3β (Ser9), which inhibits the activity of GSK-3β, decreased along the same time course as the levels of GluR2 increased in ACC during development. Shank3b mutation leads to a dramatic increase of pGSK-3β (Ser9), and decrease of pPSD95 (a substrate of GSK-3β) and GluR2. Local delivery of AAV expressing constitutively active GSK-3β restored the expression of GluR2, increased the spine density and the number of mature spines. More importantly, active GSK-3β significantly promoted the social activity of Shank3b^−/− mice. These data, in together, indicate that decrease of GSK-3β activity in ACC may contribute to the synaptic and social defects of Shank3b^−/− mice. Enhancing GSK-3β activity may be utilized to treat ASD in the future.

Lithium chloride attenuates suppressed differentiation induced by mechanical strain in cementoblasts

Aim: The purpose of this study was to investigate the influence of mechanical strain on OCCM-30 cementoblast differentiation and Wnt/β-catenin pathway activity. Materials and Methods: Mechanical tension in the form of 2500-µ strain was applied to the cells using the Forcel four-point bending system, with or without the Wnt signaling activator, lithium chloride. Changes in cell differentiation and the expression of Wnt/β-catenin pathway components in response to strain and lithium chloride were assessed by real-time PCR, immunofluorescence, and western blotting. Results: The mRNA expression levels of the cementoblastogenesis-related genes alkaline phosphatase, runt-related transcription factor 2, and collagen 1, were decreased with mechanical strain. Similarly, the Wnt signaling pathway component genes LRP5, AXIN2, and LEF1 were decreased. The immunofluorescence assay demonstrated that scant β-catenin underwent nuclear translocation after the cells were subjected to mechanical strain. Moreover, western blotting showed that the protein levels of both β-catenin and phosphorylated β-catenin were increased after mechanical strain. In the presence of lithium chloride, the differentiation that was suppressed by mechanical strain was attenuated. Conclusions: 2500-µ strain mechanical strain inhibited cementoblast differentiation activity in vitro, which could be alleviated by actviating Wnt/β-catenin signaling using lithium chloride.

Anticancer effect of the traditional Chinese medicine herb Maytenus compound via the EGFR/PI3K/AKT/GSK3β pathway

Background

Cancer is a leading cause of death worldwide; folk anticancer medicinal plants have applied for cancer treatment. The Maytenus compound tablet as traditional Chinese compound medicine has been approved for alleviating hyperplasia of mammary glands, whether it can inhibit cancer still unknown. The study was to evaluate the anticancer activity of the Maytenus compound tablet.

Methods

MTS assay evaluated the anti-proliferation effect of the Maytenus compound on H226, A2058, 786O and HeLa cancer cells and two normal epithelial cell lines, namely, 16HBE and Hecate. Nude mouse xenograft tumor model using H226 and HeLa cells examined the drug’s anticancer effect in vivo. Western blot assay studied the possible mechanism.

Results

The Maytenus compound indicated obvious ability to against proliferation in four strains of cancer cells, particularly against H226 cells by an IC50 of 85.47±10.06 µg/mL and against HeLa cells by an IC50 of 128.74±17.46 µg/mL. However, it had a low cytotoxicity in human normal epithelial cell lines 16HBE with an IC50 of 4,555.86±25.21 µg/mL and Hecate with an IC50 of 833.56±181.88 µg/mL. The Maytenus compound at the 2.45 g/kg oral dosages inhibited the proliferation of H226 cells and HeLa cells in nude mouse with inhibitory rates of 36.06% and 26.45%, respectively, and no organ toxicity. The Maytenus compound could significantly downregulate the expression of pEGFR, pPI3K, pAKT, pGSK3β, β-catenin, and c-MYC and upregulate the protein expression of GSK3β.

Conclusions

The Maytenus compound has significant anticancer activities against human cancer H226 and HeLa cells both in vitro and in vivo, highlighting it may be an anticancer medicine.

Lithium-induced gene expression alterations in two peripheral cell models of bipolar disorder

Objectives: The aim of our study was to investigate molecular mechanisms of lithium action by studying the gene expression profile of peripheral cell models generated from bipolar patients (BD) and healthy controls (HC). Methods: EBV-immortalised lymphoblastoid cells (LCLs) and fibroblast cells from BD and HC were incubated with either lithium chloride or plain medium for 3 weeks. We first conducted a microarray gene expression study. The most promising differentially regulated genes in terms of lithium-associated or disorder-associated pathways were then replicated by quantitative real-time PCR (qRT-PCR). Results: The pooled microarray analysis showed 459 genes to be differentially regulated in BD compared to HC and 58 due to lithium treatment in LCLs, and 295 genes to be differentially regulated in BD compared to HC and five due to lithium treatment in fibroblasts. After correction for multiple comparison, EPHB1 disorder × treatment interactions remained significant in LCLs validated by qRT-PCR. In the control group, lithium influenced the expression of ANP32E, PLEKHA2, KCNK1, PRKCH, ST3GAL6 and AIF1. In bipolar and control fibroblast cells lithium treatment decreased FGF9 expression. Conclusions: The differentially regulated genes in our study add evidence for the relevance of inflammation, neuronal/glial development, phosphatidylinositol second-messenger pathway and ion channels in the mode of action of lithium.

The effect of lithium chloride on the attenuation of cognitive impairment in experimental hypoglycemic rats

BACKGROUND

Hypoglycemia is the most common complication in the treatment of diabetes mellitus. Accumulating evidence indicated that severe hypoglycemia could induce cognitive impairment. However, the molecular mechanism of regulating this progress is largely unknown.

METHODS

We established a model of insulin-induced recurrent hypoglycemia in adult male Wistar rats (n = 40). Lithium chloride was injected after hypoglycemia once a day for consecutive 30 days. The loss of cognition function was evaluated by water maze test in these hypoglycemic rats. Glial cells activation and Wnt and inflammatory cytokines IL-1β, IL-6, IL-4, IL-10, TGFβ and TNFα expression were further examined to determine the mechanism of cognitive function impairment.

RESULTS

Hypoglycemia could induce impairment of cognitive function in rats and administration of lithium chloride could partly attenuate cognitive impairment compared to the control (p < 0.05). Lithium chloride could significantly up-regulate Wnt signaling and reduce hypoglycemia-induced neuronal death, glial cells activation and inflammatory response in the hippocampus of rats compared to the control (p < 0.05). The efficacy of lithium chloride could be reversed by injecting canonical Wnt signaling antagonist the dickkopf homolog 1.

CONCLUSION

Lithium chloride attenuated hypoglycemia-induced cognitive function impairment in rats; and it was associated with Wnt signaling up-regulation and reduction of inflammatory response. Our results suggested that activating Wnt signaling pathways and inhibiting inflammatory response were the therapeutic potential to prevent hypoglycemia-induced neurological damage.

A novel tumor suppressor SPINK5 targets Wnt/β-catenin signaling pathway in esophageal cancer

Esophageal cancer is one of the most common tumor in the world, and the morbidity rate is as high as 100/100 000 in some parts of China. Therefore, it is important and urgent to explore the pathogenesis of esophageal cancer and find new therapeutic targets for esophageal cancer. In this study, we found that a novel tumor suppressor SPINK5 is significantly reduced in the development of esophageal cancer, and is closely related to the pathological differentiation and lymph node metastasis of esophageal cancer via bioinformatics analysis and esophageal cancer tissue array. Further studies have found that SPINK5 is closely related to Wnt/β‐catenin signaling pathway by bioinformatics analysis and western blot. In esophageal cancer cells, SPINK5 overexpression can inhibit Wnt/β‐catenin signaling pathway. Combined with LiCl or MG‐132 treatment, SPINK5 can inhibit GSK3β phosphorylation and promote β‐catenin protein degradation, thus inhibit Wnt/β‐catenin signaling pathway. In vivo study, SPINK5 overexpression can significantly inhibit the growth of esophageal cancer cells. Our study shows that SPINK5 can inhibit the proliferation, migration, and invasion of esophageal cancer cells by inhibiting Wnt/β‐catenin signaling pathway, and thus plays an important role in the development of esophageal cancer, and may serve as a treatment target of esophageal cancer.

Metabolic rhythms: A framework for coordinating cellular function

Circadian clocks are widespread among eukaryotes and generally involve feedback loops coupled with metabolic processes and redox balance. The organising power of these oscillations has not only allowed organisms to anticipate day-night cycles, but also acts to temporally compartmentalise otherwise incompatible processes, enhance metabolic efficiency, make the system more robust to noise and propagate signals among cells. While daily rhythms and the function of the circadian transcription-translation loop have been the subject of extensive research over the past four decades, cycles of shorter period and respiratory oscillations, with which they are intertwined, have received less attention. Here, we describe features of yeast respiratory oscillations, which share many features with daily and 12 hr cellular oscillations in animal cells. This relatively simple system enables the analysis of dynamic rhythmic changes in metabolism, independent of cellular oscillations that are a product of the circadian transcription-translation feedback loop. Knowledge gained from studying ultradian oscillations in yeast will lead to a better understanding of the basic mechanistic principles and evolutionary origins of oscillatory behaviour among eukaryotes.

Exploring the Wnt signaling pathway in schizophrenia and bipolar disorder

The Wnt signaling pathway plays a crucial role in neurodevelopment and in regulating the function and structure of the adult nervous system. Schizophrenia (SCZ) and bipolar disorder (BD) are severe mental disorders with evidence of subtle neurodevelopmental, structural and functional neuronal abnormalities. We aimed to elucidate the role of aberrant regulation of the Wnt system in these disorders by evaluating plasma levels of secreted Wnt modulators in patients (SCZ = 551 and BD = 246) and healthy controls (HCs = 639) using enzyme immune-assay. We also investigated the expression of 141 Wnt-related genes in whole blood in a subsample (SCZ = 338, BD = 241, and HCs = 263) using microarray analysis. Both SCZ and BD had dysregulated mRNA expression of Wnt-related genes favoring attenuated canonical (beta-catenin-dependent) signaling, and there were also indices of enhanced non-canonical Wnt signaling. In particular, FZD7, which may activate all Wnt pathways, but favors non-canonical signaling, and NFATc3, a downstream transcription factor and readout of the non-canonical Wnt/Ca²⁺ pathway, were significantly increased in SCZ and BD (p < 3 × 10^-4). Furthermore, patients had lower plasma levels of soluble dickkopf 1 and sclerostin (p < 0.01) compared with HC. Our findings suggest that SCZ and BD are characterized by abnormal Wnt gene expression and plasma protein levels, and we propose that drugs targeting the Wnt pathway may have a role in the treatment of severe mental disorders.

Gene expression associated with suicide attempts in US veterans

According to a recent report from the Office of Suicide Prevention in the US Department of Veterans Affairs, veterans represent 8.5% of the US population, but account for 18% of all deaths from suicide. The aim of this study of psychiatric patients (n=39; 87% male) was to compare blood gene expression data from veterans with a history of one or more suicide attempts to veterans who had never attempted suicide. The attempter and non-attempter groups were matched for age and race/ethnicity, and both groups included veterans with a diverse psychiatric history that included posttraumatic stress disorder (PTSD) and substance-use disorders. Veterans were interviewed for lifetime psychiatric history, including a detailed assessment of prior suicide attempts and provided a blood sample. Results of Ingenuity Pathway Analysis (IPA) identified several pathways associated with suicide attempts, including the mammalian target of rapamycin (mTOR) and WNT signaling pathways. These pathways are of particular interest, given their role in explaining pharmacological treatments for suicidal behavior, including the use of ketamine and lithium. These results suggest that findings observed in civilians are also relevant for veterans and provide a context for interpreting results observed in post-mortem samples. In conclusion, an emerging body of work that shows consistency in findings across blood and brain samples suggests that it might be possible to identify molecular predictors of suicide attempts.

Evidence towards RNA Binding Motif (RNP1, RRM) Protein 3 (RBM3) as a Potential Biomarker of Lithium Response in Bipolar Disorder Patients

Lithium has been used for more than six decades for the management of bipolar disorder (BD). In a previous transcriptomic study, we showed that patients affected by either BD or cluster headache, both disorders characterized by circadian disturbances and response to lithium in a subgroup of patients, have higher expression of the RNA binding motif (RNP1, RRM) protein 3 (RBM3) gene compared to controls. To investigate whether RBM3 could represent a biomarker of lithium response, we screened raw microarray expression data from lymphoblastoid cell lines (LCLs) derived from 20 BD patients, responders or non-responders to lithium. RBM3 was the most significantly differentially expressed gene in the list, being overexpressed in responders compared to non-responders (fold change = 2.0; p = 1.5 × 10^-16). We therefore sought to validate the microarray finding by quantitative reverse transcription polymerase chain reaction (RT-qPCR) and explore whether RBM3 expression was modulated by lithium treatment in vitro in LCLs as well as in human-derived neural progenitor cells (NPCs). Our findings confirmed the higher expression of RBM3 in responders compared to non-responders (fold change = 3.78; p = 0.0002). Lithium did not change RBM3 expression in LCLs in any of the groups, but it increased its expression in NPCs. While preliminary, our data suggest that higher levels of RBM3 might be required for better lithium response and that the expression of this gene could be modulated by lithium in a tissue-specific manner.

Wnt and GSK3 Signaling Pathways in Bipolar Disorder: Clinical and Therapeutic Implications

The neurobiology of bipolar disorder, a chronic and systemic ailment is not completely understood. The bipolar phenotype manifests in myriad ways, and psychopharmacological agents like lithium have long term beneficial effects. The enzyme glycogen synthase kinase 3 (GSK3) has come into focus, as lithium and several other mood stabilizing medications inhibit its activity. This kinase and its key upstream modulator, Wnt are dysregulated in mood disorders and there is a growing impetus to delineate the chief substrates involved in the development of these illnesses. In May 2016, a comprehensive literature search was undertaken which revealed that there is over activity of GSK3 in bipolar disorder with deleterious downstream effects like proinflammatory status, increased oxidative stress, and circadian dysregulation leading to declining neurotrophic support and enhanced apoptosis of neural elements. By developing specific GSK3 inhibitors the progressive worsening in bipolar disorder can be forestalled with improved prospects for the sufferers.

Lithium Reversibly Inhibits Schwann Cell Proliferation and Differentiation Without Inducing Myelin Loss

This study was undertaken to examine the bioactivity, specificity, and reversibility of lithium's action on the growth, survival, proliferation, and differentiation of cultured Schwann cells (SCs). In isolated SCs, lithium promoted a state of cell cycle arrest that featured extensive cell enlargement and c-Jun downregulation in the absence of increased expression of myelin-associated markers. In addition, lithium effectively prevented mitogen-induced S-phase entry without impairing cell viability. When lithium was administered together with differentiating concentrations of cyclic adenosine monophosphate (cAMP) analogs, a dramatic inhibition of the expression of the master regulator of myelination Krox-20 was observed. Likewise, lithium antagonized the cAMP-dependent expression of various myelin markers such as protein zero, periaxin, and galactocerebroside and allowed SCs to maintain high levels of expression of immature SC markers even in the presence of high levels of cAMP and low levels of c-Jun. Most importantly, the inhibitory action of lithium on SC proliferation and differentiation was shown to be dose dependent, specific, and reversible upon removal of lithium compounds. In SC-neuron cultures, lithium suppressed myelin sheath formation while preserving axonal integrity, SC-axon contact, and basal lamina formation. Lithium was unique in its ability to prevent the onset of myelination without promoting myelin degradation or SC dedifferentiation. To conclude, our results underscored an unexpected antagonistic action of lithium on SC mitogenesis and myelin gene expression. We suggest that lithium represents an attractive pharmacological agent to safely and reversibly suppress the onset of SC proliferation, differentiation, and myelination while maintaining the integrity of pre-existing myelinated fibers.

Pharmacological approaches to intervention in hypomyelinating and demyelinating white matter pathology

White matter disease afflicts both developing and mature central nervous systems. Both cell intrinsic and extrinsic dysregulation result in profound changes in cell survival, axonal metabolism and functional performance. Experimental models of developmental white matter (WM) injury and demyelination have not only delineated mechanisms of signaling and inflammation, but have also paved the way for the discovery of pharmacological approaches to intervention. These reagents have been shown to enhance protection of the mature oligodendrocyte cell, accelerate progenitor cell recruitment and/or differentiation, or attenuate pathological stimuli arising from the inflammatory response to injury. Here we highlight reports of studies in the CNS in which compounds, namely peptides, hormones, and small molecule agonists/antagonists, have been used in experimental animal models of demyelination and neonatal brain injury that affect aspects of excitotoxicity, oligodendrocyte development and survival, and progenitor cell function, and which have been demonstrated to attenuate damage and improve WM protection in experimental models of injury. The molecular targets of these agents include growth factor and neurotransmitter receptors, morphogens and their signaling components, nuclear receptors, as well as the processes of iron transport and actin binding. By surveying the current evidence in non-immune targets of both the immature and mature WM, we aim to better understand pharmacological approaches modulating endogenous oligodendroglia that show potential for success in the contexts of developmental and adult WM pathology. This article is part of the Special Issue entitled 'Oligodendrocytes in Health and Disease'.

Protective effect of lithium chloride against hypoglycemia-induced apoptosis in neuronal PC12 cell

Hypoglycemia is defined by an arbitrary plasma glucose level lower than 3.9mmol/L and is a most common and feared adverse effect of treatment of diabetes mellitus. Emerging evidences demonstrated that hypoglycemia could induce enhanced apoptosis. Lithium chloride (LiCl), a FDA approved drug clinically used for treatment of bipolar disorders, is recently proven having neuroprotection against various stresses in the cellular and animal models of neural disorders. Here, we have established a hypoglycemia model in vitro and assessed the neuroprotective efficacy of LiCl against hypoglycemia-induced apoptosis and the underlying cellular and molecular mechanisms. Our studies showed that LiCl protects against hypoglycemia-induced neurotoxicity in vitro. Exposure to hypoglycemia results in enhanced apoptosis and the underlying cellular and molecular mechanisms involved inhibition of the canonical Wnt signaling pathway by decreasing wnt3a levels, β-catenin levels and increasing GSK-3β levels, which was confirmed by the use of Wnt-specific activator LiCl. Hypoglycemia-induced apoptosis were significantly reversed by LiCl, leading to increased cell survival. LiCl also alters the expression/levels of the Wnt pathway genes/proteins, which were reduced due to exposed to hypoglycemia. Overall, our results conclude that LiCl provides neuroprotection against hypoglycemia-induced apoptosis via activation of the canonical Wnt signaling pathway.

Lithium accelerates functional motor recovery by improving remyelination of regenerating axons following ventral root avulsion and reimplantation

Brachial plexus injury (BPI) often involves the complete or partial avulsion of one or more of the cervical nerve roots, which leads to permanent paralysis of the innervated muscles. Reimplantation surgery has been attempted as a clinical treatment for brachial plexus root avulsion but has failed to achieve complete functional recovery. Lithium is a mood stabilizer drug that is used to treat bipolar disorder; however, its effects on spinal cord or peripheral nerve injuries have also been reported. The purpose of this study was to investigate whether lithium can improve functional motor recovery after ventral root avulsion and reimplantation in a rat model of BPI. The results showed that systemic treatment with a clinical dose of lithium promoted motor neuron outgrowth and increased the efficiency of motor unit regeneration through enhanced remyelination. An analysis of myelin-associated genes showed that the effects of lithium started during the early phase of remyelination and persisted through the late stage of the process. Efficient remyelination of the regenerated axons in the lithium-treated rats led to an earlier functional recovery. Therefore, we demonstrated that lithium might be a potential clinical treatment for BPI in combination with reimplantation surgery.

Inhibition of Glycogen Synthase Kinase-3: An Emerging Target in the Treatment of Traumatic Brain Injury

Although traumatic brain injury (TBI) has been a major public health concern for decades, the pathophysiological mechanism of TBI is not clearly understood, and an effective medical treatment of TBI is not available at present. Of particular concern is sustained TBI, which has a strong tendency to take a deteriorating neurodegenerative course into chronic traumatic encephalopathy (CTE) and dementia, including Alzheimer's disease. Tauopathy and beta amyloid (Aβ) plaques are known to be the key pathological markers of TBI, which contribute to the progressive deterioration associated with TBI such as CTE and Alzheimer's disease. The multiple lines of evidence strongly suggest that the inhibition of glycogen synthase kinase-3 (GSK-3) is a potential target in the treatment of TBI. GSK-3 constitutively inhibits neuroprotective processes and promotes apoptosis. After TBI, GSK-3 is inhibited through the receptor tyrosine kinase (RTK) and canonical Wnt signaling pathways as an innate neuroprotective mechanism against TBI. GSK-3 inhibition via GSK-3 inhibitors and drugs activating RTK or Wnt signaling is likely to reinforce the innate neuroprotective mechanism. GSK-3 inhibition studies using rodent TBI models demonstrate that GSK-3 inhibition produces diverse neuroprotective actions such as reducing the size of the traumatic injury, tauopathy, Aβ accumulation, and neuronal death, by releasing and activating neuroprotective substrates from GSK-3 inhibition. These effects are correlated with reduced TBI-induced behavioral and cognitive symptoms. Here, we review studies on the therapeutic effects of GSK-3 inhibition in TBI rodent models, and critically discuss the issues that these studies address.

Regulation of seminiferous tubule-associated stem Leydig cells in adult rat testes

Testicular Leydig cells are the primary source of testosterone in males. Adult Leydig cells have been shown to arise from stem cells present in the neonatal testis. Once established, adult Leydig cells turn over only slowly during adult life, but when these cells are eliminated experimentally from the adult testis, new Leydig cells rapidly reappear. As in the neonatal testis, stem cells in the adult testis are presumed to be the source of the new Leydig cells. As yet, the mechanisms involved in regulating the proliferation and differentiation of these stem cells remain unknown. We developed a unique in vitro system of cultured seminiferous tubules to assess the ability of factors from the seminiferous tubules to regulate the proliferation of the tubule-associated stem cells, and their subsequent entry into the Leydig cell lineage. The proliferation of the stem Leydig cells was stimulated by paracrine factors including Desert hedgehog (DHH), basic fibroblast growth factor (FGF2), platelet-derived growth factor (PDGF), and activin. Suppression of proliferation occurred with transforming growth factor β (TGF-β). The differentiation of the stem cells was regulated positively by DHH, lithium- induced signaling, and activin, and negatively by TGF-β, PDGFBB, and FGF2. DHH functioned as a commitment factor, inducing the transition of stem cells to the progenitor stage and thus into the Leydig cell lineage. Additionally, CD90 (Thy1) was found to be a unique stem cell surface marker that was used to obtain purified stem cells by flow cytometry.

Gallium as a Therapeutic Agent: A Thermodynamic Evaluation of the Competition between Ga(3+) and Fe(3+) Ions in Metalloproteins

Gallium has been employed (in the form of soluble salts) to fight various forms of cancer, infectious, and inflammatory diseases. The rationale behind this lies in the ability of Ga(3+) cation to mimic closely in appearance the native ferric ion, Fe(3+), thus interfering with the biological processes requiring ferric cofactors. However, Ga(3+) ion cannot participate in redox reactions and, when substituting for the "native" Fe(3+) ion in the enzyme active site, renders it inactive. Although a significant body of information on the Ga(3+)-Fe(3+) competition in biological systems has been accumulated, the intimate mechanism of the process is still not well understood and several questions remain: What are the basic physical principles governing the competition between the two trivalent cations in proteins? What type of metal centers are the most likely targets for gallium therapy? To what extent are the Fe(3+)-binding sites in the key enzyme ribonucleotide reductase vulnerable to Ga(3+) substitution? Here, we address these questions by studying the competition between Ga(3+) and Fe(3+) ions in model metal binding sites of various compositions and charge states. The results obtained are in line with available experimental data and shed light on the intimate mechanism of the Ga(3+)/Fe(3+) selectivity in various model metal binding sites and biological systems such as serum transferrin and ribonucleotide reductase.

Brain oscillations in bipolar disorder and lithium-induced changes

Electroencephalography (EEG) studies in patients with bipolar disorder have revealed lower amplitudes in brain oscillations. The aim of this review is to describe lithium-induced EEG changes in bipolar disorder and to discuss potential underlying factors. A literature survey about lithium-induced EEG changes in bipolar disorder was performed. Lithium consistently enhances magnitudes of brain oscillations in slow frequencies (delta and theta) in both resting-state EEG studies as well as event-related oscillations studies. Enhancement of magnitudes of beta oscillations is specific to event-related oscillations. Correlation between serum lithium levels and brain oscillations has been reported. Lithium-induced changes in brain oscillations might correspond to lithium-induced alterations in neurotransmitters, signaling cascades, plasticity, brain structure, or biophysical properties of lithium. Therefore, lithium-induced changes in brain oscillations could be promising biomarkers to assess the molecular mechanisms leading to variability in efficacy. Since the variability of lithium response in bipolar disorder is due to the genetic differences in the mechanisms involving lithium, it would be highly promising to assess the lithium-induced EEG changes as biomarkers in genetic studies.

Lithium in the treatment of bipolar disorder: pharmacology and pharmacogenetics

After decades of research, the mechanism of action of lithium in preventing recurrences of bipolar disorder remains only partially understood. Lithium research is complicated by the absence of suitable animal models of bipolar disorder and by having to rely on in vitro studies of peripheral tissues. A number of distinct hypotheses emerged over the years, but none has been conclusively supported or rejected. The common theme emerging from pharmacological and genetic studies is that lithium affects multiple steps in cellular signaling, usually enhancing basal and inhibiting stimulated activities. Some of the key nodes of these regulatory networks include GSK3 (glycogen synthase kinase 3), CREB (cAMP response element-binding protein) and Na(+)-K(+) ATPase. Genetic and pharmacogenetic studies are starting to generate promising findings, but remain limited by small sample sizes. As full responders to lithium seem to represent a unique clinical population, there is inherent value and need for studies of lithium responders. Such studies will be an opportunity to uncover specific effects of lithium in those individuals who clearly benefit from the treatment.

Downregulation of canonical Wnt signaling in hippocampus of SAMP8 mice

In the adult brain, canonical Wnt (Wnt/β-catenin) signaling modulates neuronal function, hippocampal neurogenesis, and synaptic plasticity. Indeed, growing evidence suggests that downregulation of Wnt signaling could be involved in the cognitive decline associated with aging and also with the physiopathology of Alzheimer's disease (AD). However, the molecular basis remains unknown. At present, SAMP8 is an experimental model that has been proposed for studying age-related neurodegenerative changes associated with aging and the pathogenesis of AD. Here, we examined Wnt signaling in the hippocampus of SAMP8 mice at 9 and 12 months of age, as well as in its control-strain SAMR1 mice. Our results showed increased Dickkopf-1 protein levels in SAMP8 with age, in addition to GSK-3 α/β activation and hyperphosphorylated tau. Consequently, higher β-catenin phosphorylation at Ser(33,37) and Thr(41), which promotes its degradation, along with a decrease in active β-catenin (ABC) in the nucleus, were observed in SAMP8, mainly at the age of 12 months. Moreover, nuclear levels of Dvl3 were lower in 9- and 12-month-old SAMP8 mice. Related to these findings, SAMP8 showed an increase in neuronal loss in the hippocampus that was associated with lower protein levels of the antiapoptotic protein and the Wnt target gene, Bcl-2, in addition to an increase in the proapototic protein Bax. Our results suggest a relationship between age-related downregulation of canonical Wnt signaling and neuronal loss observed in the hippocampus of SAMP8 mice. Thus, enhancing Wnt signaling may represent a novel neuroprotective strategy aimed at counteracting the cognitive decline that is associated not only with aging but also with AD.

Pharmacological and toxicological effects of lithium in zebrafish

Lithium is the paradigmatic treatment for bipolar disorder and has been widely used as a mood stabilizer due to its ability to reduce manic and depressive episodes, efficiency in long-term mood stabilization, and effectiveness in reducing suicide risks. Despite many decades of clinical use, the molecular targets of lithium are not completely understood. However, they are credited at least partially to glycogen synthase kinase 3 (GSK3) inhibition, mimicking and exacerbating Wnt signaling pathway activation. There has been a great effort to characterize lithium cellular and system actions, aiming to improve treatment effectiveness and reduce side effects. There is also a growing concern about lithium's impact as an environmental contaminant and its effects on development. In this scenario, zebrafish is a helpful model organism to gather more information on lithium's effects in different systems and developmental stages. The rapid external development, initial transparency, capacity to easily absorb substances, and little space required for maintenance and experimentation, among other advantages, make zebrafish a suitable model. In addition, zebrafish has been established as an effective model organism in behavioral and neuropharmacological studies, reacting to a wide range of psychoactive drugs, including lithium. So far only a limited number of studies evaluated the toxicological impact of lithium on zebrafish development and demonstrated morphological, physiological, and behavioral effects that may be informative regarding human findings. Further studies dedicated to characterize and evaluate the underlying mechanisms of the toxic effects and the potential impact of exposure on developing and adult individuals are necessary to establish safe clinical management guidelines for women with bipolar disorder of childbearing age and safety disposal guidelines for pharmaceutical neuroactive compounds.

Lithium attenuates IFN-β production and antiviral response via inhibition of TANK-binding kinase 1 kinase activity

Lithium salt is a widely used glycogen synthase kinase-3β inhibitor and effective drug for the treatment of psychiatric diseases. However, the effects of lithium in innate immune responses, especially in cellular antiviral responses, are unknown. In this study, we show that lithium chloride attenuates LPS-, polyinosinic-polycytidylic acid-, and Sendai virus-induced IFN-β production and IFN regulatory factor 3 activation in macrophages in a glycogen synthase kinase-3β-independent manner. The ability of the lithium to inhibit IFN-β production was confirmed in vivo, as mice treated with lithium chloride exhibited decreased levels of IFN-β upon Sendai virus infection. In vitro kinase assay demonstrates that lithium suppresses TANK-binding kinase 1 kinase activity. Consistently, lithium significantly enhanced the replication of vesicular stomatitis virus in vitro and in vivo. Severe infiltration of monocytes and tissue damage were observed in the lungs of control mice, compared with lithium-treated mice after virus infection. Our findings suggest lithium as an inhibitor of TANK-binding kinase 1 and potential target for the intervention of diseases with uncontrolled IFN-β production. Furthermore, lithium attenuates host defense to virus infection and may cause severely adverse effects in clinical applications.