Lithium protects against glucocorticoid induced neural progenitor cell apoptosis in the developing cerebellum

Accumulation and neuroprotective effects of lithium on hepatocellular carcinoma mice model

AIM

The peripheral tumor growth is accompanied by the accumulation of inflammatory mediators in the blood that can negatively influence blood-brain barrier function and neuronal structure and develop the cancer-associated depression. The aim of the study was to evaluate the neurobiological effects of lithium on hepatocellular carcinoma mice model.

METHODS

In this study we analyzed the locomotor activity of lithium-treated tumor-bearing mice using the Phenomaster instrument. Inductively coupled plasma mass-spectral analysis was used to determine lithium levels in blood, brain, liver, kidneys, tumors and muscle tissues. The prefrontal cortex neurons ultrastructure was assessed by transmission electron microscopy. Expression of BDNF, GRP78, EEA1, LAMP1, and LC3 beta in neurons was determined by immunohistochemical analysis.

RESULTS

A decrease in locomotor activity was found in animals with tumors. At the same time, the low expression levels of the neurotrophic factor BDNF and early endosomal marker EEA1 were revealed, as well as the decreased amount of synaptic vesicles and synapses was shown. Signs of endoplasmic reticulum stress and autophagy development in neurons of animals with tumors were noted. Lithium carbonate administration had a corrective effect on animal's behavior and the prefrontal cortex neurons structure.

CONCLUSIONS

In summary, lithium can restore the neuronal homeostasis in tumor-bearing mice.

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.

Is lithium neuroprotective? An updated mechanistic illustrated review

Neurodegeneration is a pathological process characterized by progressive neuronal impairment, dysfunction, and loss due to mitochondrial dysfunction, oxidative stress, inflammation, and apoptosis. Many studies have shown that lithium protects against neurodegeneration. Herein, we summarize recent clinical and laboratory studies on the neuroprotective effects of lithium against neurodegeneration and its potential to modulate mitochondrial dysfunction, oxidative stress, inflammation, and apoptosis. Recent findings indicate that lithium regulates critical intracellular pathways such as phosphatidylinositol-3 (PI3)/protein kinase B (Akt)/glycogen synthase kinase-3 (GSK3β) and PI3/Akt/response element-binding protein (CREB)/brain-derived neurotrophic factor (BDNF). We queried PubMed, Web of Science, Scopus, Elsevier, and other related databases using search terms related to lithium and its neuroprotective effect in various neurodegenerative diseases and events from January 2000 to May 2022. We reviewed the major findings and mechanisms proposed for the effects of lithium. Lithium's neuroprotective potential against neural cell degeneration is mediated by inducing anti-inflammatory factors, antioxidant enzymes, and free radical scavengers to prevent mitochondrial dysfunction. Lithium effects are regulated by two essential pathways: PI3/Akt/GSK3β and PI3/Akt/CREB/BDNF. Lithium acts as a neuroprotective agent against neurodegeneration by preventing inflammation, oxidative stress, apoptosis, and mitochondrial dysfunction using PI3/Akt/GSK3β and PI3/Akt/CREB/BDNF signaling pathways.

BMP/Smad Pathway Is Involved in Lithium Carbonate-Induced Neural-Tube Defects in Mice and Neural Stem Cells

Neural-tube defects (NTDs) are one type of the most serious birth defects. Studies have shown that inositol deficiency is closely related to the occurrence of NTDs. Bone morphogenetic protein (BMP)-mediated Smad signaling pathways have been implicated in neurogenesis and neural-tube closure. However, the role of the BMP/Smad pathway in inositol-deficiency-induced NTDs remains unclear. Inositol-deficiency models in C57 mice and mouse neural stem cells (mNSCs) were induced with Li₂CO₃ treatment or inositol withdrawal. The role of the BMP/Smad pathway in the regulation of cell proliferation and the development of NTDs was determined utilizing qRT-PCR, HE staining, Western blot, immunostaining, MTT assay, EdU staining, and flow cytometry. The intraperitoneal injection of Li₂CO₃ at Embryonic Day 7.5 induced the occurrence of NTDs. The mRNA levels of Bmp2, Bmp4, Smad1, Smad5, Smad8 and Runx2, the phosphorylation of Smad1/5/8, and the nuclear translocation of Runx2 were significantly increased in NTD embryonic brain tissues and mNSCs exposed to Li₂CO₃ or an inositol-free medium, which were suppressed by BMP receptor selective inhibitor LDN-193189. The Li₂CO₃-induced phosphorylation of Smad1/5/8 was inhibited by inositol supplementation. Cell proliferation was significantly promoted by Li₂CO₃ exposure or the absence of inositol in mNSCs, which was reversed by LDN-193189. These results suggest that the activation of the BMP/Smad signaling pathway might play an important role in the development of NTDs induced by maternal Li₂CO₃ exposure via inositol deficiency.

Lithium chloride prevents glucocorticoid-induced osteonecrosis of femoral heads and strengthens mesenchymal stem cell activity in rats

Background:

Accumulating evidence suggests that lithium influences mesenchymal stem cell (MSC) proliferation and osteogenic differentiation. As decreased bone formation in femoral heads is induced by glucocorticoids (GCs), we hypothesized that lithium has a protective effect on GC-induced osteonecrosis of femoral heads (ONFH).

Methods:

A rat ONFH model was induced by methylprednisolone (MP) and the effect of lithium chloride on the models was evaluated. Micro-computed tomography (CT)-based angiography and bone scanning were performed to analyze the vessels and bone structure in the femoral heads. Hematoxylin and eosin and immunohistochemical staining were performed to evaluate the trabecular structure and osteocalcin (OCN) expression, respectively. Bone marrow-derived MSCs were isolated from the models, and their proliferative and osteogenic ability was evaluated. Western blotting and quantitative real-time polymerase chain reaction were performed to detect osteogenic-related proteins including Runx2, alkaline phosphatase, and Collagen I.

Results:

Micro-CT analysis showed a high degree of osteonecrotic changes in the rats that received only MP injection. Treatment with lithium reduced this significantly in rats that received lithium (MP + Li group); while 18/20 of the femoral heads in the MP showed severe osteonecrosis, only 5/20 in the MP + Li showed mild osteonecrotic changes. The MP + Li group also displayed a higher vessel volume than the MP group (0.2193 mm³vs. 0.0811 mm³, P < 0.05), shown by micro-CT-based angiography. Furthermore, histological analysis showed better trabecular structures and more OCN expression in the femoral heads of the MP + Li group compared with the MP group. The ex vivo investigation indicated higher proliferative and osteogenic ability and upregulated osteogenic-related proteins in MSCs extracted from rats in the MP + Li group than that in the MP group.

Conclusions:

We concluded that lithium chloride has a significant protective effect on GC-induced ONFH in rats and that lithium also enhances MSC proliferation and osteogenic differentiation in rats after GC administration.

Lithium promotes malignant transformation of nontumorigenic cells in vitro

Because of the deficiency of water caused by the regional disparities of rainfall due to global warming, attention has been given to the use of well water as drinking water in developing countries. Our fieldwork study in Afghanistan showed that there was a maximum value of 3371 μg/L and an average value of 233 μg/L of lithium in well drinking water. Since the level of lithium in well water is higher than the levels in other countries, we investigated the health risk of lithium. After confirming no influence of ≤1000 μM lithium on cell viability, we found that lithium at concentrations of 100 and 500 μM promoted anchorage-independent growth of human immortalized keratinocytes (HaCaT) and lung epithelial cells (BEAS-2B) but not that of human keratinocytic carcinoma cells (HSC-5) or lung epithelial carcinoma cells (A549). The same concentrations of lithium also promoted phosphorylation of c-SRC and MEK/ERK but not that of AKT in the keratinocytes. Inhibitors of c-SRC (PP2) and MEK (PD98059) suppressed the lithium-induced increase in anchorage-independent growth of the keratinocytes. Our results suggested that lithium promoted transformation of nontumorigenic cells rather than progression of tumorigenic cells with preferential activation of the c-SRC/MEK/ERK pathway. Since previous pharmacokinetics studies indicated that it is possible for the serum level of lithium to reach 100 μM by drinking 2.5 L of water containing 3371 μg/L of lithium per day, the high level of lithium contamination in well drinking water in Kabul might be a potential oncogenic risk in humans.

Caspase-3 Mediated Cell Death in the Normal Development of the Mammalian Cerebellum

Caspase-3, onto which there is a convergence of the intrinsic and extrinsic apoptotic pathways, is the main executioner of apoptosis. We here review the current literature on the intervention of the protease in the execution of naturally occurring neuronal death (NOND) during cerebellar development. We will consider data on the most common altricial species (rat, mouse and rabbit), as well as humans. Among the different types of neurons and glia in cerebellum, there is ample evidence for an intervention of caspase-3 in the regulation of NOND of the post-mitotic cerebellar granule cells (CGCs) and Purkinje neurons, as a consequence of failure to establish proper synaptic contacts with target (secondary cell death). It seems possible that the GABAergic interneurons also undergo a similar type of secondary cell death, but the intervention of caspase-3 in this case still remains to be clarified in full. Remarkably, CGCs also undergo primary cell death at the precursor/pre-migratory stage of differentiation, in this instance without the intervention of caspase-3. Glial cells, as well, undergo a process of regulated cell death, but it seems possible that expression of caspase-3, at least in the Bergmann glia, is related to differentiation rather than death.

Dexmedetomidine protects against glucocorticoid induced progenitor cell apoptosis in neonatal mouse cerebellum

OBJECTIVES

Glucocorticoids (GCs) are used to improve respiratory mechanics in preterm infants despite clinical evidence linking neonatal GC therapy to cerebellar pathology. In developing mouse cerebellum, the GC dexamethasone (DEX) causes rapid GC-induced neural progenitor cell apoptosis (GINA). Focusing on pharmacological neuroprotection strategies, we investigated whether dexmedetomidine (DMT) protects against GINA.

METHODS

Neonatal mice were pretreated with DMT prior to DEX challenge. Additionally, we tested clonidine and yohimbine in vivo to determine mechanism of DMT neuroprotection. For in vitro studies, cerebellar neural progenitor cells were pretreated with DMT before DEX challenge.

RESULTS

In vivo, DMT attenuated GINA at 1 μg/kg and above, p < 0.0001. Clonidine significantly attenuated GINA, p < 0.0001, while yohimbine reversed DMT neuroprotection, p < 0.0001, suggesting DMT neuroprotection is likely mediated via adrenergic signaling. In vitro, DMT neuroprotection was achieved at 10 μM and above, p < 0.001, indicating DMT rescue is cell autonomous.

CONCLUSIONS

DMT affords dose-dependent neuroprotection from GINA at clinically relevant doses, an effect that is cell autonomous and likely mediated by α2 adrenergic receptor agonism. DMT co-administration with GCs may be an effective strategy to protect the neonatal brain from GINA while retaining the beneficial effects of GCs on respiratory mechanics.

Lithium chloride promotes neuronal differentiation of rat neural stem cells and enhances neural regeneration in Parkinson's disease model

Parkinson's disease (PD) is one of the most common neural degenerative disease, affecting millions of people globally. Great progress has been made in the PD treatment, and one of the most promising one is the stem cell-based therapy. Thus, studies on the differentiation of neural stem cells (NSCs) are important to the advancement in PD therapy. In this study, we used the rat NSCs to elucidate the role of Lithium in the proliferation and differentiation of NSCs by immunostaining against Ki67 and BrdU analysis as well as immunostaining against specific neuronal markers. We concluded that lithium chloride (LiCl) treatment could enhance the proliferation in NSCs and promote the dopaminergic neuronal differentiation of NSCs in vitro. This process was potentially mediated by Wnt signaling pathway. Using the 6-OHDA-induced PD models, we provided evidence to show that LiCl had the capacity to enhance the proliferation in NSCs and differentiation towards dopaminergic neurons in vivo. The beneficial effect of LiCl treatment was further validated by the fact that the motor function as well as learning and memory was improved in the PD models through Rotarod test and Morris water maze analysis. The learning and memory improvement was further supported by the increase in dendrite spine density in PD models receiving LiCl-treated NSCs. Through this study, we concluded that Lithium plays an important role in promoting NSCs' neuronal differentiation in vitro and improving the symptoms of PD models in vivo. It is of great significance that this work showed the potential application of Lithium in the PD therapy in the future.

Caffeine combined with sedative/anesthetic drugs triggers widespread neuroapoptosis in a mouse model of prematurity

OBJECTIVES

Caffeine (CAF) and sedative/anesthetic drugs (SADs) are often coadministered to premature infants in the neonatal intensive care unit (NICU). While SAD neurotoxicity in the developing brain is well established, it is not fully clear whether CAF interacts with SADs and whether this interaction is detrimental. Using a mouse model of prematurity, we hypothesized that CAF would increase apoptotic neurotoxicity when coadministered with SADs.

METHODS

Postnatal day 3 mice were treated with vehicle or 80 mg/kg CAF prior to challenge with 6 mg/kg midazolam, 40 mg/kg ketamine, or 40 μg/kg fentanyl. Six hours later, pups were sacrificed for activated caspase 3 (AC3) immunohistochemistry, and number of AC3 positive cells per mm³ throughout neocortex, hippocampus, caudate, thalamus, and colliculi was analyzed.

RESULTS

CAF caused a statistically significant increase in AC3 positive cells when coadministered with midazolam (p = 0.002), ketamine (p = 0.014), or fentanyl (p < 0.001). Our composite dataset suggests that the addition of CAF to these SADs has a supra-additive effect, causing more neurotoxicity than expected.

CONCLUSIONS

CAF may augment the neurotoxic action of SADs indicated for neonatal sedation/anesthesia in the NICU by triggering widespread apoptosis in the developing brains of premature infants.

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'.

Developmental Injury to the Cerebellar Cortex Following Hydroxyurea Treatment in Early Postnatal Life: An Immunohistochemical and Electron Microscopic Study

Postnatal development of the cerebellar cortex was studied in rats administered with a single dose (2 mg/g) of the cytotoxic agent hydroxyurea (HU) on postnatal day (P) 9 and collected at appropriate times ranging from 6 h to 45 days. Quantification of several parameters such as the density of pyknotic, mitotic, BrdU-positive, and vimentin-stained cells revealed that HU compromises the survival of the external granular layer (EGL) cells. Moreover, vimentin immunocytochemistry revealed overexpression and thicker immunoreactive glial processes in HU-treated rats. On the other hand, we also show that HU leads to the activation of apoptotic cellular events, resulting in a substantial number of dying EGL cells, as revealed by TUNEL staining and at the electron microscope level. Additionally, we quantified several features of the cerebellar cortex of rats exposed to HU in early postnatal life and collected in adulthood. Data analysis indicated that the analyzed parameters were less pronounced in rats administered with this agent. Moreover, we observed several alterations in the cerebellar cortex cytoarchitecture of rats injected with HU. Anomalies included ectopic placement of Purkinje cells and abnormities in the dendritic arbor of these macroneurons. Ectopic granule cells were also found in the molecular layer. These findings provide a clue for investigating the mechanisms of HU-induced toxicity during the development of the central nervous system. Our results also suggest that it is essential to avoid underestimating the adverse effects of this hydroxylated analog of urea when administered during early postnatal life.

LXR agonist rescued the deficit in the proliferation of the cerebellar granule cells induced by dexamethasone

Dexamethasone (DEX) exposure during early postnatal life produces permanent neuromotor and intellectual deficits and stunts cerebellar growth. The liver X receptor (LXR) plays important roles in CNS development. However, the effects of LXR on the DEX-mediated impairment of cerebellar development remain undetermined. Thus, mice were pretreated with LXR agonist TO901317 (TO) and were later exposed to DEX to evaluate its protective effects on DEX-mediated deficit during cerebellar development. The results showed that an acute exposure of DEX on postnatal day 7 resulted in a significant impairment in cerebellar development and decreased the proliferation of granule neuron precursors in the external granule layer of cerebellum. This effect was attenuated by pretreatment with TO. We further found that the decrease in the proliferation caused by DEX occurred via up-regulation of glucocorticoid receptor and p27kip1, which could be partially prevented by LXR agonist pretreatment. Overall, our results suggest that LXR agonist pretreatment could protect against DEX-induced deficits in cerebellar development in postnatal mice and may thus be perspective recruited to counteract such GC side effects.

Lithium Protects Against Anaesthesia Neurotoxicity In The Infant Primate Brain

Exposure of infant animals, including non-human primates (NHPs), to anaesthetic drugs causes apoptotic death of neurons and oligodendrocytes (oligos) and results in long-term neurodevelopmental impairment (NDI). Moreover, retrospective clinical studies document an association between anaesthesia exposure of human infants and significant increase in NDI. These findings pose a potentially serious dilemma because millions of human infants are exposed to anaesthetic drugs every year as part of routine medical care. Lithium (Li) at clinically established doses is neuroprotective in various cerebral injury models. We therefore investigated whether Li also protects against anaesthesia neurotoxicity in infant NHPs. On postnatal day 6 NHPs were anaesthetized with the widely used anaesthetic isoflurane (ISO) for 5 h employing the same standards as in a human pediatric surgery setting. Co-administration of Li completely prevented the acute ISO-induced neuroapoptosis and significantly reduced ISO-induced apoptosis of oligodendroglia. Our findings are highly encouraging as they suggest that a relatively simple pharmacological manipulation might protect the developing primate brain against the neurotoxic action of anaesthetic drugs while not interfering with the beneficial actions of these drugs. Further research is needed to determine Li’s potential to prevent long-term NDI resulting from ISO anaesthesia, and to establish its safety in human infants.

Lithium enhanced cell proliferation and differentiation of mesenchymal stem cells to neural cells in rat spinal cord

Lithium has been shown to inhibit apoptosis of neural progenitor cells (NPCs) and promote differentiation of NPCs. However, there was rare data to discuss the effects of lithium on neural differentiation of mesenchymal stem cells (MSCs). Here, we investigated the potential promotion of lithium to MSC proliferation and neural differentiation in vitro and after transplanted into the ventral horn of rat spinal cord in vivo. We found that lithium possesses the ability to promote proliferation of GFP-MSCs in a dose dependent manner as verified by growth curve and bromodeoxyuridine (BrdU) incorporation assays; While in neural induction medium, lithium (0.1 mM) promotes neural differentiation of GFP-MSCs as verified by immunostaining and quantitative analysis. After transplantation of GFP-MSCs into the rat spinal cord, lithium treatment enhanced cell survival and neural differentiation after transplantation as verified by immunohistochemistry. These data suggested that lithium could be a potential drug to augment the therapeutic efficiency of MSCs transplantation therapy in central nervous system (CNS) disorders.

Cellular commitment in the developing cerebellum

The mammalian cerebellum is located in the posterior cranial fossa and is critical for motor coordination and non-motor functions including cognitive and emotional processes. The anatomical structure of cerebellum is distinct with a three-layered cortex. During development, neurogenesis and fate decisions of cerebellar primordium cells are orchestrated through tightly controlled molecular events involving multiple genetic pathways. In this review, we will highlight the anatomical structure of human and mouse cerebellum, the cellular composition of developing cerebellum, and the underlying gene expression programs involved in cell fate commitments in the cerebellum. A critical evaluation of the cell death literature suggests that apoptosis occurs in ~5% of cerebellar cells, most shortly after mitosis. Apoptosis and cellular autophagy likely play significant roles in cerebellar development, we provide a comprehensive discussion of their role in cerebellar development and organization. We also address the possible function of unfolded protein response in regulation of cerebellar neurogenesis. We discuss recent advancements in understanding the epigenetic signature of cerebellar compartments and possible connections between DNA methylation, microRNAs and cerebellar neurodegeneration. Finally, we discuss genetic diseases associated with cerebellar dysfunction and their role in the aging cerebellum.