scholarly journals Lactate transport facilitates neurite outgrowth

2018 ◽  
Vol 38 (5) ◽  
Author(s):  
Kun Chen ◽  
Peng Cheng ◽  
Huan Wang ◽  
Shutao Gao ◽  
Xiao Li ◽  
...  

How glia affect neurite outgrowth during neural development has not been well elucidated. In the present study, we found that disruption of lactate production using 1,4-dideoxy-1,4-imino-D-arabinitol (DAB) and isofagomine significantly interfered with neurite outgrowth and that exogenous application of L-lactate rescued neurite growth failure. Monocarboxylate transporter-2-knockout, which blocked the lactate shuttle in neurons, showed a remarkable decrease in the length of axons and dendrites. We further demonstrated that Akt activity was decreased while glycogen synthase kinase 3β (GSK3β) activity was increased after astrocytic glycogen phosphorylase blockade. Additionally, GSK3βSer9 mutation reversed neurite growth failure caused by DAB and isofagomine. Our results suggested that lactate transportation played a critical role in neural development and disruption of the lactate shuttle in quiescent condition also affected neurite outgrowth in the central nervous system.

2020 ◽  
Vol 27 (37) ◽  
pp. 6384-6406 ◽  
Author(s):  
Zuo Zhang ◽  
Hongli Zhou ◽  
Jiyin Zhou

NG2-glia, also called Oligodendrocyte Precursor Cells (OPCs), account for approximately 5%-10% of the cells in the developing and adult brain and constitute the fifth major cell population in the central nervous system. NG2-glia express receptors and ion channels involved in rapid modulation of neuronal activities and signaling with neuronal synapses, which have functional significance in both physiological and pathological states. NG2-glia participate in quick signaling with peripheral neurons via direct synaptic touches in the developing and mature central nervous system. These distinctive glia perform the unique function of proliferating and differentiating into oligodendrocytes in the early developing brain, which is critical for axon myelin formation. In response to injury, NG2-glia can proliferate, migrate to the lesions, and differentiate into oligodendrocytes to form new myelin sheaths, which wrap around damaged axons and result in functional recovery. The capacity of NG2-glia to regulate their behavior and dynamics in response to neuronal activity and disease indicate their critical role in myelin preservation and remodeling in the physiological state and in repair in the pathological state. In this review, we provide a detailed summary of the characteristics of NG2-glia, including their heterogeneity, the regulators of their proliferation, and the modulators of their differentiation into oligodendrocytes.


Author(s):  
Jingjing Cong ◽  
Bei Cheng ◽  
Jinyu Liu ◽  
Ping He

AbstractVascular calcification (VC) is highly prevailing in cardiovascular disease, diabetes mellitus, and chronic kidney disease and, when present, is associated with cardiovascular events and mortality. The osteogenic differentiation of vascular smooth muscle cells (VSMCs) is regarded as the foundation for mediating VC. Related transcriptional enhancer factor (RTEF-1), also named as transcriptional enhanced associate domain (TEAD) 4 or transcriptional enhancer factor-3 (TEF-3), is a nuclear transcriptional factor with a potent effect on cardiovascular diseases, apart from its oncogenic role in the canonical Hippo pathway. However, the role and mechanism of RTEF-1 in VC, particularly in calcification of VSMCs, are poorly understood. Our results showed that RTEF-1 was reduced in calcified VSMCs. RTEF-1 significantly ameliorated β-glycerophosphate (β-GP)-induced VSMCs calcification, as detected by alizarin red staining and calcium content assay. Also, RTEF-1 reduced alkaline phosphatase (ALP) activity and decreased expressions of osteoblast markers such as Osteocalcin and Runt-related transcription factor-2 (Runx2), but increased expression of contractile protein, including SM α-actin (α-SMA). Additionally, RTEF-1 inhibited β-GP-activated Wnt/β-catenin pathway which plays a critical role in calcification and osteogenic differentiation of VSMCs. Specifically, RTEF-1 reduced the levels of Wnt3a, p-β-catenin (Ser675), glycogen synthase kinase-3β (GSK-3β), and p-GSK-3β (Ser9), but increased the levels of p-β-catenin (Ser33/37). Also, RTEF-1 increased the ratio of p-β-catenin (Ser33/37) to β-catenin proteins and decreased the ratio of p-GSK-3β (Ser9) to GSK-3β protein. LiCl, a Wnt/β-catenin signaling activator, was observed to reverse the protective effect of RTEF-1 overexpression on VSMCs calcification induced by β-GP. Accordingly, Dickkopf-1 (Dkk1), a Wnt antagonist, attenuated the role of RTEF-1 deficiency in β-GP-induced VSMCs calcification. Taken together, we concluded that RTEF-1 ameliorated β-GP-induced calcification and osteoblastic differentiation of VSMCs by inhibiting Wnt/β-catenin signaling pathway.


2021 ◽  
Vol 12 (8) ◽  
Author(s):  
Hanyue Chang ◽  
Qiaoshi Xu ◽  
Jiayi Li ◽  
Mingyu Li ◽  
Zhiyuan Zhang ◽  
...  

AbstractPyruvate kinase M2 as a key rate-limiting enzyme in glycolysis, it plays a critical role in metabolic reprogramming and carcinogenesis. However, whether PKM2 can promote immunosuppressive microenvironment formation remains unknown in head and neck squamous cell carcinoma (HNSCC). PKM2 expression was detected using immunohistochemical staining. The biological functions of PKM2 were investigated in vitro and in vivo. Lactate production and the expression of Galectin-9, a critical immunosuppression molecule, were detected after PKM2 knockdown and overexpression in HNSCC cells. The mechanism of lactate regulating Galectin-9 expression through NF-κB signaling was explored in vitro. Overexpression of PKM2 correlates with poor prognosis in HNSCC patients. Silencing PKM2 markedly inhibits proliferation and metastasis capacity in vivo and in vitro, and vice versa. The glycolysis and glycolytic capacity are significantly decreased after PKM2 silencing. Lactate secretion induced by PKM2 significantly promotes migration and invasion capacity. Furthermore, a positive correlation between PKM2 and Galectin-9 expression is observed in HNSCC tissues. The induction of Galectin-9 expression by PKM2 can be affected by a lactate transporter inhibitor. Mechanically, lactate impeded the suppressive transcriptional complex formation of NF-κB and histone deacetylase 3 (HDAC3), which released the transcription of Galectin-9 mediated by NF-κB signaling. Our findings demonstrate that lactate produced by PKM2 upregulation promotes tumor progression and Galectin-9-mediated immunosuppression via NF-κB signaling inhibition in HNSCC, which bridges metabolism and immunosuppression. The novel PKM2-lactate-Galectin-9 axis might be a potential therapeutic target in HNSCC.


Endocrinology ◽  
2013 ◽  
Vol 154 (1) ◽  
pp. 388-399 ◽  
Author(s):  
Youli Hu ◽  
Subathra Poopalasundaram ◽  
Anthony Graham ◽  
Pierre-Marc Bouloux

Fibroblast growth factor (FGF) signaling is essential for both olfactory bulb (OB) morphogenesis and the specification, migration, and maturation of the GnRH-secreting neurons. Disruption of FGF signaling contributes to Kallmann syndrome characterized by both anosmia and sexual immaturity. However, several unanswered questions remain as to which specific FGF receptor (FGFR)-1 signaling pathways are necessary for OB and GnRH neuronal development. Here, using pharmacological phosphatidylinositol 3-kinase (PI3K) isoform-specific inhibitors, we demonstrate a central role for the PI3K p110α isoform as a downstream effector of FGFR1 signaling for both GnRH neuronal migration and OB development. We show that signaling via the PI3K p110α isoform is required for GnRH neuronal migration in explant cultures of embryonic day (E) 4 chick olfactory placodes. We also show that in ovo administration of LY294002, a global PI3K inhibitor as well as an inhibitor to the PI3K p110α isoform into the olfactory placode of E3 chick embryo impairs GnRH neuronal migration toward the forebrain. In contrast, in ovo PI3K inhibitor treatment produced no obvious defects on primary olfactory sensory neuron axonal targeting and bundle formation. We also demonstrate that anosmin-1 and FGF2 induced neuronal migration of immortalized human embryonic GnRH neuroblast cells (FNC-B4-hTERT) is mediated by modulating FGFR1 signaling via the PI3K p110α isoform, specifically through phosphorylation of the PI3K downstream effectors, Akt and glycogen synthase kinase-3β. Finally, we show that neurite outgrowth and elongation of OB neurons in E10 chick OB explants are also dependent on the PI3K p110α isoform downstream of FGFR1. This study provides mechanistic insight into the etiology of Kallmann syndrome.


2018 ◽  
Vol 47 (1) ◽  
pp. 89-100 ◽  
Author(s):  
Sameera Iqbal ◽  
Mina Ghanimi Fard ◽  
Arun Everest-Dass ◽  
Nicolle H. Packer ◽  
Lindsay M. Parker

Abstract Glycosylation, the enzymatic process by which glycans are attached to proteins and lipids, is the most abundant and functionally important type of post-translational modification associated with brain development, neurodegenerative disorders, psychopathologies and brain cancers. Glycan structures are diverse and complex; however, they have been detected and targeted in the central nervous system (CNS) by various immunohistochemical detection methods using glycan-binding proteins such as anti-glycan antibodies or lectins and/or characterized with analytical techniques such as chromatography and mass spectrometry. The glycan structures on glycoproteins and glycolipids expressed in neural stem cells play key roles in neural development, biological processes and CNS maintenance, such as cell adhesion, signal transduction, molecular trafficking and differentiation. This brief review will highlight some of the important findings on differential glycan expression across stages of CNS cell differentiation and in pathological disorders and diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease, multiple sclerosis, amyotrophic lateral sclerosis, schizophrenia and brain cancer.


2021 ◽  
Author(s):  
Yi-Jun Wang ◽  
Matthew A. Downey ◽  
Sungwoon Choi ◽  
Timothy M. Shoup ◽  
David R. Elmaleh

Abstract Neurodegenerative diseases are characterized by chronic neuroinflammation and may perpetuate ongoing fibrotic reactions within the central nervous system. In this report, RNA-seq analysis shows that administration of the pro-inflammatory cytokine TNF-α to HMC3 human microglia results in a robust upregulation of fibrosis-associated genes. Subsequent treatment with cromolyn and its fluorinated analogue F-cromolyn resulted in reduced secretion of collagen XVIII, fibronectin, and tenascin-c. Additionally, we show that cromolyn and F-cromolyn reduce secretion of pro-inflammatory proteins PLP1, PELP1, HSP90, IL-2, GRO-α, Eotaxin, and VEGF-Α, while promoting secretion of anti-inflammatory IL-4 in HMC3 microglia. Neurite outgrowth in PC12 neuronal cells is augmented by cromolyn and F-cromolyn in concert with nerve growth factor. Treatment also differentially altered secretion of neurogenesis-related proteins TTL, PROX1, Rab35, and CSDE1 in HMC3 microglia. Finally, iPSC-derived human microglia more readily phagocytose Aβ42 with cromolyn and F-cromolyn relative to controls. We propose the cromolyn platform targets multiple proteins upstream of PI3K/Akt/mTOR, NF-κB, and GSK-3β signaling pathways to affect cytokine, chemokine, and fibrosis-related protein expression.


2021 ◽  
Author(s):  
Bashaer Abu Khatir ◽  
Gordon Omar Davis ◽  
Mariam Sameem ◽  
Rutu Patel ◽  
Jackie Fong ◽  
...  

Tuberin is a member of a large protein complex, Tuberous Sclerosis Complex, and acts as a sensor for nutrient status regulating protein synthesis and cell cycle progression. Mutations in the Tuberin gene, TSC2, lead to the formation of tumors and developmental defects in many organ systems, including the central nervous system. Tuberin is expressed in the brain throughout development and levels of Tuberin have been found to decrease during neuronal differentiation in cell lines in vitro. Our current work investigates the levels of Tuberin at two stages of embryonic development in vivo, and we study the mRNA and protein levels during a time course using immortalized cell lines in vitro. Our results show that Tuberin levels remain stable in the olfactory bulb but decrease in the Purkinje cell layer during embryonic mouse brain development. We show here that Tuberin levels are higher when cells are cultured as neurospheres, and knockdown of Tuberin results in a reduction in the number of neurospheres. These data provide support for the hypothesis that Tuberin is an important regulator of stemness and the reduction of Tuberin levels might support functional differentiation in the central nervous system. Understanding how Tuberin expression is regulated throughout neural development is essential to fully comprehend the role of this protein in several developmental and neural pathologies.


Biomolecules ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 25
Author(s):  
Marta R. Casanova ◽  
Rui L. Reis ◽  
Albino Martins ◽  
Nuno M. Neves

Peripheral nerve injury still remains a major clinical challenge, since the available solutions lead to dysfunctional nerve regeneration. Even though autologous nerve grafts are the gold standard, tissue engineered nerve guidance grafts are valid alternatives. Nerve growth factor (NGF) is the most potent neurotrophic factor. The development of a nerve guidance graft able to locally potentiate the interaction between injured neurons and autologous NGF would be a safer and more effective alternative to grafts that just release NGF. Herein, a biofunctional electrospun fibrous mesh (eFM) was developed through the selective retrieval of NGF from rat blood plasma. The neurite outgrowth induced by the eFM-NGF systems was assessed by culturing rat pheochromocytoma (PC12) cells for 7 days, without medium supplementation. The biological results showed that this NGF delivery system stimulates neuronal differentiation, enhancing the neurite growth more than the control condition.


1995 ◽  
Vol 130 (3) ◽  
pp. 701-710 ◽  
Author(s):  
M D Mark ◽  
Y Liu ◽  
S T Wong ◽  
T R Hinds ◽  
D R Storm

MAP kinase activity is necessary for growth factor induction of neurite outgrowth in PC12 cells. Although NGF and EGF both stimulate MAP kinase activity, EGF does not stimulate neurite extension. We report that EGF, in combination with KCl, stimulates neurite outgrowth in PC12 cells. This phenomenon was independent of intracellular Ca2+ increases and not due to enhancement of MAP kinase activity over that seen with EGF alone. However, EGF plus KCl increased intracellular cAMP, and other cAMP elevating agents acted synergistically with EGF to promote neurite outgrowth. Stimulation of neurite outgrowth by cAMP and EGF was blocked by inhibitors of transcription suggesting that synergistic regulation of transcription by the cAMP and MAP kinase pathways may stimulate neurite growth.


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