Inositol Pyrophosphate Metabolism Regulates Presynaptic Vesicle Cycling at Central Synapses

AbstractNeural networks are required to meet significant metabolic demands associated with performing sophisticated computational tasks in the brain. The necessity for efficient transmission of information imposes stringent constraints on the metabolic pathways that can be used for energy generation at the synapse, and thus low availability of energetic substrates can reduce the efficacy of synaptic function. Here we study the effects of energetic substrate availability on global neural network behavior and find that glucose alone can sustain excitatory neurotransmission required to generate high-frequency synchronous bursting that emerges in culture. In contrast, obligatory oxidative energetic substrates such as lactate and pyruvate are unable to substitute for glucose, indicating that processes involving glucose metabolism form the primary energy-generating pathways supporting coordinated network activity. Our experimental results are discussed in the context of the role that metabolism plays in supporting the performance of individual synapses, including the relative contributions from postsynaptic responses, astrocytes, and presynaptic vesicle cycling. We propose a simple computational model for our excitatory cultures that accurately captures the inability of metabolically compromised synapses to sustain synchronous bursting when extracellular glucose is depleted.

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Faculty Opinions recommendation of Cannabinoid- and lysophosphatidylinositol-sensitive receptor GPR55 boosts neurotransmitter release at central synapses.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.717992219.793473586 ◽

2013 ◽

Author(s):

Andreas Zimmer

Keyword(s):

Neurotransmitter Release ◽

Central Synapses

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Faculty Opinions recommendation of Mitochondrial support of persistent presynaptic vesicle mobilization with age-dependent synaptic growth after LTP.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.727122855.793536779 ◽

2017 ◽

Author(s):

Ege Kavalali

Keyword(s):

Synaptic Growth ◽

Age Dependent ◽

Presynaptic Vesicle

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InsP7is a small-molecule regulator of NUDT3-mediated mRNA decapping and processing-body dynamics

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1922284117 ◽

2020 ◽

Vol 117 (32) ◽

pp. 19245-19253 ◽

Cited By ~ 1

Author(s):

Soumyadip Sahu ◽

Zhenzhen Wang ◽

Xinfu Jiao ◽

Chunfang Gu ◽

Nikolaus Jork ◽

...

Keyword(s):

Stress Responses ◽

Messenger Rna ◽

Control Process ◽

Stem Cell Differentiation ◽

Wild Type ◽

Inositol Pyrophosphate ◽

Body Dynamics ◽

Processing Body ◽

The Stability

Regulation of enzymatic 5′ decapping of messenger RNA (mRNA), which normally commits transcripts to their destruction, has the capacity to dynamically reshape the transcriptome. For example, protection from 5′ decapping promotes accumulation of mRNAs into processing (P) bodies—membraneless, biomolecular condensates. Such compartmentalization of mRNAs temporarily removes them from the translatable pool; these repressed transcripts are stabilized and stored until P-body dissolution permits transcript reentry into the cytosol. Here, we describe regulation of mRNA stability and P-body dynamics by the inositol pyrophosphate signaling molecule 5-InsP7(5-diphosphoinositol pentakisphosphate). First, we demonstrate 5-InsP7inhibits decapping by recombinant NUDT3 (Nudix [nucleoside diphosphate linked moiety X]-type hydrolase 3) in vitro. Next, in intact HEK293 and HCT116 cells, we monitored the stability of a cadre of NUDT3 mRNA substrates following CRISPR-Cas9 knockout ofPPIP5Ks(diphosphoinositol pentakisphosphate 5-kinases type 1 and 2, i.e.,PPIP5KKO), which elevates cellular 5-InsP7levels by two- to threefold (i.e., within the physiological rheostatic range). ThePPIP5KKO cells exhibited elevated levels of NUDT3 mRNA substrates and increased P-body abundance. Pharmacological and genetic attenuation of 5-InsP7synthesis in the KO background reverted both NUDT3 mRNA substrate levels and P-body counts to those of wild-type cells. Furthermore, liposomal delivery of a metabolically resistant 5-InsP7analog into wild-type cells elevated levels of NUDT3 mRNA substrates and raised P-body abundance. In the context that cellular 5-InsP7levels normally fluctuate in response to changes in the bioenergetic environment, regulation of mRNA structure by this inositol pyrophosphate represents an epitranscriptomic control process. The associated impact on P-body dynamics has relevance to regulation of stem cell differentiation, stress responses, and, potentially, amelioration of neurodegenerative diseases and aging.

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AZP2006, a new promising treatment for Alzheimer’s and related diseases

Scientific Reports ◽

10.1038/s41598-021-94708-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

N. Callizot ◽

C. Estrella ◽

S. Burlet ◽

A. Henriques ◽

C. Brantis ◽

...

Keyword(s):

Therapeutic Application ◽

Neuroprotective Effects ◽

Beneficial Effects ◽

Potential Therapeutic Application ◽

Promising Treatment ◽

Central Synapses ◽

First Time ◽

Pgrn Level

AbstractProgranulin (PGRN) is a protein with multiple functions including the regulation of neuroinflammation, neuronal survival, neurite and synapsis growth. Although the mechanisms of action of PGRN are currently unknown, its potential therapeutic application in treating neurodegenerative diseases is huge. Thus, strategies to increase PGRN levels in patients could provide an effective treatment. In the present study, we investigated the effects of AZP2006, a lysotropic molecule now in phase 2a clinical trial in Progressive Supranuclear Palsy patients, for its ability to increase PGRN level and promote neuroprotection. We showed for the first time the in vitro and in vivo neuroprotective effects of AZP2006 in neurons injured with Aβ1–42 and in two different pathological animal models of Alzheimer’s disease (AD) and aging. Thus, the chronic treatment with AZP2006 was shown to reduce the loss of central synapses and neurons but also to dramatically decrease the massive neuroinflammation associated with the animal pathology. A deeper investigation showed that the beneficial effects of AZP2006 were associated with PGRN production. Also, AZP2006 binds to PSAP (the cofactor of PGRN) and inhibits TLR9 receptors normally responsible for proinflammation when activated. Altogether, these results showed the high potential of AZP2006 as a new putative treatment for AD and related diseases.

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