NPTX1 Mediates the Facilitating Effects of Hypoxia-Stimulated Human Adipocytes on Adipose-Derived Stem Cell Activation and Autologous Adipose Graft Survival Rate.

BACKGROUND: Autologous adipose tissue is an ideal material for soft tissue filling and transplantation; however, high volumes of fat absorption over time lead to a relatively low overall survival percentage. The survival and differentiation of adipose-derived stem cells (ADSCs) in the transplanted microenvironment might improve adipose graft survival. Adipocytes have been reported to affect ADSC activation. However, its underlying mechanisms remain unclear. METHODS: Human ADSCs were incubated in a culture medium supplemented with hypoxic or normoxic conditioned culture medium (CM) derived from human adipocytes. Neuronal Pentraxin 1 (NPTX1) was overexpressed or knocked down in human adipocytes using an overexpression vector (NPTX1 OE) or small interfering RNA (siRNA) transfection, respectively. ADSC differentiation and paracrine secretion were assessed. Nude mice were implanted with human adipocytes and ADSCs. The adipose tissue was subsequently evaluated by histological analysis. RESULTS: CM from hypoxic-stimulated human adipocytes significantly facilitated the differentiation ability and paracrine levels of ADSCs. NPTX1 was significantly up-regulated in human adipocytes exposed to hypoxic conditions. In vitro, CM derived from hypoxia-stimulated human adipocytes or NPTX1-overexpressing human adipocytes exposed to normoxia promoted ADSC differentiation and paracrine; after silencing NPTX1, the facilitating effects of hypoxia-treated human adipocytes on ADSC activation were eliminated. Similarly, in vivo, the NPTX1 OE + normoxia-CM group saw improved histological morphology and fat integrity, less fibrosis and inflammation, and increased vessel numbers compared with the OE NC + normoxia-CM group; the adipocyte grafts of the si-NC + hypoxia-CM group yielded the most improved histological morphology, fat integrity, and the most vessel numbers. However, these enhancements of ADSC activation and adipose graft survival were partially abolished by NPTX1 knockdown in human adipocytes. CONCLUSION: NPTX1 might mediate the facilitating effects of hypoxia-stimulated human adipocytes on ADSC activation, thereby improving adipose tissue survival rate after autologous fat transplantation and the effectiveness of autologous fat transplantation through promoting ADSC activation. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

miR-148a-3p regulates proliferation and apoptosis of idiopathic gingival fibroma by targeting NPTX1.

OBJECTIVE: Idiopathic gingival fibromatosis (IGF) is a rare heterogeneous disease that results in the progressive and diffuse hyperplasia of gingival tissues. MicroRNAs are implicated in the development and progression of various tumors. The present study aimed to explore the potential roles and mechanisms of miR-148a-3p in IGF. METHODS: Gingival fibroblasts (GFs) were transfected with miR-148a-3p mimics, miR-148a-3p inhibitors, or siNPTX1, and then, the proliferation and apoptosis of GFs and the expression of related genes were evaluated using Cell Counting Kit-8 assays, 5-ethynyl-2'-deoxyuridine assays, flow cytometry, reverse transcription-quantitative polymerase chain reaction, and western blot analysis, respectively. RESULTS: miR-148a-3p was highly expressed in GFs of IGF (IGF-GFs) as compared with normal GFs (N-GFs). Overexpression of miR-148a-3p promoted the proliferation and inhibited the apoptosis of N-GFs, whereas downregulation of miR-148a-3p had the opposite effect in IGF-GFs. Knockdown of NPTX1 reversed miR-148a-3p-mediated effects in IGF-GFs. Dual-luciferase reporter assay confirmed that NPTX1 is a direct target of miR-148a-3p. CONCLUSION: These findings identify that miR-148a-3p could regulate cell proliferation and apoptosis by targeting NPTX1, providing new insights for the further study of the molecular mechanism and treatment of IGF.

C1QL3 promotes cell-cell adhesion by mediating complex formation between ADGRB3/BAI3 and neuronal pentraxins.

Synapses are the fundamental structural unit by which neurons communicate. An orchestra of proteins regulates diverse synaptic functions, including synapse formation, maintenance, and elimination-synapse homeostasis. Some proteins of the larger C1q super-family are synaptic organizers involved in crucial neuronal processes in various brain regions. C1Q-like (C1QL) proteins bind to the adhesion G protein-coupled receptor B3 (ADGRB3) and act at synapses in a subset of circuits. To investigate the hypothesis that the secreted C1QL proteins mediate tripartite trans-synaptic adhesion complexes, we conducted an in vivo interactome study and identified new binding candidates. We demonstrate that C1QL3 mediates a novel cell-cell adhesion complex involving ADGRB3 and two neuronal pentraxins, NPTX1 and NPTXR. Analysis of single-cell RNA-Seq data from the cerebral cortex shows that C1ql3, Nptx1, and Nptxr are highly co-expressed in the same excitatory neurons. Thus, our results suggest the possibility that in vivo the three co-expressed proteins are presynaptically secreted and form a complex capable of binding to postsynaptically localized ADGRB3, thereby creating a novel trans-synaptic adhesion complex. Identifying new binding partners for C1QL proteins and deciphering their underlying molecular principles will accelerate our understanding of their role in synapse organization.

miR-139-5p mediates the palmitate-induced inhibition of insulin secretion by targeting neuronal pentraxin 1 in INS-1 cells.

High fatty acid reduces insulin secretion in pancreatic ß-cells and miR-139-5p is increased in diabetic pancreatic tissues and induces islet ß-cell apoptosis. However, to date, there is no study exploring whether or not miR-139-5p is involved in high fatty acid-induced insulin secretion. In the present study, INS-1 cells were exposed to different concentrations (0.1, 0.2, and 0.4 mM) of palmitate for different time periods (12, 24, and 48 h). The expression levels of miR-139-5p and neuronal pentraxin 1 (NPTX1) were evaluated by real-time PCR and western blot analysis. The regulation of NPTX1 by miR-139-5p was examined by luciferase assay. Cell transfection was conducted using Lipo8000 or Lipofectamine RNAiMAX. Potassium or glucose-stimulated insulin secretion levels were used to verify the function of miR-139-5p or NPTX1 in insulin secretion. Insulin secretion levels were detected by radioimmunoassay. We found that miR-139-5p was increased in INS-1 cells stimulated with palmitate. In addition, miR-139-5p was also elevated in islets of high-fat diet-fed mice and db/db mice compared to those in islets of normal diet-fed mice and wild-type mice. Knockdown of miR-139-5p could reverse high fatty acid-induced insulin secretion defects in INS-1 cells. Furthermore, we demonstrated that NPTX1 is a target of miR-139-5p. miR-139-5p mediated palmitate-induced insulin secretion defects by targeting NPTX1. Moreover, palmitate treatment declined the expression of NPTX1 and the NPTX1 expression was also decreased in islets of high-fat diet-fed mice and db/db mice. Impaired NPTX1 expression is involved in fatty acid-induced insulin secretion defects. Collectively, our results illustrate that the induction of ß-cell insulin secretion defects by fatty acids is mediated, at least in part, by miR-139-5p via downregulation of NPTX1 expression.

Urban air particulate matter induces mitochondrial dysfunction in human olfactory mucosal cells.

BACKGROUND: The adverse effects of air pollutants including particulate matter (PM) on the central nervous system is increasingly reported by epidemiological, animal and post-mortem studies in the last decade. Oxidative stress and inflammation are key consequences of exposure to PM although little is known of the exact mechanism. The association of PM exposure with deteriorating brain health is speculated to be driven by PM entry via the olfactory system. How air pollutants affect this key entry site remains elusive. In this study, we investigated effects of urban size-segregated PM on a novel cellular model: primary human olfactory mucosal (hOM) cells. RESULTS: Metabolic activity was reduced following 24-h exposure to PM without evident signs of toxicity. Results from cytometric bead array suggested a mild inflammatory response to PM exposure. We observed increased oxidative stress and caspase-3/7 activity as well as perturbed mitochondrial membrane potential in PM-exposed cells. Mitochondrial dysfunction was further verified by a decrease in mitochondria-dependent respiration. Transient suppression of the mitochondria-targeted gene, neuronal pentraxin 1 (NPTX1), was carried out, after being identified to be up-regulated in PM2.5-1 treated cells via RNA sequencing. Suppression of NPTX1 in cells exposed to PM did not restore mitochondrial defects resulting from PM exposure. In contrast, PM-induced adverse effects were magnified in the absence of NPTX1, indicating a critical role of this protein in protection against PM effects in hOM cells. CONCLUSION: Key mitochondrial functions were perturbed by urban PM exposure in a physiologically relevant cellular model via a mechanism involving NPTX1. In addition, inflammatory response and early signs of apoptosis accompanied mitochondrial dysfunction during exposure to PM. Findings from this study contribute to increased understanding of harmful PM effects on human health and may provide information to support mitigation strategies targeted at air pollution.

NPTX1 inhibits colon cancer cell proliferation through down-regulating cyclin A2 and CDK2 expression.

Colon cancer is the third most common malignancy and one of the leading causes of cancer-associated mortality worldwide. Neuronal pentraxin 1 (NPTX1) is associated with tumor progression in some types of tumors. However, its expression and role in colon cancer has not been yet reported. Here we observed that NPTX1 was down-regulated in colon cancer. Additionally, we explored the functional significance of NPTX1 in colon cancer. We found that over-expression of NPTX1 inhibited colon cancer cell growth by performing MTT, colony formation, Edu corporation assays, and cell cycle analysis. In vivo mouse experiments also confirmed the anti-proliferative role of NPTX1 in colon cancer. Further mechanistic study showed that over-expression of NPTX1 inhibited the expression of cyclin A2 and CDK2 in colon cancer cells, thereby regulating the Rb-E2F signaling. In summary, these findings reveal that NPTX1 suppress the colon cancer cell growth and might serve as a useful potential target for treatment of colon cancer.

NPTX1 is a novel epigenetic regulation gene and associated with prognosis in lung cancer.

BACKGROUND: CpG island hypermethylation of gene promoters is a well-known mechanism of epigenetic regulation of tumor related-genes and is directly linked to lung carcinogenesis. Alterations in the pattern of methylation of the NPTX1 gene have not yet been studied in detail in human lung cancer. METHODS: Methylation-specific PCR (MSP) and bisulfite sequencing PCR (BSP) were used to analyze promoter methylation status, and real-time quantitative reverse transcription-PCR (qRT-PCR) examined mRNA levels. Subsequently, we compared the methylation profile of NPTX1 in samples of neoplastic and non-neoplastic lung tissue taken from the same patients by using quantitative methylation specific PCR (QMSP). RESULTS: CpG island hypermethylation in promoter of NPTX1 was confirmed in lung cancer cell lines. A significant increase in NPTX1 methylation was identified in lung cancer specimens compared to adjacent noncancerous tissues and that it was negatively correlated with its mRNA expression. The overall survival time among patients carrying methylated NPTX1 tumors was significantly shorter as compared to those with unmethylated NPTX1 tumors (P = 0.011). Moreover, methylation of NPTX1 gene was found to be an independent prognostic factor for poor overall survival based on multivariate analysis models (p = 0.021), as was age ≥60 years old (p = 0.012) and TNM stage (p < 0.001). CONCLUSIONS: These results suggest that NPTX1 hypermethylation and consequent mRNA changes might be an important molecular mechanism in lung cancer. Epigenetic alterations in NPTX1 may serve as potential diagnostic and prognostic biomarkers in lung cancer.

Analysis of t(9;17)(q33.2;q25.3) chromosomal breakpoint regions and genetic association reveals novel candidate genes for bipolar disorder.

OBJECTIVES: Breakpoints of chromosomal abnormalities facilitate identification of novel candidate genes for psychiatric disorders. Genome-wide significant evidence supports the linkage between chromosome 17q25.3 and bipolar disorder (BD). Co-segregation of translocation t(9;17)(q33.2;q25.3) with psychiatric disorders has been reported. We aimed to narrow down these chromosomal breakpoint regions and to investigate the associations between single nucleotide polymorphisms within these regions and BD as well as schizophrenia (SZ) in large genome-wide association study samples. METHODS: We cross-linked Danish psychiatric and cytogenetic case registers to identify an individual with both t(9;17)(q33.2;q25.3) and BD. Fluorescent in situ hybridization was employed to map the chromosomal breakpoint regions of this proband. We accessed the Psychiatric Genomics Consortium BD (n = 16,731) and SZ (n = 21,856) data. Genetic associations between these disorders and single nucleotide polymorphisms within these breakpoint regions were analysed by BioQ, FORGE, and RegulomeDB programmes. RESULTS: Four protein-coding genes [coding for (endonuclease V (ENDOV), neuronal pentraxin I (NPTX1), ring finger protein 213 (RNF213), and regulatory-associated protein of mammalian target of rapamycin (mTOR) (RPTOR)] were found to be located within the 17q25.3 breakpoint region. NPTX1 was significantly associated with BD (p = 0.004), while ENDOV was significantly associated with SZ (p = 0.0075) after Bonferroni correction. CONCLUSIONS: Prior linkage evidence and our findings suggest NPTX1 as a novel candidate gene for BD.

Plasma Biomarkers in Neurodegenerative Dementias: Unrevealing the Potential of Serum Oxytocin, BDNF, NPTX1, TREM2, TNF-alpha, IL-1, and Prolactin.

BACKGROUND: Dementia encompasses a range of neurodegenerative disorders characterized by cognitive decline and functional impairment. The identification of reliable biomarkers is essential for accurate diagnosis and gaining insights into the mechanisms underlying diseases. OBJECTIVE: This study aimed to investigate the plasma biomarker profiles associated with Brain- Derived Neurotrophic Factor (BDNF), Oxytocin, Neuronal Pentraxin-1 (NPTX1), Triggering Receptor Expressed on Myeloid Cells 2 (TREM2), Tumor Necrosis Factor-alpha (TNF-alpha), Interleukin- 1 (IL-1), and Prolactin in Alzheimer's disease (AD), dementia with Lewy bodies (DLB), frontotemporal dementias (FTD), and healthy controls. METHODS: Serum levels of the aforementioned biomarkers were analyzed in 23 AD, 28 DLB, 15 FTD patients recruited from outpatient units, and 22 healthy controls. Diagnostic evaluations followed established criteria, and standardized clinical tests were conducted. Blood samples were collected and analyzed using ELISA and electrochemiluminescence immunoassay methods. RESULTS: Serum BDNF and oxytocin levels did not significantly differ across groups. NPTX1, TREM2, TNF-alpha, and IL-1 levels also did not show significant differences among dementia groups. However, prolactin levels exhibited distinct patterns, with lower levels in male DLB patients and higher levels in female AD patients compared to controls. CONCLUSION: The study findings suggest potential shared mechanisms in dementia pathophysiology and highlight the importance of exploring neuroendocrine responses, particularly in AD and DLB. However, further research is warranted to elucidate the role of these biomarkers in dementia diagnosis and disease progression.

Serum level of NPTX1 is independent of serum MKRN3 in central precocious puberty.

OBJECTIVES: Makorin ring finger protein 3 (MKRN3) is associated with the initiation of puberty, and loss of function mutation of MKRN3 is the most common genetic cause of central precocious puberty (CPP). A recent study reported that MKRN3 interacts with and suppresses neural pentraxin-1 precursor (NPTX1) activity via polyubiquitination during early puberty in the mouse hypothalamus. This study investigated the correlation between serum NPTX1 and MKRN3 in CPP girls and predicted the potential role of NPTX1 in pubertal progression. METHODS: In this case-control study, we examined 34 girls diagnosed with CPP and 34 healthy prepubertal girls. Anthropometric and hormonal parameters were measured and serum levels of NPTX1 and MKRN3 were evaluated with commercial enzyme-linked immunosorbent assay kits. RESULTS: Serum MKRN3 level decreased significantly in CPP patients compared to controls (344.48 ± 333.77 and 1295.21 ± 780.80 pg/mL, respectively, p<0.001). Serum MKRN3 tended to decrease as Tanner breast stage increased. However, no significant difference was observed in serum NPTX1 levels between patients and controls (20.14 ± 31.75 ng/mL and 12.93 ± 8.28 ng/mL, respectively, p=0.248). The serum level of NPTX1 did not change significantly with the Tanner breast stage. Serum NPTX1 was correlated with the height standard deviation score (r=0.255; p<0.05), but was not correlated with serum MKRN3 level or the others. Conclusion: Although serum NPTX1 level was independent of serum MKRN3 level, the possibility they might be involved in the progression of puberty or CPP remains. Further research is needed to determine their role in the hypothalamus.

Long non coding RNA SLC26A4-AS1 exerts antiangiogenic effects in human glioma by upregulating NPTX1 via NFKB1 transcriptional factor.

Malignant gliomas are a heterogeneous group of brain tumors with a poor prognosis, which is largely due to its aggressive invasiveness and angiogenesis. In recent years, it has been found that multiple long noncoding RNAs (lncRNAs) participate in a wide range of biological functions including angiogenesis through the regulation of gene expression in cancers. In this study, we investigate and report the novel role of lncRNA SLC26A4-AS1 in gliomas, with a novel mechanism involving transcription factors NFKB1 and NPTX1. We determined that SLC26A4-AS1 was downregulated in human glioma tissues and cells. Furthermore, overexpression of SLC26A4-AS1 or NPTX1 restrained the aggressiveness of glioma cells and their pro-angiogenic ability. SLC26A4-AS1 was also found to upregulate NPTX1 by recruiting NFKB1 into the NPTX1 promoter. Moreover, silencing of either NPTX1 or NFKB1 restored the aggressive and pro-angiogenic properties of glioma cells in the presence of SLC26A4-AS1. Taken together, we demonstrate that SLC26A4-AS1 promotes NPTX1 transcriptional activity by recruiting NFKB1 and thus exerting antiangiogenic effects on glioma cells. This study provides an experimental basis for the intervention of SLC26A4-AS1 in the treatment of gliomas.

Dysregulation of Synaptic Signaling Genes Is Involved in Biology of Uterine Leiomyoma.

Uterine leiomyomas are tumors, which are hormone driven and originate from the smooth muscle layer of the uterine wall. In addition to known genes in leiomyoma pathogenesis, recent approaches also highlight epigenetic malfunctions as an important mechanism of gene dysregulation. RNA sequencing raw data from pair-matched normal myometrium and fibroid tumors from two independent studies were used as discovery and validation sets and reanalyzed. RNA extracted from normal myometrium and fibroid tumors from 58 Slovenian patients was used as independent confirmation of most significant differentially expressed genes. Subsequently, GWA data from leiomyoma patients were used in order to identify genetic variants at epigenetic marks. Gene Ontology analysis of the overlap of two independent RNA-seq analyses showed that NPTX1, NPTX2, CHRM2, DRD2 and CACNA1A were listed as significant for several enriched GO terms. All five genes were subsequently confirmed in the independent Slovenian cohort. Additional integration and functional analysis showed that genetic variants in these five gene regions are listed at a chromatin structure and state, predicting promoters, enhancers, DNase hypersensitivity and altered transcription factor binding sites. We identified a unique subgroup of dysregulated synaptic signaling genes involved in the biology and pathogenesis of leiomyomas, adding to the complexity of tumor biology.

NPTX1 promotes metastasis via integrin/FAK signaling in gastric cancer.

PURPOSE: This study aimed to investigate the effect of NPTX1 on the prognosis of gastric cancer (GC), as well as the metastatic process in GC. MATERIALS AND METHODS: The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases were used to analyze the association between NPTX1 expression and prognosis in GC. Quantitative real-time polymerase chain reaction and Western blots were applied to examine the expression of NPTX1 in GC cell lines and expression of genes in downstream pathways. The role of NPTX1 on the migration, invasion, adhesion, and proliferation of GC cell lines was investigated with the transwell assay, the adhesion assay, and the MTT assay. Immunofluorescence staining was used to observe the effect of NPTX1 knockdown on the morphology of cells. RESULTS: According to the review of TCGA and GEO databases of GC, we found that the expression of NPTX1 increased in cancer tissues and high NPTX1 expression was correlated with poor overall survival, which was associated with lymph node stage in clinicopathologic parameters. Knockdown of NPTX1 attenuated the migration, invasion, and adhesion abilities of GC cells. According to gene set enrichment analysis, NPTX1 was found to be positively related to integrin and focal adhesion (FA). Additionally, NPTX1 knockdown decreased the expression of integrin α1 and integrin α7, followed by deregulation of the expression of p-Src, p-Akt, p-Erk, MMP2, and MMP7, as well as inhibiting the formation of FA complexes and decreasing the length of pseudopods in GC cells. CONCLUSION: Our study provides strong evidence that NPTX1 plays a crucial role in promoting metastasis and acts as a prognostic indicator in GC.

Hsa_circ_0070269 inhibits hepatocellular carcinoma progression through modulating miR-182/NPTX1 axis.

Circular RNAs (circRNAs) have recently been shown to play critical roles in tumorigenesis. However, the roles of circRNAs in hepatocellular carcinoma (HCC) remain largely unknown. In the present study, we identified a novel circRNA (hsa_circ_0070269) was significantly decreased in HCC tissues and cell lines, low hsa_circ_0070269 expression was positively associated with advanced tumor stage, lymph node metastasis, and poor overall survival. Hsa_circ_0070269 overexpression suppressed proliferation and invasion of HCC cells in vitro and reduced tumor growth in vivo. Mechanistically, hsa_circ_0070269 increased NPTX1 expression via sponging miR-182 in HCC cells, which inhibited aggressive tumor behavior. Taken together, our findings suggest that hsa_circ_0070269 might play an important role in HCC development via miR-182/NPTX1 axis, therefore could serve as a potential therapeutic target for HCC treatment.

As a downstream target of the AKT pathway, NPTX1 inhibits proliferation and promotes apoptosis in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is correlated with a poor prognosis and high mortality worldwide. Neuronal pentraxin 1 (NPTX1) has been reported to play an oncogenic role in several types of tumors. However, its expression and function in HCC is not yet fully understood. In the present study, we aimed to investigate the clinicopathological significance of NPTX1 in HCC and the underlying mechanisms. We observed that the expression of NPTX1 was decreased significantly in HCC and was associated with tumor size and metastasis in patients. Gain-of-function approaches revealed that NPTX1 suppressed the growth ability of HCC cells and contributed to mitochondria- related apoptosis. Furthermore, mechanistic investigations showed that the AKT (AKT serine/threonine kinase) pathway can regulate the effects of NPTX1 in HCC cells. After blocking the AKT pathway, the action of NPTX1 was greatly increased. In summary, we demonstrated that NPTX1 inhibited growth and promoted apoptosis in HCC via an AKT-mediated signaling mechanism. These findings indicate that NPTX1 is a potential clinical therapeutic target.

Mkrn3 functions as a novel ubiquitin E3 ligase to inhibit Nptx1 during puberty initiation.

Central precocious puberty (CPP) is attributed to the disorder of some trigger factors those can activate the hypothalamic-pituitary-gonadal axis controlled by GnRH neurons. Many recent studies reveal one of those trigger factors, Makorin ring finger protein 3 (Mkrn3), whose loss-of-function mutations are implicated in CPP. Although Mkrn3 contained zinc Ring finger domain is considered as a putative E3 ubiquitin ligase, its actual function is never reported. Here, our results demonstrated that in mice hypothalamus before and when puberty initiated, Mkrn3 expressed the reversed tendency with Nptx1, which is an important secreted protein for neuron development. Furthermore, our data manifested that Mkrn3 interacted and suppressed Nptx1 activity. And the Ring finger domain of Mkrn3 contained was determined to be essential for binding with Nptx1 for its polyubiquitination during the puberty initiation. Our study shed light on the molecular insights into the function of Mkrn3 in the events of puberty initiation.

An Intrinsic Transcriptional Program Underlying Synaptic Scaling during Activity Suppression.

Homeostatic scaling allows neurons to maintain stable activity patterns by globally altering their synaptic strength in response to changing activity levels. Suppression of activity by the blocking of action potentials increases synaptic strength through an upregulation of surface α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. Although this synaptic upscaling was shown to require transcription, the molecular nature of the intrinsic transcription program underlying this process and its functional significance have been unclear. Using RNA-seq, we identified 73 genes that were specifically upregulated in response to activity suppression. In particular, Neuronal pentraxin-1 (Nptx1) increased within 6 hr of activity blockade, and knockdown of this gene blocked the increase in synaptic strength. Nptx1 induction is mediated by calcium influx through the T-type voltage-gated calcium channel, as well as two transcription factors, SRF and ELK1. Altogether, these results uncover a transcriptional program that specifically operates when neuronal activity is suppressed to globally coordinate the increase in synaptic strength.