Neuronal Pentraxin Research Articles

The neuronal pentraxin receptor (NPTXR) as a candidate biomarker of synaptic dysfunction in mild cognitive impairment

AbstractBackgroundEarly deficits of cognitive symptoms have molecular background closely related to Alzheimer’s Disease (AD). Before developing full‐blown AD, mild cognitive impairment (MCI) develops. It has been suggested that synaptic pathology is closely associated with memory impairment in the early phase of the disease and may be monitored by assessment of the synaptic proteins in cerebrospinal fluid (CSF), like neuronal pentraxin receptor (NPTXR). The highest expression of NPTXR and involvement in neuronal processes have been observed in the hippocampus and cortex. This candidate biomarker of synaptic dysfunction may have a crucial role in synaptic transmission and modulation of memory processes with other synaptic proteins. The purpose of the our investigation was to assessed the neuronal pentraxin receptor (NPTXR) level in cerebrospinal fluid (CSF) in MCI patients.MethodThe study included 17 patients with MCI and 17 non‐demented controls. The CSF levels of NPTXR and classical AD biomarkers, such as Aβ‐42, Aβ‐42/Aβ‐40, Tau, and pTau181, were assessed by commercially available immunoenzyme assays.ResultThe CSF concentration of NPTXR was significantly lower in MCI patients compared to non‐demented controls. Moreover, NPTXR level was positively correlated with Tau181, Aβ‐42, and total Tau proteins in MCI patients.ConclusionOur results suggest that Neuronal Pentraxin Receptor may be one of the biomarker reflecting synaptic dysfunction in MCI patients. These preliminary results seem very promising, particularly for the early diagnosis of Alzheimer’s disease. Future research concerning NPTXR is necessary to understand better the role of the protein in early pathological processes of the disease.

The neuronal pentraxin Nptx2 regulates complement activity and restrains microglia-mediated synapse loss in neurodegeneration.

Complement overactivation mediates microglial synapse elimination in neurological diseases such as Alzheimer's disease (AD) and frontotemporal dementia (FTD), but how complement activity is regulated in the brain remains largely unknown. We identified that the secreted neuronal pentraxin Nptx2 binds complement C1q and thereby regulates its activity in the brain. Nptx2-deficient mice show increased complement activity, C1q-dependent microglial synapse engulfment, and loss of excitatory synapses. In a neuroinflammation culture model and in aged TauP301S mice, adeno-associated virus (AAV)-mediated neuronal overexpression of Nptx2 was sufficient to restrain complement activity and ameliorate microglia-mediated synapse loss. Analysis of human cerebrospinal fluid (CSF) samples from a genetic FTD cohort revealed reduced concentrations of Nptx2 and Nptx2-C1q protein complexes in symptomatic patients, which correlated with elevated C1q and activated C3. Together, these results show that Nptx2 regulates complement activity and microglial synapse elimination in the brain and that diminished Nptx2 concentrations might exacerbate complement-mediated neurodegeneration in patients with FTD.

Synaptic biomarkers in the cerebrospinal fluid associate differentially with classical neuronal biomarkers in patients with Alzheimer’s disease and frontotemporal dementia

BackgroundLoss of synaptic functionality has been recently identified as an early-stage indicator of neurological diseases. Consequently, monitoring changes in synaptic protein levels may be relevant for observing disease evolution or treatment responses in patients. Here, we have studied the relationship between fluid biomarkers of neurodegeneration and synaptic dysfunction in patients with Alzheimer’s disease (AD), frontotemporal dementia (FTD), and subjective cognitive decline (SCD).MethodsThe exploratory cohort consisted of cerebrospinal fluid (CSF) samples (n = 60) from patients diagnosed with AD (n = 20), FTD (n = 20), and SCD (n = 20) from the Amsterdam Dementia Cohort. We developed two novel immunoassays for the synaptic proteins synaptosomal-associated protein-25 (SNAP25) and vesicle-associated membrane protein-2 (VAMP2). We measured the levels of these biomarkers in CSF, in addition to neuronal pentraxin-2 (NPTX2), glutamate ionotropic receptor-4 (GluR4), and neurogranin (Ng) for this cohort. All in-house immunoassays were validated and analytically qualified prior to clinical application. CSF neurogranin (Ng) was measured using a commercially available ELISA.ResultsThis pilot study indicated that SNAP25, VAMP2, and Ng may not be specific biomarkers for AD as their levels were significantly elevated in patients with both AD and FTD compared to SCD. Moreover, the strength of the correlations between synaptic proteins was lower in the AD and FTD clinical groups compared to SCD. SNAP25, VAMP2, and Ng correlated strongly with each other as well as with total Tau (Tau) and phosphorylated Tau (PTau) in all three clinical groups. However, this correlation was weakened or absent with NPTX2 and GluR4. None of the synaptic proteins correlated to neurofilament light (NfL) in any clinical group.ConclusionThe correlation of the synaptic biomarkers with CSF Tau and PTau but the lack thereof with NfL implies that distinct pathological pathways may be involved in synaptic versus axonal degeneration. Our results reflect the diversity of synaptic pathology in neurodegenerative dementias.

Cerebrospinal Fluid Panel of Synaptic Proteins in Cerebral Amyloid Angiopathy and Alzheimer's Disease.

Alzheimer's disease (AD) and cerebral amyloid angiopathy (CAA) share pathogenic pathways related to amyloid-β deposition. Whereas AD is known to affect synaptic function, such an association for CAA remains yet unknown. We therefore aimed to investigate synaptic dysfunction in CAA. Multiple reaction monitoring mass spectrometry was used to quantify cerebrospinal fluid (CSF) concentrations of 15 synaptic proteins in CAA and AD patients, and age- and sex-matched cognitively unimpaired controls. We included 25 patients with CAA, 49 patients with AD, and 25 controls. Only neuronal pentraxin-2 levels were decreased in the CSF of CAA patients compared with controls (p = 0.04). CSF concentrations of 12 other synaptic proteins were all increased in AD compared with CAA or controls (all p≤0.01) and were unchanged between CAA and controls. Synaptic protein concentrations in the subgroup of CAA patients positive for AD biomarkers (CAA/ATN+; n = 6) were similar to AD patients, while levels in CAA/ATN- (n = 19) were comparable with those in controls. A regression model including all synaptic proteins differentiated CAA from AD at high accuracy levels (area under the curve 0.987). In contrast to AD, synaptic CSF biomarkers were found to be largely unchanged in CAA. Moreover, concomitant AD pathology in CAA is associated with abnormal synaptic protein levels. Impaired synaptic function in AD was confirmed in this independent cohort. Our findings support an apparent differential involvement of synaptic dysfunction in CAA and AD and may reflect distinct pathological mechanisms.

Development of a Signature Based on Eight Metastatic-Related Genes for Prognosis of GC Patients.

Gastric cancer (GC) has been a common tumor type with high mortality. Distal metastasis is one of the main causes of death in GC patients, which is also related to poor prognosis. The mRNA profiles and clinical information of GC patients were downloaded from The Cancer Genome Atlas and Gene Expression Omnibus databases. Univariate Cox and LASSO Cox analyses were used to screen the optimal metastasis-related genes (MRGs) to establish a prognostic Risk Score model for GC patients. The nomogram was used to visualize the Risk Score and predict the 1-, 3-, 5-year survival rate. The immune cell infiltration was analyzed by CIBERSORT and the ratio of immune-stromal component was calculated by the ESTIMATE algorithm. A total of 142 differentially expressed genes were identified between metastatic and non-metastatic GC samples. The optimal 8 genes, comprising GAMT (guanidinoacetate N-methyltransferase), ABCB5 (ATP-binding cassette subfamily B member 5), ITIH3 (inter-alpha-trypsin inhibitor heavy chain 3), GDF3 (growth differentiation factor 3), VSTM2L (V-set and transmembrane domain-containing 2 like), CIDEA (cell death inducing DFFA like effector a), NPTX1 (neuronal pentraxin-1), and UMOD (uromodulin), were further screened to establish a prognostic Risk Score, which proved to be an independent prognostic factor. Patients in high-risk group had a poor prognosis. There were significant differences in the proportion of 11 tumor-infiltrating immune cells between high-risk and low-risk subgroups. In addition, the StromalScore, ImmuneScore, and ESTIMATEScore in high-risk group were higher than those in low-risk group, indicating that the tumor microenvironment of the high-risk group was more complex. A Risk Score model based on eight metastasis-related genes could clearly distinguish the prognosis of GC patients. The poor prognosis of patients with high-Risk Score might be associated with the complex tumor microenvironments.

NPTX2 Promotes Epithelial–Mesenchymal Transition in Cutaneous Squamous Cell Carcinoma through METTL3-Mediated N6-Methyladenosine Methylation of SNAIL

Cutaneous squamous cell carcinoma (cSCC) is the second most common type of skin cancer. NPTX2, a member of the neuronal pentraxin family, is reported to play inconsistent roles in different cancers. The role and mechanism of NPTX2 in cSCC remain unclear. In this study, we found that NPTX2 was overexpressed in both skin lesions and cell lines of cSCC. Invitro studies showed that NPTX2 facilitated cell proliferation, migration, invasion, colony formation, and epithelial‒mesenchymal translation in A431 and SCL-1 cells. NPTX2 interacted with METTL3, increased METTL3 expression, and improved N6-methyladenosine modification in cSCC cell lines. Mechanistically, NPTX2 facilitated epithelial‒mesenchymal translation by promoting METTL3-mediated N6-methyladenosine of SNAIL. METTL3 knockdown and N6-methyladenosine inhibition reversed the impacts of NPTX2 overexpression on cSCC cells. Invivo studies verified the role of NPTX2 as an oncogene in cSCC. Therefore, NPTX2 may be a potential therapeutic target for cSCC.

Cerebrospinal Fluid Biomarkers of Synaptic Dysfunction are Altered in Parkinson's Disease and Related Disorders.

Synaptic dysfunction and degeneration are central contributors to the pathogenesis and progression of parkinsonian disorders. Therefore, identification and validation of biomarkers reflecting pathological synaptic alterations are greatly needed and could be used in prognostic assessment and to monitor treatment effects. To explore candidate biomarkers of synaptic dysfunction in Parkinson's disease (PD) and related disorders. Mass spectrometry was used to quantify 15 synaptic proteins in two clinical cerebrospinal fluid (CSF) cohorts, including PD (n1 =51, n2 =101), corticobasal degeneration (CBD) (n1 =11, n2 =3), progressive supranuclear palsy (PSP) (n1 =22, n2 =21), multiple system atrophy (MSA) (n1 =31, n2 =26), and healthy control (HC) (n1 =48, n2 =30) participants, as well as Alzheimer's disease (AD) (n2 =23) patients in the second cohort. Across both cohorts, lower levels of the neuronal pentraxins (NPTX; 1, 2, and receptor) were found in PD, MSA, and PSP, compared with HC. In MSA and PSP, lower neurogranin, AP2B1, and complexin-2 levels compared with HC were observed. In AD, levels of 14-3-3 zeta/delta, beta- and gamma-synuclein were higher compared with the parkinsonian disorders. Lower pentraxin levels in PD correlated with Mini-Mental State Exam scores and specific cognitive deficits (NPTX2; rho=0.25-0.32, P < 0.05) and reduced dopaminergic pre-synaptic integrity as measured by DaTSCAN (NPTX2; rho=0.29, P=0.023). Additionally, lower levels were associated with the progression of postural imbalance and gait difficulty symptoms (All NPTX; β-estimate=-0.025 to -0.038, P < 0.05) and cognitive decline (NPTX2; β-estimate=0.32, P=0.021). These novel findings show different alterations of synaptic proteins in parkinsonian disorders compared with AD and HC. The neuronal pentraxins may serve as prognostic CSF biomarkers for both cognitive and motor symptom progression in PD. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

The First Pituitary Proteome Landscape From Matched Anterior and Posterior Lobes for a Better Understanding of the Pituitary Gland

To date, very few mass spectrometry (MS)–based proteomics studies are available on the anterior and posterior lobes of the pituitary. In the past, MS-based investigations have focused exclusively on the whole pituitary gland or anterior pituitary lobe. In this study, for the first time, we performed a deep MS-based analysis of five anterior and five posterior matched lobes to build the first lobe-specific pituitary proteome map, which documented 4090 proteins with isoforms, mostly mapped into chromosomes 1, 2, and 11. About 1446 differentially expressed significant proteins were identified, which were studied for lobe specificity, biological pathway enrichment, protein–protein interaction, regions specific to comparison of human brain and other neuroendocrine glands from Human Protein Atlas to identify pituitary-enriched proteins. Hormones specific to each lobe were also identified and validated with parallel reaction monitoring–based target verification. The study identified and validated hormones, growth hormone and thyroid-stimulating hormone subunit beta, exclusively to the anterior lobe whereas oxytocin–neurophysin 1 and arginine vasopressin to the posterior lobe. The study also identified proteins POU1F1 (pituitary-specific positive transcription factor 1), POMC (pro-opiomelanocortin), PCOLCE2 (procollagen C-endopeptidase enhancer 2), and NPTX2 (neuronal pentraxin-2) as pituitary-enriched proteins and was validated for their lobe specificity using parallel reaction monitoring. In addition, three uPE1 proteins, namely THEM6 (mesenchymal stem cell protein DSCD75), FSD1L (coiled-coil domain–containing protein 10), and METTL26 (methyltransferase-like 26), were identified using the NeXtProt database, and depicted tumor markers S100 proteins having high expression in the posterior lobe. In summary, the study documents the first matched anterior and posterior pituitary proteome map acting as a reference control for a better understanding of functional and nonfunctional pituitary adenomas and extrapolating the aim of the Human Proteome Project towards the investigation of the proteome of life.

Synaptic dysfunction reflected in CSF: serial CSF sampling reveals trajectories of potential synaptic biomarkers in early AD stages

AbstractBackgroundSynaptic dysfunction plays an important role in Alzheimer’s disease (AD) and cognitive decline. Using serial CSF sampling we investigated longitudinal trajectories of synaptic proteins, including SYT1, SNAP25, neurogranin, synucleins, neuronal pentraxins (NPTX) and three 14‐3‐3 proteins, in AD.MethodsWe included 150 subjects with subjective cognitive decline (SCD; 62±7 years), mild cognitive impairment (MCI; 66±8 years) or AD dementia (64±7 years) from the Amsterdam dementia cohort, based on availability of CSF at two time points and clinical follow‐up of more than one year (median[interquartile range] 3.3[2.1‐5.1] years). Synaptic proteins were analyzed using two different mass spectrometry‐based assays. We used linear mixed models to assess whether baseline protein levels and slopes over time differed between groups (first analysis), and to assess associations of protein levels with cognitive function at baseline and decline over time, measured by repeated MMSE (second analysis). We first compared groups according to baseline diagnosis. Secondly, non‐demented subjects were compared based on CSF AD profile (i.e. abnormal Ab42 and tau levels; 60 AD‐ and 40 AD+ subjects). All protein levels were transformed to Z‐scores for comparison of effect sizes and were evaluated in separate models.ResultsAt baseline levels of SNAP25, neurogranin, beta‐synuclein and 14‐3‐3 proteins were higher in AD dementia than in SCD and MCI (figure 1), and in non‐demented AD+ versus AD‐ subjects. NPTX‐2 levels were lower in AD compared with SCD. Over time SYT1, NPTX‐1, NPTX‐2 and NPTX‐receptor decreased in AD dementia patients (st.B between ‐0.10 and ‐0.15; figure 2A), while 14‐3‐3 zeta/delta increased in MCI subjects (st.B[SE] 0.08[0.03]). Similar changes were seen in non‐demented AD+ subjects (Figure 2B). In SCD subjects lower baseline levels of NPTX‐2 were associated with lower baseline MMSE. In SCD and MCI subjects higher levels of SNAP25, Ng, synucleins and 14‐3‐3 proteins were associated with faster cognitive decline.ConclusionCSF levels of SYT1 and NPTX decreased over time in subjects with early symptomatic AD, while higher baseline levels of other synaptic proteins were associated with future disease progression. This dissociation may reflect complex synaptic changes in early disease stages and may have added value in a prognostic model for AD.

The fluid biomarker landscape in genetic FTD

AbstractBackgroundThere is an increasing need for the use of fluid biomarkers in clinical management and future therapeutic trials of patients with genetic FTD.MethodSeveral fluid biomarkers have been investigated in the largest longitudinal cohort of patients with genetic FTD (GENFI; n &gt; 1000) associated with mutations in the progranulin (GRN), MAPtau and C9orf72 gene. Concentration changes in neurofilament light and neurofilament high protein (NfL and pNfH), neuronal pentraxin (NPTX2), glial fibrillary acidic protein (GFAP), dipeptides, complement factors and miRNAs have been correlated with disease onset and progression, disease severity and grey matter volume loss in pre‐ and symptomatic carriers. Sequences of biomarker abnormalities were analyzed using discriminative event‐based modelling (DEBM).ResultA number of promising fluid biomarkers have been identified in all or in specific genetic subtypes of FTD, with a specific sequence of biomarker changes over time from pre‐ to symptomatic stage. The next step will bet he development of a multi‐modal prediction tool at individual level, which may improve patient stratification and track the efficacy of therapeutic interventions.ConclusionMajor scientific achievements have been made in fluid biomarker studies of the largest cohort of genetic FTD (GENFI).

A Combination of Neurofilament Light, Glial Fibrillary Acidic Protein, and Neuronal Pentraxin-2 Discriminates Between Frontotemporal Dementia and Other Dementias.

The differential diagnosis of frontotemporal dementia (FTD) is still a challenging task due to its symptomatic overlap with other neurological diseases and the lack of biofluid-based biomarkers. To investigate the diagnostic potential of a combination of novel biomarkers in cerebrospinal fluid (CSF) and blood. We included 135 patients from the Center for Memory Disturbances, University of Perugia, with the diagnoses FTD (n = 37), mild cognitive impairment due to Alzheimer's disease (MCI-AD, n = 47), Lewy body dementia (PDD/DLB, n = 22), and cognitively unimpaired patients as controls (OND, n = 29). Biomarker levels of neuronal pentraxin-2 (NPTX2), neuronal pentraxin receptor, neurofilament light (NfL) and glial fibrillary acidic protein (GFAP) were measured in CSF, as well as NfL and GFAP in serum. We assessed biomarker differences by analysis of covariance and generalized linear models (GLM). We performed receiver operating characteristics analyses and Spearman correlation to determine biomarker associations. CSF NPTX2 and serum GFAP levels varied most between diagnostic groups. The combination of CSF NPTX2, serum NfL and serum GFAP differentiated FTD from the other groups with good accuracy (FTD versus MCI-AD: area under the curve (AUC) [95% CI] = 0.89 [0.81-0.96]; FTD versus PDD/DLB: AUC = 0.82 [0.71-0.93]; FTD versus OND: AUC = 0.80 [0.70-0.91]). CSF NPTX2 and serum GFAP correlated positively only in PDD/DLB (ρ= 0.56, p < 0.05). NPTX2 and serum NfL did not correlate in any of the diagnostic groups. Serum GFAP and serum NfL correlated positively in all groups (ρ= 0.47-0.74, p < 0.05). We show the combined potential of CSF NPTX2, serum NfL, and serum GFAP to differentiate FTD from other neurodegenerative disorders.

Cerebrospinal fluid biomarker panel of synaptic dysfunction in Alzheimer's disease and other neurodegenerative disorders.

Synaptic degeneration is a key part of the pathophysiology of neurodegenerative diseases, and biomarkers reflecting the pathological alterations are greatly needed. Seventeen synaptic proteins were quantified in a pathology-confirmed cerebrospinal fluid cohort of patients with Alzheimer's disease (AD; n=63), frontotemporal lobar degeneration (FTLD; n=53), and Lewy body spectrum of disorders (LBD; n=21), as well as healthy controls (HC; n=48). Comparisons revealed four distinct patterns: markers decreased across all neurodegenerative conditions compared to HC (the neuronal pentraxins), markers increased across all neurodegenerative conditions (14-3-3 zeta/delta), markers selectively increased in AD compared to other neurodegenerative conditions (neurogranin and beta-synuclein), and markers selectively decreased in LBD and FTLD compared to HC and AD (AP2B1 and syntaxin-1B). Several of the synaptic proteins may serve as biomarkers for synaptic dysfunction in AD, LBD, and FTLD. Additionally, differential patterns of synaptic protein alterations seem to be present across neurodegenerative diseases. A panel of synaptic proteins were quantified in the cerebrospinal fluid using mass spectrometry. We compared Alzheimer's disease, frontotemporal degeneration, and Lewy body spectrum of disorders. Pathology was confirmed by autopsy or familial mutations. We discovered synaptic biomarkers for synaptic degeneration and cognitive decline. We found differential patterns of synaptic proteins across neurodegenerative diseases.

CSF peptides from VGF and other markers enhance prediction of MCI to AD progression using the ATN framework

The amyloid beta, tau, neurodegenerative markers framework has been proposed to serve as a system to classify and combine biomarkers for Alzheimer's Disease (AD). Although cerebrospinal (CSF) fluid AT (amyloid beta and tau)-based biomarkers have a well-established track record to distinguish AD from control subjects and to predict conversion from mild cognitive impairment (MCI) to AD, there is not an established non-tau based neurodegenerative (“N”) marker from CSF. Here, we examine the ability of several candidate peptides in the CSF to serve as “N” markers to both classify disease state and predict MCI to AD conversion. We observed that although many putative N markers involved in synaptic processing and neuroinflammation were able to, when examined in isolation, distinguish MCI converters from non-converters, a derivative from VGF, when combined with AT markers, most strongly enhanced prediction of MCI to AD conversion. Low CSF VGF levels were also predictive of MCI to dementia conversion in the setting of normal AT markers, suggesting that it may serve as a very early predictor of dementia conversion. Other markers derived from neuronal pentraxin 2, GAP-43 and a 14-3-3 protein were also able to enhance MCI to AD prediction when used as a marker of neurodegeneration, but VGF had the highest predictive capacity. Thus, we propose that low levels of VGF in CSF may serve as “N” in the amyloid beta, tau, neurodegenerative markers framework to enhance the prediction of MCI to AD conversion.

Evaluation of Synaptic and Axonal Dysfunction Biomarkers in Alzheimer's Disease and Mild Cognitive Impairment Based on CSF and Bioinformatic Analysis.

Synaptic loss and dysfunction are one of the earliest signs of neurodegeneration associated with cognitive decline in Alzheimer’s disease (AD) and other neurodegenerative diseases. This study aimed to assess the relationships between biological processes of the synaptic pathology underlying AD, molecular functions, and dynamics of the change concentrations of selected proteins reflecting synaptic and axonal pathology in dementia stages. Neurogranin (Ng), neuronal pentraxin receptor (NPTXR), and Visinin-like protein 1 (VILIP1) concentrations were measured in the cerebrospinal fluid (CSF) of MCI, AD, and non-demented controls (CTRL) using quantitative immunological methods. Gene ontology (GO) enrichment analysis was used for the functional analysis of tested proteins. The CSF Aβ42/Ng ratio was significantly different between all the compared groups. The CSF NPTXR/Ng ratio was significantly different between MCI compared to CTRL and AD compared to CTRL. The GO enrichment analysis revealed that two terms (the Biological Process (BP) and Cellular Component (CC) levels) are significantly enriched for NPTXR and Ng but not for VILIP1. Both Ng and NPTXR concentrations in CSF are promising synaptic dysfunction biomarkers for the early diagnosis of the disease. Moreover, both proteins are biochemically associated with classical biomarkers and VILIP-1. Mapping shared molecular and biological functions for the tested proteins by GO enrichment analysis may be beneficial in screening and setting new research targets.

Differential impairment of cerebrospinal fluid synaptic biomarkers in the genetic forms of frontotemporal dementia

BackgroundApproximately a third of frontotemporal dementia (FTD) is genetic with mutations in three genes accounting for most of the inheritance: C9orf72, GRN, and MAPT. Impaired synaptic health is a common mechanism in all three genetic variants, so developing fluid biomarkers of this process could be useful as a readout of cellular dysfunction within therapeutic trials.MethodsA total of 193 cerebrospinal fluid (CSF) samples from the GENetic FTD Initiative including 77 presymptomatic (31 C9orf72, 23 GRN, 23 MAPT) and 55 symptomatic (26 C9orf72, 17 GRN, 12 MAPT) mutation carriers as well as 61 mutation-negative controls were measured using a microflow LC PRM-MS set-up targeting 15 synaptic proteins: AP-2 complex subunit beta, complexin-2, beta-synuclein, gamma-synuclein, 14–3-3 proteins (eta, epsilon, zeta/delta), neurogranin, Rab GDP dissociation inhibitor alpha (Rab GDI alpha), syntaxin-1B, syntaxin-7, phosphatidylethanolamine-binding protein 1 (PEBP-1), neuronal pentraxin receptor (NPTXR), neuronal pentraxin 1 (NPTX1), and neuronal pentraxin 2 (NPTX2). Mutation carrier groups were compared to each other and to controls using a bootstrapped linear regression model, adjusting for age and sex.ResultsCSF levels of eight proteins were increased only in symptomatic MAPT mutation carriers (compared with controls) and not in symptomatic C9orf72 or GRN mutation carriers: beta-synuclein, gamma-synuclein, 14–3-3-eta, neurogranin, Rab GDI alpha, syntaxin-1B, syntaxin-7, and PEBP-1, with three other proteins increased in MAPT mutation carriers compared with the other genetic groups (AP-2 complex subunit beta, complexin-2, and 14–3-3 zeta/delta). In contrast, CSF NPTX1 and NPTX2 levels were affected in all three genetic groups (decreased compared with controls), with NPTXR concentrations being affected in C9orf72 and GRN mutation carriers only (decreased compared with controls). No changes were seen in the CSF levels of these proteins in presymptomatic mutation carriers. Concentrations of the neuronal pentraxins were correlated with brain volumes in the presymptomatic period for the C9orf72 and GRN groups, suggesting that they become abnormal in proximity to symptom onset.ConclusionsDifferential synaptic impairment is seen in the genetic forms of FTD, with abnormalities in multiple measures in those with MAPT mutations, but only changes in neuronal pentraxins within the GRN and C9orf72 mutation groups. Such markers may be useful in future trials as measures of synaptic dysfunction, but further work is needed to understand how these markers change throughout the course of the disease.

Comprehensive Analysis of Chromatin Accessibility and Transcriptional Landscape Identified BRCA1 Repression as a Potential Pathological Factor for Keloid

Keloid is a poorly understood fibrotic skin disease that commonly occurs during wound-healing. As a polymer composed of nucleic acid and proteins, the structure of chromatin could be dynamically regulated in the nucleus. In this study, we explored the dynamics of chromatin accessibility and the transcriptome in dermal fibroblasts (DFs) in keloid formation. Compared to normal samples, chromatin accessibility and transcriptome were extensively altered in keloid DFs. In addition, changes in chromatin accessibility were closely associated with changes in gene expression in DFs. Breast cancer type 1 (BRCA1) was significantly downregulated in keloid DFs, and its knockdown promoted the proliferation and attenuated the migration ability of normal DF cells. Mechanistically, BRCA1 suppression significantly reduced the expression of neuronal pentraxin 2 (NPTX2), a cell viability-related gene. BRCA1 binding affinity at the NPTX2 enhancer and the chromatin accessibility in the same region were significantly lower in keloid DFs than in normal DFs, which might contribute to NPTX2 inhibition. In conclusion, this study identified BRCA1 inhibition in DFs as a novel pathological factor in keloids and preliminarily explored its potential mechanisms, which will help us understand the formation of keloids.

Competitive inhibition of the classical complement pathway using exogenous single-chain C1q recognition proteins

Complement component C1q is a protein complex of the innate immune system with well-characterized binding partners that constitutes part of the classical complement pathway. In addition, C1q was recently described in the central nervous system as having a role in synapse elimination both in the healthy brain and in neurodegenerative diseases. However, the molecular mechanism of C1q-associated synapse phagocytosis is still unclear. Here, we designed monomer and multimer protein constructs, which comprised the globular interaction recognition parts of mouse C1q (globular part of C1q [gC1q]) as single-chain molecules (sc-gC1q proteins) lacking the collagen-like effector region. These molecules, which can competitively inhibit the function of C1q, were expressed in an Escherichia coli expression system, and their structure and capabilities to bind known complement pathway activators were validated by mass spectrometry, analytical size-exclusion chromatography, analytical ultracentrifugation, CD spectroscopy, and ELISA. We further characterized the interactions between these molecules and immunoglobulins and neuronal pentraxins using surface plasmon resonance spectroscopy. We demonstrated that sc-gC1qs potently inhibited the function of C1q. Furthermore, these sc-gC1qs competed with C1q in binding to the embryonal neuronal cell membrane. We conclude that the application of sc-gC1qs can reveal neuronal localization and functions of C1q in assays in vivo and might serve as a basis for engineering inhibitors for therapeutic purposes.

High Sensitivity Simoa Immunoassays to Evaluate Levels of Postsynaptic density protein 95 and Neuronal Pentraxin II as Predictors of Cognitive Function Loss in Alzheimer’s Diseases (P3-3.004)

High Sensitivity Simoa Immunoassays to Evaluate Levels of Postsynaptic density protein 95 and Neuronal Pentraxin II as Predictors of Cognitive Function Loss in Alzheimer’s Diseases (P3-3.004)

Neuronal pentraxin 2 is required for facilitating excitatory synaptic inputs onto spinal neurons involved in pruriceptive transmission in a model of chronic itch

An excitatory neuron subset in the spinal dorsal horn (SDH) that expresses gastrin-releasing peptide receptors (GRPR) is critical for pruriceptive transmission. Here, we show that glutamatergic excitatory inputs onto GRPR+ neurons are facilitated in mouse models of chronic itch. In these models, neuronal pentraxin 2 (NPTX2), an activity-dependent immediate early gene product, is upregulated in the dorsal root ganglion (DRG) neurons. Electron microscopy reveals that NPTX2 is present at presynaptic terminals connected onto postsynaptic GRPR+ neurons. NPTX2-knockout prevents the facilitation of synaptic inputs to GRPR+ neurons, and repetitive scratching behavior. DRG-specific NPTX2 expression rescues the impaired behavioral phenotype in NPTX2-knockout mice. Moreover, ectopic expression of a dominant-negative form of NPTX2 in DRG neurons reduces chronic itch-like behavior in mice. Our findings indicate that the upregulation of NPTX2 expression in DRG neurons contributes to the facilitation of glutamatergic inputs onto GRPR+ neurons under chronic itch-like conditions, providing a potential therapeutic target.

Neuronal pentraxin-2 (NPTX2) serum levels during an acute psychotic episode in patients with schizophrenia

Neuronal pentraxin-2 (NPTX2, an immediate-early gene), which regulates synapse activity and neuroplasticity, plays an essential role in the neurodevelopmental process. NPTX2 possibly enhances the accumulation of amino-3-hydroxy-5-methyl-4-isoxazolepropionic receptors (AMPAR) on the postsynaptic membranes and stimulates excitatory synaptogenesis. We aimed to evaluate the plasma concentrations of NPTX2 of patients with schizophrenia in acute psychotic episodes compared with matched community-based controls. Ninety-three (93) patients diagnosed with schizophrenia according to DSM-5 and 83 healthy controls were included. The patients, all of which were in acute psychotic episodes, were recruited from the inpatient clinic. The patients were assessed by the Positive and Negative Syndrome Scale (PANSS) and Clinical Global Impression- Severity (CGIS) scale, whereas the healthy subjects were evaluated with Structured Clinical Interview for DSM-5 (SCID-5) to exclude any major psychiatric diagnoses. NPTX2 serum concentrations were significantly higher in the schizophrenia group (p < 0.001). NPTX2 levels negatively correlated with age (p = 0.004) and PANSS-positive symptom scores (p < 0.001). The most determinant factors in predicting the change in NPTX2 levels were PANSS-positive symptom and general psychopathology scores. We conclude that NPTX2 could be involved in schizophrenia pathophysiology and valuable as a synapse-derived and glutamate-related biomarker. Further studies in larger samples assessing NPTX2 levels in remitted schizophrenia patients and combining neuroimaging techniques and cognitive evaluations with blood samples are needed.