Lotun, A;Li, D;Xu, H;Su, Q;Tuncer, S;Sanmiguel, J;Mooney, M;Baer, CE;Ulbrich, R;Eyles, SJ;Strittmatter, L;Hayward, LJ;Gessler, DJ;Gao, G;
PMID: 37149081 | DOI: 10.1016/j.pneurobio.2023.102460
Myelinating oligodendrocytes are essential for neuronal communication and homeostasis of the central nervous system (CNS). One of the most abundant molecules in the mammalian CNS is N-acetylaspartate (NAA), which is catabolized into L-aspartate and acetate by the enzyme aspartoacylase (ASPA) in oligodendrocytes. The resulting acetate moiety is thought to contribute to myelin lipid synthesis. In addition, affected NAA metabolism has been implicated in several neurological disorders, including leukodystrophies and demyelinating diseases such as multiple sclerosis. Genetic disruption of ASPA function causes Canavan disease, which is hallmarked by increased NAA levels, myelin and neuronal loss, large vacuole formation in the CNS, and early death in childhood. Although NAA's direct role in the CNS is inconclusive, in peripheral adipose tissue, NAA-derived acetate has been found to modify histones, a mechanism known to be involved in epigenetic regulation of cell differentiation. We hypothesize that a lack of cellular differentiation in the brain contributes to the disruption of myelination and neurodegeneration in diseases with altered NAA metabolism, such as Canavan disease. Our study demonstrates that loss of functional Aspa in mice disrupts myelination and shifts the transcriptional expression of neuronal and oligodendrocyte markers towards less differentiated stages in a spatiotemporal manner. Upon re-expression of ASPA, these oligodendrocyte and neuronal lineage markers are either improved or normalized, suggesting that NAA breakdown by Aspa plays an essential role in the maturation of neurons and oligodendrocytes. Also, this effect of ASPA re-expression is blunted in old mice, potentially due to limited ability of neuronal, rather than oligodendrocyte, recovery.
Delorme JE, Kodoth V, Aton SJ.
PMID: 29635031 | DOI: 10.1016/j.nlm.2018.04.006
Sleep loss affects many aspects of cognition, and memory consolidation processes occurring in the hippocampus seem particularly vulnerable to sleep loss. The immediate-early gene Arc plays an essential role in both synaptic plasticity and memory formation, and its expression is altered by sleep. Here, using a variety of techniques, we have characterized the effects of brief (3-h) periods of sleep vs. sleep deprivation (SD) on the expression of Arc mRNA and Arc protein in the mouse hippocampus and cortex. By comparing the relative abundance of mature Arc mRNA with unspliced pre-mRNA, we see evidence that during SD, increases in Arc across the cortex, but not hippocampus, reflect de novo transcription. Arc increases in the hippocampus during SD are not accompanied by changes in pre-mRNA levels, suggesting that increases in mRNA stability, not transcription, drives this change. Using in situ hybridization (together with behavioral observation to quantify sleep amounts), we find that in the dorsal hippocampus, SD minimally affects Arc mRNA expression, and decreases the number of dentate gyrus (DG) granule cells expressing Arc. This is in contrast to neighboring cortical areas, which show large increases in neuronal Arc expression after SD. Using immunohistochemistry, we find that Arc protein expression is also differentially affected in the cortex and DG with SD - while larger numbers of cortical neurons are Arc+, fewer DG granule cells are Arc+, relative to the same regions in sleeping mice. These data suggest that with regard to expression of plasticity-regulating genes, sleep (and SD) can have differential effects in hippocampal and cortical areas. This may provide a clue regarding the susceptibility of performance on hippocampus-dependent tasks to deficits following even brief periods of sleep loss.
Hilscher, MM;Langseth, CM;Kukanja, P;Yokota, C;Nilsson, M;Castelo-Branco, G;
PMID: 35610641 | DOI: 10.1186/s12915-022-01325-z
Oligodendrocytes are glial cells that support and insulate axons in the central nervous system through the production of myelin. Oligodendrocytes arise throughout embryonic and early postnatal development from oligodendrocyte precursor cells (OPCs), and recent work demonstrated that they are a transcriptional heterogeneous cell population, but the regional and functional implications of this heterogeneity are less clear. Here, we apply in situ sequencing (ISS) to simultaneously probe the expression of 124 marker genes of distinct oligodendrocyte populations, providing comprehensive maps of the corpus callosum, cingulate, motor, and somatosensory cortex in the brain, as well as gray matter (GM) and white matter (WM) regions in the spinal cord, at postnatal (P10), juvenile (P20), and young adult (P60) stages. We systematically compare the abundances of these populations and investigate the neighboring preference of distinct oligodendrocyte populations.We observed that oligodendrocyte lineage progression is more advanced in the juvenile spinal cord compared to the brain, corroborating with previous studies. We found myelination still ongoing in the adult corpus callosum while it was more advanced in the cortex. Interestingly, we also observed a lateral-to-medial gradient of oligodendrocyte lineage progression in the juvenile cortex, which could be linked to arealization, as well as a deep-to-superficial gradient with mature oligodendrocytes preferentially accumulating in the deeper layers of the cortex. The ISS experiments also exposed differences in abundances and population dynamics over time between GM and WM regions in the brain and spinal cord, indicating regional differences within GM and WM, and we found that neighboring preferences of some oligodendroglia populations are altered from the juvenile to the adult CNS.Overall, our ISS experiments reveal spatial heterogeneity of oligodendrocyte lineage progression in the brain and spinal cord and uncover differences in the timing of oligodendrocyte differentiation and myelination, which could be relevant to further investigate functional heterogeneity of oligodendroglia, especially in the context of injury or disease.
An increase in VGF expression through a rapid, transcription-independent, autofeedback mechanism improves cognitive function
Lin, WJ;Zhao, Y;Li, Z;Zheng, S;Zou, JL;Warren, NA;Bali, P;Wu, J;Xing, M;Jiang, C;Tang, Y;Salton, SR;Ye, X;
PMID: 34238925 | DOI: 10.1038/s41398-021-01489-2
The release of neuropeptides from dense core vesicles (DCVs) modulates neuronal activity and plays a critical role in cognitive function and emotion. The granin family is considered a master regulator of DCV biogenesis and the release of DCV cargo molecules. The expression of the VGF protein (nonacronymic), a secreted neuropeptide precursor that also belongs to the extended granin family, has been previously shown to be induced in the brain by hippocampus-dependent learning, and its downregulation is mechanistically linked to neurodegenerative diseases such as Alzheimer's disease and other mood disorders. Currently, whether changes in translational efficiency of Vgf and other granin mRNAs may be associated and regulated with learning associated neural activity remains largely unknown. Here, we show that either contextual fear memory training or the administration of TLQP-62, a peptide derived from the C-terminal region of the VGF precursor, acutely increases the translation of VGF and other granin proteins, such as CgB and Scg2, via an mTOR-dependent signaling pathway in the absence of measurable increases in mRNA expression. Luciferase-based reporter assays confirmed that the 3'-untranslated region (3'UTR) of the Vgf mRNA represses VGF translation. Consistently, the truncation of the endogenous Vgf mRNA 3'UTR results in substantial increases in VGF protein expression both in cultured primary neurons and in brain tissues from knock in mice expressing a 3'UTR-truncation mutant encoded by the modified Vgf gene. Importantly, Vgf 3'UTR-truncated mice exhibit enhanced memory performance and reduced anxiety- and depression-like behaviors. Our results therefore reveal a rapid, transcription-independent induction of VGF and other granin proteins after learning that are triggered by the VGF-derived peptide TLQP-62. Our findings suggest that the rapid, positive feedforward increase in the synthesis of granin family proteins might be a general mechanism to replenish DCV cargo molecules that have been released in response to neuronal activation and is crucial for memory function and mood stability.
Nikitin, P;Musina, G;Pekov, S;Kuzin, A;Popov, I;Belyaev, A;Kobyakov, G;Usachev, D;Nikolaev, V;Mikhailov, V;
| DOI: 10.3390/cancers15010145
Diffuse gliomas continue to be an important problem in neuro-oncology. To solve it, studies have considered the issues of molecular pathogenesis from the intratumoral heterogeneity point. Here, we carried out a comparative dynamic analysis of the different cell populations’ content in diffuse gliomas of different molecular profiles and grades, considering the cell populations’ functional properties and the relationship with patient survival, using flow cytometry, immunofluorescence, multiparametric fluorescent in situ hybridization, polymerase chain reaction, and cultural methods. It was shown that an increase in the IDH-mutant astrocytomas and oligodendrogliomas malignancy is accompanied by an increase in stem cells’ proportion and mesenchymal cell populations’ appearance arising from oligodendrocyte-progenitor-like cells with cell plasticity and cells’ hypoxia response programs’ activation. In glioblastomas, malignancy increase is accompanied by an increase in both stem and definitive cells with mesenchymal differentiation, while proneuronal glioma stem cells are the most likely the source of mesenchymal glioma stem cells, which, in hypoxic conditions, further give rise to mesenchymal-like cells. Clinical confirmation was a mesenchymal-like cell and mesenchymal glioma stem cell number, and the hypoxic and plastic molecular programs’ activation degree had a significant effect on relapse-free and overall survival. In general, we built a multi-vector model of diffuse gliomas’ pathogenetic tracing up to the practical plane.
Variation in phenotypes from a Bmp-Gata3 genetic pathway is modulated by Shh signaling
Swartz, ME;Lovely, CB;Eberhart, JK;
PMID: 34033651 | DOI: 10.1371/journal.pgen.1009579
We sought to understand how perturbation of signaling pathways and their targets generates variable phenotypes. In humans, GATA3 associates with highly variable defects, such as HDR syndrome, microsomia and choanal atresia. We previously characterized a zebrafish point mutation in gata3 with highly variable craniofacial defects to the posterior palate. This variability could be due to residual Gata3 function, however, we observe the same phenotypic variability in gata3 null mutants. Using hsp:GATA3-GFP transgenics, we demonstrate that Gata3 function is required between 24 and 30 hpf. At this time maxillary neural crest cells fated to generate the palate express gata3. Transplantation experiments show that neural crest cells require Gata3 function for palatal development. Via a candidate approach, we determined if Bmp signaling was upstream of gata3 and if this pathway explained the mutant's phenotypic variation. Using BRE:d2EGFP transgenics, we demonstrate that maxillary neural crest cells are Bmp responsive by 24 hpf. We find that gata3 expression in maxillary neural crest requires Bmp signaling and that blocking Bmp signaling, in hsp:DN-Bmpr1a-GFP embryos, can phenocopy gata3 mutants. Palatal defects are rescued in hsp:DN-Bmpr1a-GFP;hsp:GATA3-GFP double transgenic embryos, collectively demonstrating that gata3 is downstream of Bmp signaling. However, Bmp attenuation does not alter phenotypic variability in gata3 loss-of-function embryos, implicating a different pathway. Due to phenotypes observed in hypomorphic shha mutants, the Sonic Hedgehog (Shh) pathway was a promising candidate for this pathway. Small molecule activators and inhibitors of the Shh pathway lessen and exacerbate, respectively, the phenotypic severity of gata3 mutants. Importantly, inhibition of Shh can cause gata3 haploinsufficiency, as observed in humans. We find that gata3 mutants in a less expressive genetic background have a compensatory upregulation of Shh signaling. These results demonstrate that the level of Shh signaling can modulate the phenotypes observed in gata3 mutants.
Voronova A, Yuzwa SA, Wang BS, Zahr S, Syal C, Wang J, Kaplan DR, Miller FD.
PMID: 28472653 | DOI: 10.1016/j.neuron.2017.04.018
During development, newborn interneurons migrate throughout the embryonic brain. Here, we provide evidence that these interneurons act in a paracrine fashion to regulate developmental oligodendrocyte formation. Specifically, we show that medial ganglionic eminence (MGE) interneurons secrete factors that promote genesis of oligodendrocytes from glially biased cortical precursors in culture. Moreover, when MGE interneurons are genetically ablated in vivo prior to their migration, this causes a deficit in cortical oligodendrogenesis. Modeling of the interneuron-precursor paracrine interaction using transcriptome data identifies the cytokine fractalkine as responsible for the pro-oligodendrocyte effect in culture. This paracrine interaction is important in vivo, since knockdown of the fractalkine receptor CX3CR1 in embryonic cortical precursors, or constitutive knockout of CX3CR1, causes decreased numbers of oligodendrocyte progenitor cells (OPCs) and oligodendrocytes in the postnatal cortex. Thus, in addition to their role in regulating neuronal excitability, interneurons act in a paracrine fashion to promote the developmental genesis of oligodendrocytes.
Kadur Lakshminarasimha Murthy, P;Sontake, V;Tata, A;Kobayashi, Y;Macadlo, L;Okuda, K;Conchola, AS;Nakano, S;Gregory, S;Miller, LA;Spence, JR;Engelhardt, JF;Boucher, RC;Rock, JR;Randell, SH;Tata, PR;
PMID: 35355018 | DOI: 10.1038/s41586-022-04541-3
Mapping the spatial distribution and molecular identity of constituent cells is essential for understanding tissue dynamics in health and disease. We lack a comprehensive map of human distal airways, including the terminal and respiratory bronchioles (TRBs), which are implicated in respiratory diseases1-4. Here, using spatial transcriptomics and single-cell profiling of microdissected distal airways, we identify molecularly distinct TRB cell types that have not-to our knowledge-been previously characterized. These include airway-associated LGR5+ fibroblasts and TRB-specific alveolar type-0 (AT0) cells and TRB secretory cells (TRB-SCs). Connectome maps and organoid-based co-cultures reveal that LGR5+ fibroblasts form a signalling hub in the airway niche. AT0 cells and TRB-SCs are conserved in primates and emerge dynamically during human lung development. Using a non-human primate model of lung injury, together with human organoids and tissue specimens, we show that alveolar type-2 cells in regenerating lungs transiently acquire an AT0 state from which they can differentiate into either alveolar type-1 cells or TRB-SCs. This differentiation programme is distinct from that identified in the mouse lung5-7. Our study also reveals mechanisms that drive the differentiation of the bipotent AT0 cell state into normal or pathological states. In sum, our findings revise human lung cell maps and lineage trajectories, and implicate an epithelial transitional state in primate lung regeneration and disease.
Dai J, Yang L, Xu T, Si L, Cui C, Sheng X, Chi Z, Mao L, Lian B, Tang B, Bai X, Zhou L, Li S, Wang X, Yan X, Kong Y, Guo J
PMID: 32226509 | DOI: 10.7150/jca.43010
Purpose: Polymorphisms of genes in the platelet-derived growth factor (PDGF) signaling pathway have been found to predict cutaneous melanoma (CM) survival, but their clinical effects in acral melanoma (AM) patients have not been explored. The aim of this study was to characterize the functional effect of the tag single-nucleotide polymorphism (SNP) rs2228230:C>T and assess its association with clinical outcomes in AM patients. Methods: The effect of rs2228230:C>T on mRNA structures and codon usage values were evaluated using in silico analyses. PDGF receptor alpha (PDGFRA) expression vectors with the rs2228230:C or rs2228230:T allele were constructed to evaluate the expression and signaling activity of PDGFRA. The expression of PDGFRA in AM samples was measured using in situ RNAscope hybridization and immunohistochemical staining. The association of the rs2228230 genotype with survival was analyzed in two independent AM cohorts. Results: In silico analyses indicated that the rs2228230:T allele increases the minimum free energy and reduces synonymous codon usage. The rs2228230:T allele decreased the expression of PDGFRA by reducing the stability of its mRNA and protein as well as the signaling activity of the MAPK and PI3K/AKT pathways. PDGFRA mRNA and protein expression was significantly reduced in AM tissues with the rs2228230:T allele. The progression-free survival and overall survival of AM patients with the rs2228230:T allele were significantly longer than those of patients with the CC genotype. Conclusion: Our study indicated that rs2228230:T can reduce the expression of PDGFRA and downstream signaling activity and is associated with better survival in AM patients.
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology
Velazquez-Sanchez, C;Muresan, L;Marti-Prats, L;Belin, D;
PMID: 36635597 | DOI: 10.1038/s41386-022-01522-y
Some compulsive disorders have been considered to stem from the loss of control over coping strategies, such as displacement. However, the cellular mechanisms involved in the acquisition of coping behaviours and their subsequent compulsive manifestation in vulnerable individuals have not been elucidated. Considering the role of the locus coeruleus (LC) noradrenaline-dependent system in stress and related excessive behaviours, we hypothesised that neuroplastic changes in the LC may be associated with the acquisition of an adjunctive polydipsic water drinking, a prototypical displacement behaviour, and the ensuing development of compulsion in vulnerable individuals. Thus, male Sprague Dawley rats were characterised for their tendency, or not, to develop compulsive polydipsic drinking in a schedule-induced polydipsia (SIP) procedure before their fresh brains were harvested. A new quantification tool for RNAscope assays revealed that the development of compulsive adjunctive behaviour was associated with a low mRNA copy number of the plasticity marker Arc in the LC which appeared to be driven by specific adaptations in an ensemble of tyrosine hydroxylase (TH)+, zif268- neurons. This ensemble was specifically engaged by the expression of compulsive adjunctive behaviour, not by stress, because its functional recruitment was not observed in individuals that no longer had access to the water bottle before sacrifice, while it consistently correlated with the levels of polydipsic water drinking only when it had become compulsive. Together these findings suggest that downregulation of Arc mRNA levels in a population of a TH+/zif268- LC neurons represents a signature of the tendency to develop compulsive coping behaviours.
Pentraxin 3 is a stromally-derived biomarker for detection of pancreatic ductal adenocarcinoma
Goulart, MR;Watt, J;Siddiqui, I;Lawlor, RT;Imrali, A;Hughes, C;Saad, A;ChinAleong, J;Hurt, C;Cox, C;Salvia, R;Mantovani, A;Crnogorac-Jurcevic, T;Mukherjee, S;Scarpa, A;Allavena, P;Kocher, HM;
PMID: 34188166 | DOI: 10.1038/s41698-021-00192-1
Pancreatic ductal adenocarcinoma (PDAC), characterized by dense desmoplastic stroma laid down by pancreatic stellate cells (PSC), has no reliable diagnostic biomarkers for timely detection. A multi-center cohort of PDAC patients and controls (chronic pancreatitis, intra-ductal papillary neoplasms, gallstones and otherwise healthy) donated serum in an ethically approved manner. Serum PTX3 above 4.34 ng/mL has a higher sensitivity (86%, 95% confidence interval (CI): 65-97%) and specificity (86%, 95% CI: 79-91%), positive predictive value (97%) and likelihood ratio (6.05), and is superior when compared to serum CA19-9 and CEA for detection of PDAC. In vitro and ex vivo analyses of PTX3, in human PDAC samples, PSCs, cell lines and transgenic mouse model for PDAC, suggest that PTX3 originates from stromal cells, mainly PSC. In activated PSC, PTX3 secretion could be downregulated by rendering PSC quiescent using all-trans-retinoic acid (ATRA). PTX3 organizes hyaluronan in conjunction with tumor necrosis factor-stimulated gene 6 (TSG-6) and facilitates stellate and cancer cell invasion. In SCALOP clinical trial (ISRCTN96169987) testing chemo-radiotherapy without stromal targeting, PTX3 had no prognostic or predictive role. However, in STARPAC clinical trial (NCT03307148), stromal modulation by ATRA even at first dose is accompanied with serum PTX3 response in patients who later go on to demonstrate disease control but not those in whom the disease progresses. PTX3 is a putative stromally-derived biomarker for PDAC which warrants further testing in prospective, larger, multi-center cohorts and within clinical trials targeting stroma.
De Schepper, S;Ge, JZ;Crowley, G;Ferreira, LSS;Garceau, D;Toomey, CE;Sokolova, D;Rueda-Carrasco, J;Shin, SH;Kim, JS;Childs, T;Lashley, T;Burden, JJ;Sasner, M;Sala Frigerio, C;Jung, S;Hong, S;
PMID: 36747024 | DOI: 10.1038/s41593-023-01257-z
Alzheimer's disease (AD) is characterized by synaptic loss, which can result from dysfunctional microglial phagocytosis and complement activation. However, what signals drive aberrant microglia-mediated engulfment of synapses in AD is unclear. Here we report that secreted phosphoprotein 1 (SPP1/osteopontin) is upregulated predominantly by perivascular macrophages and, to a lesser extent, by perivascular fibroblasts. Perivascular SPP1 is required for microglia to engulf synapses and upregulate phagocytic markers including C1qa, Grn and Ctsb in presence of amyloid-β oligomers. Absence of Spp1 expression in AD mouse models results in prevention of synaptic loss. Furthermore, single-cell RNA sequencing and putative cell-cell interaction analyses reveal that perivascular SPP1 induces microglial phagocytic states in the hippocampus of a mouse model of AD. Altogether, we suggest a functional role for SPP1 in perivascular cells-to-microglia crosstalk, whereby SPP1 modulates microglia-mediated synaptic engulfment in mouse models of AD.
