• Molecular signatures underlying neurofibrillary tangle susceptibility in Alzheimer’s disease In review Otero-Garcia, M., Xue, Y., Shakouri, T., Yong, Y., Morabito, S., Kawaguchi, R., Swarup, V., Cobos, I. 2019
  • Nav1.1-Overexpressing Interneuron Transplants Restore Brain Rhythms and Cognition in a Mouse Model of Alzheimer's Disease. Neuron Martinez-Losa, M. n., Tracy, T. E., Ma, K. n., Verret, L. n., Clemente-Perez, A. n., Khan, A. S., Cobos, I. n., Ho, K. n., Gan, L. n., Mucke, L. n., Alvarez-Dolado, M. n., Palop, J. J. 2018; 98 (1): 75–89.e5


    Inhibitory interneurons regulate the oscillatory rhythms and network synchrony that are required for cognitive functions and disrupted in Alzheimer's disease (AD). Network dysrhythmias in AD and multiple neuropsychiatric disorders are associated with hypofunction of Nav1.1, a voltage-gated sodium channel subunit predominantly expressed in interneurons. We show that Nav1.1-overexpressing, but not wild-type, interneuron transplants derived from the embryonic medial ganglionic eminence (MGE) enhance behavior-dependent gamma oscillatory activity, reduce network hypersynchrony, and improve cognitive functions in human amyloid precursor protein (hAPP)-transgenic mice, which simulate key aspects of AD. Increased Nav1.1 levels accelerated action potential kinetics of transplanted fast-spiking and non-fast-spiking interneurons. Nav1.1-deficient interneuron transplants were sufficient to cause behavioral abnormalities in wild-type mice. We conclude that the efficacy of interneuron transplantation and the function of transplanted cells in an AD-relevant context depend on their Nav1.1 levels. Disease-specific molecular optimization of cell transplants may be required to ensure therapeutic benefits in different conditions.

    View details for DOI 10.1016/j.neuron.2018.02.029

    View details for PubMedID 29551491

    View details for PubMedCentralID PMC5886814

  • Human von Economo neurons express transcription factors associated with Layer V subcerebral projection neurons. Cerebral cortex (New York, N.Y. : 1991) Cobos, I. n., Seeley, W. W. 2015; 25 (1): 213–20


    The von Economo neurons (VENs) are large bipolar Layer V projection neurons found chiefly in the anterior cingulate and frontoinsular cortices. Although VENs have been linked to prevalent illnesses such as frontotemporal dementia, autism, and schizophrenia, little is known about VEN identity, including their major projection targets. Here, we undertook a developmental transcription factor expression study, focusing on markers associated with specific classes of Layer V projection neurons. Using mRNA in situ hybridization, we found that VENs prominently express FEZF2 and CTIP2, transcription factors that regulate the fate and differentiation of subcerebral projection neurons, in humans aged 3 months to 65 years. In contrast, few VENs expressed markers associated with callosal or corticothalamic projections. These findings suggest that VENs may represent a specialized Layer V projection neuron for linking cortical autonomic control sites to brainstem or spinal cord regions.

    View details for DOI 10.1093/cercor/bht219

    View details for PubMedID 23960210

    View details for PubMedCentralID PMC4318933

  • Inhibitory interneuron deficit links altered network activity and cognitive dysfunction in Alzheimer model. Cell Verret, L. n., Mann, E. O., Hang, G. B., Barth, A. M., Cobos, I. n., Ho, K. n., Devidze, N. n., Masliah, E. n., Kreitzer, A. C., Mody, I. n., Mucke, L. n., Palop, J. J. 2012; 149 (3): 708–21


    Alzheimer's disease (AD) results in cognitive decline and altered network activity, but the mechanisms are unknown. We studied human amyloid precursor protein (hAPP) transgenic mice, which simulate key aspects of AD. Electroencephalographic recordings in hAPP mice revealed spontaneous epileptiform discharges, indicating network hypersynchrony, primarily during reduced gamma oscillatory activity. Because this oscillatory rhythm is generated by inhibitory parvalbumin (PV) cells, network dysfunction in hAPP mice might arise from impaired PV cells. Supporting this hypothesis, hAPP mice and AD patients had decreased levels of the interneuron-specific and PV cell-predominant voltage-gated sodium channel subunit Nav1.1. Restoring Nav1.1 levels in hAPP mice by Nav1.1-BAC expression increased inhibitory synaptic activity and gamma oscillations and reduced hypersynchrony, memory deficits, and premature mortality. We conclude that reduced Nav1.1 levels and PV cell dysfunction critically contribute to abnormalities in oscillatory rhythms, network synchrony, and memory in hAPP mice and possibly in AD.

    View details for DOI 10.1016/j.cell.2012.02.046

    View details for PubMedID 22541439

    View details for PubMedCentralID PMC3375906

  • Step-by-step in situ hybridization method for localizing gene expression changes in the brain. Methods in molecular biology (Clifton, N.J.) Palop, J. J., Roberson, E. D., Cobos, I. n. 2011; 670: 207–30


    RNA in situ hybridization is a powerful technique for examining gene expression in specific cell populations. This method is particularly useful in the central nervous system with its high cellular diversity and dynamic gene expression regulation associated with development, plasticity, neuronal activity, aging, and disease. Standard quantitative techniques such as Western blotting and real-time PCR allow the detection of altered gene or protein expression but provide no information about their cellular source or possible alterations in expression patterns. Here, we describe a step-by-step RNA in situ hybridization method on adult and embryonic brain sections for quantitative neuroscience. We include fully detailed protocols for RNase-free material preparation, perfusion, fixation, sectioning, selection of expressed sequence tag cDNA clones, linearization of cDNA, synthesis of digoxigenin-labeled RNA probes (riboprobes), in situ hybridization on floating and mounted sections, nonradioactive immunohistochemical detection of riboprobes for light and fluorescence microscopy, and double labeling. We also include useful information about quality-control steps, key online sites, commercially available products, stock solutions, and storage. Finally, we provide examples of the utility of this approach in understanding the neuropathogenesis of Alzheimer's disease. With virtually all genomic coding sequences cloned or being cloned into cDNA plasmids, this technique has become highly accessible to explore gene expression profiles at the cellular and brain region level.

    View details for DOI 10.1007/978-1-60761-744-0_15

    View details for PubMedID 20967593

  • Dlx transcription factors promote migration through repression of axon and dendrite growth NEURON Cobos, I., Borello, U., Rubenstein, J. R. 2007; 54 (6): 873–88


    In the mouse telencephalon, Dlx homeobox transcription factors are essential for the tangential migration of subpallial-derived GABAergic interneurons to neocortex. However, the mechanisms underlying this process are poorly understood. Here, we demonstrate that Dlx1/2 has a central role in restraining neurite growth of subpallial-derived immature interneurons at a stage when they migrate tangentially to cortex. In Dlx1-/-;Dlx2-/- mutants, neurite length is increased and cells fail to migrate. In Dlx1-/-;Dlx2+/- mutants, while the tangential migration of immature interneurons appears normal, they develop dendritic and axonal processes with increased length and decreased branching, and have deficits in their neocortical laminar positions. Thus, Dlx1/2 is required for coordinating programs of neurite maturation and migration. In this regard, we provide genetic evidence that in immature interneurons Dlx1/2 repression of the p21-activated serine/threonine kinase PAK3, a downstream effector of the Rho family of GTPases, is critical in restraining neurite growth and promoting tangential migration.

    View details for DOI 10.1016/j.neuron.2007.05.024

    View details for Web of Science ID 000247645600008

    View details for PubMedID 17582329

    View details for PubMedCentralID PMC4921237

  • Mice lacking Dlx1 show subtype-specific loss of interneurons, reduced inhibition and epilepsy. Nature neuroscience Cobos, I. n., Calcagnotto, M. E., Vilaythong, A. J., Thwin, M. T., Noebels, J. L., Baraban, S. C., Rubenstein, J. L. 2005; 8 (8): 1059–68


    Dlx homeodomain transcription factors are essential during embryonic development for the production of forebrain GABAergic interneurons. Here we show that Dlx1 is also required for regulating the functional longevity of cortical and hippocampal interneurons in the adult brain. We demonstrate preferential Dlx1 expression in a subset of cortical and hippocampal interneurons which, in postnatal Dlx1 mutants, show a time-dependent reduction in number. This reduction preferentially affects calretinin(+) (bipolar cells) and somatostatin(+) subtypes (for example, bitufted cells), whereas parvalbumin(+) subpopulations (basket cells and chandelier cells) seem to be unaffected. Cell transplantation analysis demonstrates that interneuron loss reflects cell-autonomous functions of Dlx1. The decrease in the number of interneurons was associated with a reduction of GABA-mediated inhibitory postsynaptic current in neocortex and hippocampus in vitro and cortical dysrhythmia in vivo. Dlx1 mutant mice show generalized electrographic seizures and histological evidence of seizure-induced reorganization, linking the Dlx1 mutation to delayed-onset epilepsy associated with interneuron loss.

    View details for DOI 10.1038/nn1499

    View details for PubMedID 16007083

  • Origins of cortical interneuron subtypes. The Journal of neuroscience : the official journal of the Society for Neuroscience Xu, Q. n., Cobos, I. n., De La Cruz, E. n., Rubenstein, J. L., Anderson, S. A. 2004; 24 (11): 2612–22


    Cerebral cortical functions are conducted by two general classes of neurons: glutamatergic projection neurons and GABAergic interneurons. Distinct interneuron subtypes serve distinct roles in modulating cortical activity and can be differentially affected in cortical diseases, but little is known about the mechanisms for generating their diversity. Recent evidence suggests that many cortical interneurons originate within the subcortical telencephalon and then migrate tangentially into the overlying cortex. To test the hypothesis that distinct interneuron subtypes are derived from distinct telencephalic subdivisions, we have used an in vitro assay to assess the developmental potential of subregions of the telencephalic proliferative zone (PZ) to give rise to neurochemically defined interneuron subgroups. PZ cells from GFP+ donor mouse embryos were transplanted onto neonatal cortical feeder cells and assessed for their ability to generate specific interneuron subtypes. Our results suggest that the parvalbumin- and the somatostatin-expressing interneuron subgroups originate primarily within the medial ganglionic eminence (MGE) of the subcortical telencephalon, whereas the calretinin-expressing interneurons appear to derive mainly from the caudal ganglionic eminence (CGE). These results are supported by findings from primary cultures of cortex from Nkx2.1 mutants, in which normal MGE fails to form but in which the CGE is less affected. In these cultures, parvalbumin- and somatostatin-expressing cells are absent, although calretinin-expressing interneurons are present. Interestingly, calretinin-expressing bipolar interneurons were nearly absent from cortical cultures of Dlx1/2 mutants. By establishing spatial differences in the origins of interneuron subtypes, these studies lay the groundwork for elucidating the molecular bases for their distinct differentiation pathways.

    View details for DOI 10.1523/JNEUROSCI.5667-03.2004

    View details for PubMedID 15028753

  • Defining the nature of human pluripotent stem cell-derived interneurons via single-cell analysis. Stem cell reports Allison, T., Langerman, J., Sabri, S., Otero-Garcia, M., Lund, A., Huang, J., Wei, X., Samarasinghe, R. A., Polioudakis, D., Mody, I., Cobos, I., Novitch, B. G., Geschwind, D. H., Plath, K., Lowry, W. E. 2021


    The specification of inhibitory neurons has been described for the mouse and human brain, and many studies have shown that pluripotent stem cells (PSCs) can be used to create interneurons invitro. It is unclear whether invitro methods to produce human interneurons generate all the subtypes found in brain, and how similar invitro and invivo interneurons are. We applied single-nuclei and single-cell transcriptomics to model interneuron development from human cortex and interneurons derived from PSCs. We provide a direct comparison of various invitro interneuron derivation methods to determine the homogeneity achieved. We find that PSC-derived interneurons capture stages of development prior to mid-gestation, and represent a minority of potential subtypes found in brain. Comparison with those found in fetal or adult brain highlighted decreased expression of synapse-related genes. These analyses highlight the potential to tailor the method of generation to drive formation of particular subtypes.

    View details for DOI 10.1016/j.stemcr.2021.08.006

    View details for PubMedID 34506726

  • Dysregulation of brain and choroid plexus cell types in severe COVID-19. Nature Yang, A. C., Kern, F., Losada, P. M., Agam, M. R., Maat, C. A., Schmartz, G. P., Fehlmann, T., Stein, J. A., Schaum, N., Lee, D. P., Calcuttawala, K., Vest, R. T., Berdnik, D., Lu, N., Hahn, O., Gate, D., McNerney, M. W., Channappa, D., Cobos, I., Ludwig, N., Schulz-Schaeffer, W. J., Keller, A., Wyss-Coray, T. 2021


    Though SARS-CoV-2 primarily targets the respiratory system, patients and survivors can suffer neurological symptoms1-3. Yet, an unbiased understanding of the cellular and molecular processes affected in the brains of COVID-19 patients is still missing. Here, we profile 65,309 single-nucleus transcriptomes from 30 frontal cortex and choroid plexus samples across 14 control (including 1 terminal influenza) and 8 COVID-19 patients. While a systematic analysis yields no molecular traces of SARS-CoV-2 in the brain, we observe broad cellular perturbations which predict that choroid plexus barrier cells sense and relay peripheral inflammation into the brain and show that peripheral T cells infiltrate the parenchyma. We discover COVID-19 disease-associated microglia and astrocyte subpopulations that share features with pathological cell states reported in human neurodegenerative disease4-6. Synaptic signaling of upper-layer excitatory neurons-evolutionarily expanded in humans7 and linked to cognitive function8-are preferentially affected in COVID-19. Across cell types, COVID-19 perturbations overlap with those in chronic brain disorders and reside in genetic variants associated with cognition, schizophrenia, and depression. Our findings and public dataset provide a molecular framework to understand COVID-19 related neurological disease observed now and which may emerge later.

    View details for DOI 10.1038/s41586-021-03710-0

    View details for PubMedID 34153974

  • Hepatic arginase deficiency fosters dysmyelination during postnatal CNS development. JCI insight Liu, X., Haney, J. R., Cantero, G., Lambert, J. R., Otero-Garcia, M., Truong, B., Gropman, A., Cobos, I., Cederbaum, S. D., Lipshutz, G. S. 2019; 4 (17)


    Deficiency of arginase is associated with hyperargininemia, and prominent features include spastic diplegia/tetraplegia, clonus, and hyperreflexia; loss of ambulation, intellectual disability and progressive neurological decline are other signs. To gain greater insight into the unique neuromotor features, we performed gene expression profiling of the motor cortex of a murine model of the disorder. Coexpression network analysis suggested an abnormality with myelination, which was supported by limited existing human data. Utilizing electron microscopy, marked dysmyelination was detected in 2-week-old homozygous Arg1-KO mice. The corticospinal tract was found to be adversely affected, supporting dysmyelination as the cause of the unique neuromotor features and implicating oligodendrocyte impairment in a deficiency of hepatic Arg1. Following neonatal hepatic gene therapy to express Arg1, the subcortical white matter, pyramidal tract, and corticospinal tract all showed a remarkable recovery in terms of myelinated axon density and ultrastructural integrity with active wrapping of axons by nearby oligodendrocyte processes. These findings support the following conclusions: arginase deficiency is a leukodystrophy affecting the brain and spinal cord while sparing the peripheral nervous system, and neonatal AAV hepatic gene therapy can rescue the defects associated with myelinated axons, strongly implicating the functional recovery of oligodendrocytes after restoration of hepatic arginase activity.

    View details for DOI 10.1172/jci.insight.130260

    View details for PubMedID 31484827

  • Dlx1 and Dlx2 Promote Interneuron GABA Synthesis, Synaptogenesis, and Dendritogenesis. Cerebral cortex (New York, N.Y. : 1991) Pla, R. n., Stanco, A. n., Howard, M. A., Rubin, A. N., Vogt, D. n., Mortimer, N. n., Cobos, I. n., Potter, G. B., Lindtner, S. n., Price, J. D., Nord, A. S., Visel, A. n., Schreiner, C. E., Baraban, S. C., Rowitch, D. H., Rubenstein, J. L. 2018; 28 (11): 3797–3815


    The postnatal functions of the Dlx1&2 transcription factors in cortical interneurons (CINs) are unknown. Here, using conditional Dlx1, Dlx2, and Dlx1&2 knockouts (CKOs), we defined their roles in specific CINs. The CKOs had dendritic, synaptic, and survival defects, affecting even PV+ CINs. We provide evidence that DLX2 directly drives Gad1, Gad2, and Vgat expression, and show that mutants had reduced mIPSC amplitude. In addition, the mutants formed fewer GABAergic synapses on excitatory neurons and had reduced mIPSC frequency. Furthermore, Dlx1/2 CKO had hypoplastic dendrites, fewer excitatory synapses, and reduced excitatory input. We provide evidence that some of these phenotypes were due to reduced expression of GRIN2B (a subunit of the NMDA receptor), a high confidence Autism gene. Thus, Dlx1&2 coordinate key components of CIN postnatal development by promoting their excitability, inhibitory output, and survival.

    View details for DOI 10.1093/cercor/bhx241

    View details for PubMedID 29028947

    View details for PubMedCentralID PMC6188538