Biology subjects

Intorcia, A. J.

Publications and source records attributed to Intorcia, A. J..

4 recordsLinked to original sources

bioRxiv2023

Unveiling a Novel Memory Center in Humans: Neurochemical Identification of the Nucleus Incertus, a Key Pontine Locus Implicated in Stress and Neuropathology

BackgroundThe nucleus incertus (NI) was originally described by Streeter in 1903, as a midline region in the floor of the fourth ventricle (4V) of the human brain with an unknown function. More than a century later, the neuroanatomy of the NI including its forebrain target regions has been described in lower vertebrates, but not in humans. Therefore, we examined the neurochemical anatomy of the human NI using several markers, including the neuropeptide, relaxin-3 (RLN3), and began to explore the distribution of the NI-related RLN3 innervation of the hippocampus. MethodsHistochemical staining of serial, coronal sections (30 {micro}m) of control human postmortem pons was conducted to reveal the presence of the NI by detection of immunoreactivity (IR) for the neuronal marker, microtubule-associated protein-2 (MAP2), two markers present in rat NI, glutamic acid dehydrogenase (GAD)-65/67 and corticotrophin releasing hormone receptor 1 (CRHR1), and RLN3, which is highly expressed in a major population of NI neurons in diverse species. RLN3 and vesicular GABA transporter 1 (vGAT1) mRNA was detected by multiplex, fluorescence in situ hybridization. Postmortem pons sections containing the NI from an Alzheimers disease (AD) case were immunostained for phosphorylated-tau (AT8 antibody), to explore potential relevance to neurodegenerative diseases. Lastly, sections of human hippocampus were stained to detect RLN3-IR and somatostatin (SST)-IR, as SST is expressed in interneurons targeted by RLN3 projections in rodents. ResultsIn the dorsal, anterior-medial region of the human pons, neurons containing RLN3- and MAP2-IR, and RLN3/vGAT1 mRNA-positive neurons were observed in an anatomical pattern consistent with that of the NI in other species. GAD65/67- and CRHR1-immunopositive neurons were also detected within this area. Furthermore, RLN3- and AT8-IR were co-localized within NI neurons of an AD subject. Lastly, RLN3-IR was detected in neurons within the CA1, CA2, CA3, and DG areas of the hippocampus, in the absence of RLN3 mRNA. In the DG, RLN3- and SST-IR were co-localized in a small population of neurons. ConclusionsAspects of the anatomy of the human NI are shared across species, including a population of RLN3-expressing neurons and a RLN3 innervation of the hippocampus. Accumulation of phosphorylated-tau in the NI suggests its possible involvement in AD pathology. Further characterization of the neurochemistry of the human NI will increase our understanding of its functional role in health and disease. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=75 SRC="FIGDIR/small/556922v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@f4c439org.highwire.dtl.DTLVardef@17e85f5org.highwire.dtl.DTLVardef@18ca7faorg.highwire.dtl.DTLVardef@168246c_HPS_FORMAT_FIGEXP M_FIG Graphical Abstract Created with BioRender.com C_FIG

neuroscience↗

bioRxiv2022

The tau oligomer antibody APNmAb005 detects early-stage pathological tau enriched at synapses and rescues neuronal loss in long-term treatments

Numerous tau immunotherapies are being developed against Alzheimers disease (AD), but it has been challenging to specifically target early-stage tau aggregates using conformation-dependent antibodies. Here, we report a monoclonal antibody, APNmAb005, that recognized a conformational epitope associated with tau oligomers. In AD brain extracts, mAb005 preferentially recognized oligomeric tau in the synapse over monomeric tau in the cytosol. In the prefrontal cortex and hippocampus, mAb005 immunoreactivity was strongly present in early-stage AD but surprisingly diminished in late-stage AD (Braak stage VI). mAb005 also recognized aggregates in 3R tauopathies (Picks disease) and 4R tauopathies (corticobasal degeneration and progressive supranuclear palsy), including those in astrocytes and oligodendrocytes. In rTg4510 mice (P301L tau), mAb005 immunoreactivity first appeared in distal neurites but much later in neuronal somas. Thus, the mAb005 epitope appears to be associated with early-stage oligomers of tau (esoTau) that accumulate around synapses in AD, which is also detectable in both 3R and 4R tauopathies. In cellular uptake models of tauopathy transmission, mAb005 blocked the formation of intracellular inclusions induced by incubation with rTg4510 mouse brain extracts. Long-term treatments with mAb005 in rTg4510 mice partially rescued synaptic and neuronal loss in the hippocampus without promoting overall tau clearance. Our data suggest that immunotherapies targeting esoTau enriched around synaptic sites may alleviate tau toxicity against synapses and neurons, which may be a promising treatment strategy against AD. One Sentence SummaryA tau-conformer antibody recognizing synaptic oligomers and 3R, 4R, and mixed aggregates in humans rescues neuronal loss in mouse tauopathy models.

neuroscience↗

bioRxiv2019

Severe Hyposmia Distinguishes Neuropathologically Confirmed Dementia with Lewy Bodies from Alzheimer’s Disease Dementia

Due to the absence of core clinical features, many subjects with neuropathologically-confirmed dementia with Lewy bodies (DLB) are never diagnosed as such during life. Most of these are diagnosed with Alzheimers disease dementia (ADD) or unspecified dementia. Unrecognized DLB therefore is a critical impediment to clinical studies and treatment trials of both ADD and DLB. There are numerous published studies that suggest that olfactory function tests may be able to differentiate some neurodegenerative conditions from each other and from normal subjects, but there are very few studies with neuropathological confirmation of diagnosis. We compared University of Pennsylvania Smell Identification Test (UPSIT) results in 209 subjects: 1) 29 concurrently meeting intermediate or high consensus clinicopathological criteria for both DLB and ADD 2) 96 meeting criteria for ADD without DLB 3) 84 control subjects that were non-demented and without parkinsonism at death. The DLB subjects had significantly lower (one-way ANOVA p < 0.0001, pairwise Bonferroni p < 0.05) first and mean UPSIT scores (13.7 and 13.2) than ADD (23.3 and 22.2) or controls (29.6 and 28.9). For subjects with first and mean UPSIT scores less than 20 and 17, respectively, Firth logistic regression analysis, adjusted for age, gender and mean MMSE score, conferred statistically significant odds ratios of 17.5 and 18.0 for predicting a DLB vs ADD diagnosis, as compared to 3.3 for the presence or absence of visual hallucinations throughout the clinical observation period. To our knowledge, this is the largest study to date comparing olfactory function in subjects with neuropathologically confirmed DLB and ADD. Olfactory function testing may be a convenient and inexpensive strategy for enriching dementia studies or clinical trials with DLB subjects, or conversely, reducing the inclusion of DLB subjects in ADD studies or trials.

neuroscience↗

bioRxiv2019

A Modification of the Bielschowsky Silver Stain for Alzheimer Neuritic Plaques: Suppression of Artifactual Staining by Pretreatment with Oxidizing Agents

The Bielschowsky silver method has been the most commonly-used histological stain for demonstrating the neuritic plaques and neurofibrillary tangles that define Alzheimers disease (AD). The stain has been critical to providing a common measure allowing large clinicopathological correlation studies that have demonstrated statistically significant and independent contributions of both lesion types to cognitive impairment and dementia. The continuing relevance of neuritic plaques, and the Bielschowsky stain as the method of choice for their demonstration, is also indicated by its use as the US Food and Drug Administration (FDA) \"standard of truth\" for autopsy confirmation of the validity of PET amyloid imaging agents. Many modifications of the Bielschowsky stain have been published but it is still known to frequently generate artifactual staining that at times mimics the appearance of amyloid plaques. In this study we found that pretreatment with oxidizing agents prior to the initial incubation in silver nitrate eliminates these artifacts and reduces the commonly observed high background staining. This new method may be valuable for Alzheimers disease (AD) researchers and neuropathologists.

neuroscience↗