bioRxiv Science⌕ Search

bioRxiv · 10.1101/2023.01.20.524921

Vascular and neural transcriptomics reveal stage-dependent pathways to inflammation and cognitive dysfunction in a rat model of hypertension

Abstract

Chronic arterial hypertension causes cerebral microvascular dysfunction and doubles dementia risk in aging. However, cognitive health preservation by therapeutic blood pressure lowering alone is limited and depends on disease duration, the degree of irreversible tissue damage and whether microvascular function can be restored. This study aimed to understand molecular and cellular temporo-spatial pathomechanisms in the course of hypertension. We investigated the effects of initial, early chronic and late chronic hypertension in the frontal brain of rats by applying behavioral tests, histopathology, immunofluorescence, FACS, microvascular/neural tissue RNA sequencing as well as 18F-FDG PET imaging. Chronic hypertension caused frontal brain-specific behavioral deficits. Our results highlight stage-dependent responses to continuous microvascular stress and wounding by hypertension. Early responses included a fast recruitment of activated microglia to the blood vessels, immigration of peripheral immune cells, blood-brain-barrier leakage and an energy-demanding hypermetabolic state. Vascular adaptation mechanisms were observed in later stages and included angiogenesis and vessel wall strengthening by upregulation of cellular adhesion molecules and extracellular matrix. Additionally, we identified late chronic accumulation of Igfbp-5 in the brains of hypertensive rats, which is also a signature of Alzheimers dementia and attenuates protective Igf-1 signaling. Our study advances the knowledge of involved pathomechanisms and highlights the stage-dependent nature of hypertensive pathobiology. This groundwork might be helpful for basic and clinical research to identify stage-dependent markers in the human disease course, investigate stage-dependent interventions besides blood pressure lowering and better understand the relationship between poor vascular health and neurodegenerative diseases.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Ulbrich, P., Morton, L., Briese, M., Laemmlin, N., Mattern, H., Hasanuzzaman, M., Westhues, M., Khoshneviszadeh, M., Appenzeller, S., Guendel, D., Toussaint, M., Brust, P., Kniess, T., Oelschlegel, A., Goldschmidt, J., Meuth, S., Heinze, H. J., Vielhaber, G. D., Vielhaber, S., Becker, A., Dityatev, A., Jandke, S., Sendtner, M., Dunay, I., Schreiber, S.. 2023-01-21. Vascular and neural transcriptomics reveal stage-dependent pathways to inflammation and cognitive dysfunction in a rat model of hypertension. https://doi.org/10.1101/2023.01.20.524921

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

Novel Tau Interaction Partners as Potential Biomarkers and Therapeutic Targets in Neurodegenerative Diseases

Alzheimers disease is a progressive neurodegenerative disorder leading to cognitive decline and ultimately death. One of the main hallmarks of this disease is the accumulation of pathological tau protein into neurofibrillary tangles. To better understand these pathological mechanisms, it is essential to characterize the tau protein interactome in health and disease. In this study, we performed a yeast two-hybrid screening using a human brain cDNA library, from which we identified 15 novel tau-interacting proteins that bind to full-length human tau, or its fragments: the N-terminus, microtubule-binding domain, or C-terminus. We subsequently validated these novel interactions using in vitro co-immunoprecipitation and colocalization assays with both physiological and pathological tau isoforms. Furthermore, their interactions with the human tau protein were analyzed using surface plasmon resonance. Finally, an in silico interactome analysis of these newly discovered tau-binding partners revealed several additional interactors that can link them to downstream processes critical to neurodegenerative pathways Our findings offer fresh insights into tau biology and highlight novel targets for therapeutic intervention and biomarker development.

neuroscience↗

Early visual cortex is not functionally necessary for temporal attention: A TMS study

Temporal attention enhances the selective processing of information at a specific point in time and improves perception. Previous neuroimaging studies investigating its neural mechanisms have either conflated temporal attention with temporal expectation or provided correlational evidence. Thus, whether early visual cortex is functionally necessary for temporal attention remains unknown. Here, we combined psychophysics with transcranial magnetic stimulation (TMS) to examine whether V1/V2 are functionally necessary and play a causal role in temporal attention. Observers performed an orientation-discrimination task in which two consecutive stimuli, T1 and T2, were presented in the periphery, preceded by a precue providing either valid or neutral temporal information. Double-pulse TMS was delivered under four conditions: at T1 (T1-TMS), at T2 (T2-TMS), at both T1 and T2 (both-TMS), or not at all (none-TMS), to assess its effects on temporal attention and the efficacy of the stimulation was verified by pupil size analysis. Behavioral results revealed robust temporal attention benefits on d', reaction time, and the Balanced Integration Score (BIS) across all four TMS conditions, indicating that the benefits of temporal attention were unaffected by occipital TMS. Furthermore, pupil dilation was largest in the both-TMS condition, followed by the T1-TMS and T2-TMS conditions, and smallest in the none-TMS condition, providing physiological verification of the stimulation protocol. Together, these findings reveal the first causal evidence that the early visual cortex is not functionally necessary for endogenous temporal attention.

neuroscience↗

Disentanglement of persistent and dynamic neural substrates of working memory

Competing theories of working memory have alternatively emphasized the importance of persistent and dynamic substrates of this cognitive function. Here, we directly tested these theories by computationally isolating the contributions of persistent and dynamic activity to working memory. We analyzed neuronal population activity recordings in macaques doing match/non-match working memory tasks. We first extracted signatures of persistent and dynamic activity through cue-specific temporal means, temporal principal components, and correlations of activity patterns across task epochs. We then generated synthetic data constrained by these signatures, and decoded cue stimuli from these data, separately from persistent and non-persistent neurons. We found that high decoding performance arose from a nuanced interplay of persistent and dynamic activity. Specifically, we could decode stimuli at empirical or above-chance levels across all tasks only from persistent neurons, but only after constraining correlations of activity patterns across epochs. In this way, we showed distinct roles for persistent and dynamic neuronal activity that help to unify two competing theories of working memory. More broadly, we also advanced computational controlled experiments as a principled framework for adjudicating between competing models of neuronal population activity.

neuroscience↗