Biology subjects

Willows, J. W.

Publications and source records attributed to Willows, J. W..

5 recordsLinked to original sources

bioRxiv2023

Telomerase reverse transcriptase (TERT)-expressing cells mark a novel stem cell population in the adult mouse brain

Telomerase reverse transcriptase (TERT) is expressed by quiescent adult stem cells (ASC) in numerous adult murine and human tissues, but has never been explored in the adult brain. Here, we demonstrate that TERT+ cells in the adult mouse brain represent a novel population of multipotent ASCs that are localized to numerous classical neuro/gliogenic niches (including the ventricular-subventricular zone, hypothalamus, and olfactory bulb), as well as more recently described regions of adult brain plasticity such as the meninges and choroid plexus. Using a direct-reporter mouse line, we found that TERT+ cells expressed known neural stem cell markers such as Nestin and Sox2, but not markers of committed stem/progenitor cells, nor markers of mature neuronal or glial cells. TERT+ ASCs rarely expressed the proliferation marker Ki67, and in vitro TERT+ cells lost TERT expression when activated by growth factors, together indicating a quiescent phenotype similar to what has been observed in other tissues. When cultured, TERT+ cells behaved like neural stem cells by forming neurospheres, which could proliferate and become more metabolically active once stimulated by growth factors. TERT+ cells were observed in numerous brain niches, particularly near the ventricles and cerebrospinal fluid barriers, but notably, TERT+ cells were never observed in the hippocampus. Lineage tracing of TERT+ cells in adult transgenic mice (mTERTrtTA::oTET-Cre::RosamTmG) revealed large-scale expansion of TERT+ progeny and differentiation to diverse cell types in multiple brain regions. For example, lineage-traced cells expressed markers of mature neurons, oligodendrocytes, astrocytes, ependymal cells, and choroid epithelial cells, thus demonstrating the striking multipotency of this stem cell population in basal tissue turnover of the adult brain. Together, these data demonstrate that TERT+ cells represent a novel population of multipotent stem cells that contribute to basal plasticity and regeneration in the adult mouse brain. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/527879v1_ufig1.gif" ALT="Figure 1"> View larger version (94K): org.highwire.dtl.DTLVardef@94c0dborg.highwire.dtl.DTLVardef@185dborg.highwire.dtl.DTLVardef@1fb1e1borg.highwire.dtl.DTLVardef@17580a7_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2022

The Presence of Myelinated Nerves and Schwann Cells in White Adipose Tissue: Proximity to Synaptic Vesicle Containing Nerve Terminals and Potential Role in BTBR ob/ob Demyelinating Diabetic Neuropathy

Peripheral neuropathy is a pathophysiological state of nerve degeneration and loss of tissue innervation. The most prominent cause of small fiber neuropathy is diabetes which can be demyelinating in nature, but this has not yet been explored in adipose tissue. Both demyelinating neuropathies and axonopathies implicate Schwann cells (SCs), the peripheral glial required for nerve myelination and regeneration after injury. Here, we perform a comprehensive assessment of SCs and myelination patterns of subcutaneous white adipose tissue (scWAT) nerves, including changes that occur with obesity and other imbalanced energy states in mice and humans. We found that mouse scWAT is densely innervated by both myelinated and unmyelinated sensory and sympathetic nerves. Accordingly, scWAT is home to both myelinating and non-myelinating SCs - the greater proportion of which are myelinating. Furthermore, SCs were found closely associated with synaptic vesicle-containing nerve terminals in scWAT. Obese BTBR ob/ob mice exhibit diabetic peripheral neuropathy in scWAT, and display concordant demyelination specific to small fibers, which was also associated with a decrease in the pan-SC marker Sox10 and compensatory increase in Krox20 gene expression. Together this suggests that adipose SCs may be involved in regulating the plasticity or the neuropathy of adipose tissue nerves.

neuroscience↗

bioRxiv2019

Visualization and Analysis of Whole Depot Adipose Tissue Innervation

Little is known about the diversity and function of adipose tissue nerves due, in part, to the inability to effectively visualize the various nerve subtypes residing within these tissues. The tools currently available for researchers to image and quantify adipose tissue innervation are limited and dependent on optical clearing techniques and light sheet microscopy. Here we present a method of tissue processing that uses mechanical force to compress tissue to decrease tissue thickness in the z-axis by expanding it in the x and y-axes whilst leaving cells intact. This has been combined with autofluorescence quenching techniques to permit intact whole tissues to be mounted on slides and imaged on any microscope, with a complementary means to perform whole tissue neurite density quantification. We have included examples of how this technique can be used to further our current knowledge of adipose-nerve communication by characterizing the nerves, nerve-subtypes, and neurovascular interactions within subcutaneous white adipose tissue in mice.

neuroscience↗

bioRxiv2019

Myeloid-secreted BDNF maintains innervation of inguinal adipose in male mice

BackgroundInnervation of adipose tissue is essential for the proper function of this critical metabolic organ. Numerous surgical and chemical denervation studies have demonstrated how maintenance of brain-adipose communication through both sympathetic efferent and sensory afferent nerves helps regulate adipocyte size, cell number, lipolysis, and browning of white adipose tissue. Neurotrophic factors are growth factors that promote neuron survival, regeneration and plasticity, including neurite outgrowth and synapse formation. Peripheral blood immune cells have been shown to be a source of neurotrophic factors in humans and mice. Although a number of immune cells reside in the adipose stromal vascular fraction (SVF), it has remained unclear what roles they play in adipose innervation. We previously demonstrated that adipose immune cells secrete brain derived neurotrophic factor (BDNF). MethodsWe now show that deletion of this neurotrophic factor from the myeloid lineage led to a genetic denervation of inguinal subcutaneous white adipose tissue (scWAT), thereby causing decreased energy expenditure, increased adipose mass, and a blunted UCP1 response to cold stimulation. ResultsWe and others have previously shown that noradrenergic stimulation via cold exposure increases adipose innervation in the inguinal depot. Here we have identified a subset of myeloid cells that home to scWAT upon cold exposure and are Ly6C + CCR2 + Cx3CR1 + monocytes/macrophages that express noradrenergic receptors and BDNF. ConclusionsWe propose that these cold induced neuroimmune cells (CINCs) are key players in maintaining adipose innervation as well as promoting adipose nerve remodeling under noradrenergic stimulation, such as cold exposure.

neuroscience↗

bioRxiv2018

Neuropathy and neural plasticity in the subcutaneous white adipose depot.

The difficulty in obtaining as well as maintaining weight loss, together with the loss of metabolic control in conditions like diabetes and cardiovascular disease, may represent pathological situations of inadequate neural communication between the brain and peripheral organs and tissues. Innervation of adipose tissues by peripheral nerves provides a means of communication between the master metabolic regulator in the brain (chiefly the hypothalamus), and energy-expending and energy-storing cells in the body (primarily adipocytes). Although chemical and surgical denervation studies have clearly demonstrated how crucial adipose tissue neural innervation is for maintaining proper metabolic health, we have uncovered that adipose tissue becomes neuropathic in various conditions of metabolic dysregulation. Here, utilizing both human and mouse adipose tissues, we present evidence of adipose tissue neuropathy, or loss of innervation, under pathophysiological conditions such as obesity, diabetes, and aging, all of which are concomitant with insult to the adipose organ and metabolic dysfunction. Neuropathy is indicated by loss of nerve fiber protein expression, reduction in synaptic markers, and less neurotrophic factor expression in adipose tissue. Aging-related adipose neuropathy particularly results in loss of innervation around the tissue vasculature. These findings underscore that peripheral neuropathy is not restricted to classic tissues like the skin of distal extremities, and that loss of innervation to adipose may trigger or exacerbate metabolic diseases. In addition, we have demonstrated stimulation of adipose tissue neural plasticity with exercise, cold exposure or neurotrophic factor treatment, which may ameliorate adipose neuropathy and be a potential therapeutic option to re-innervate adipose and restore metabolic health.

neuroscience↗