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result(s) for
"Daugherty, Stephanie"
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Functional roles for PIEZO1 and PIEZO2 in urothelial mechanotransduction and lower urinary tract interoception
by
Dalghi, Marianela G.
,
Ruiz, Wily G.
,
Beckel, Jonathan M.
in
Adenosine Triphosphate - metabolism
,
Amino acids
,
Animals
2021
The mechanisms that link visceral mechanosensation to the perception of internal organ status (i.e., interoception) remain elusive. In response to bladder filling, the urothelium releases ATP, which is hypothesized to stimulate voiding function by communicating the degree of bladder fullness to subjacent tissues, including afferent nerve fibers. To determine if PIEZO channels function as mechanosensors in these events, we generated conditional urothelial Piezo1-, Piezo2-, and dual Piezo1/2-knockout (KO) mice. While functional PIEZO1 channels were expressed in all urothelial cell layers, Piezo1-KO mice had a limited phenotype. Piezo2 expression was limited to a small subset of superficial umbrella cells, yet male Piezo2-KO mice exhibited incontinence (i.e., leakage) when their voiding behavior was monitored during their active dark phase. Dual Piezo1/2-KO mice had the most affected phenotype, characterized by decreased urothelial responses to mechanical stimulation, diminished ATP release, bladder hypoactivity in anesthetized Piezo1/2-KO females but not males, and urinary incontinence in both male and female Piezo1/2-KO mice during their dark phase but not inactive light one. Our studies reveal that the urothelium functions in a sex- and circadian rhythm-dependent manner to link urothelial PIEZO1/2 channel-driven mechanotransduction to normal voiding function and behavior, and in the absence of these signals, bladder dysfunction ensues.
Journal Article
Response of dorsal horn neurons in mice to high‐frequency (kHz) biphasic stimulation is not sensitive to local temperature rise
2025
Clinically accepted for treatment of chronic pain 10 kHz‐frequency electric spinal cord stimulation (10 kHz‐SCS) releases more power in tissue compared to conventional low‐frequency (<100 Hz) stimulation due to increased duty cycle. This is equivalent to the release of more heat in a surrounding tissue, which may change the functional state of affected neural elements. In the case of SCS, plausible candidates to be affected by thermal a component of kHz‐frequency electric field stimulation (kHz‐FS) are dorsal column axons and neurons of the superficial layers of the dorsal horn. In this study, we tested the hypothesis that joule heat produced by kHz‐FS modulates neuronal excitability. In slices of the mouse spinal cord, we monitored membrane potential and membrane input resistance in neurons of lamina II during exposure to kHz‐FS. Surprisingly, we found no correlation between temperature rise and changes of membrane parameters. Furthermore, the depolarizing effect of kHz‐FS was always immediate and remained persistent throughout stimulation, whereas rise of temperature was delayed for 1–2 s and reached its saturation level within the following few seconds. Thus, we concluded that the thermal component has an insignificant role in the mechanism of kHz‐FS action.
Journal Article
Characterization of optogenetically activated inhibitory inputs onto cholinergic motor neurons in the spinal dorsolateral nucleus
2025
Inhibitory control of external urethral sphincter motor neurons (EUS‐MNs) in the spinal dorsolateral nucleus (DLN), which corresponds to a portion of Onuf's nucleus in humans, is essential for normal micturition by inducing EUS relaxation during voiding; yet synaptic mechanisms remain poorly characterized. Using neonatal mice P8‐P12, we developed a slicing technique—cutting spinal cords at 150° from the coronal plane (30° from the horizontal plane in the agarose block), for maximizing EUS‐MNs captured per slice. Using transgenic mice co‐expressing channelrhodopsin‐2 in inhibitory interneurons (VGAT‐ChR2) and GFP in cholinergic neurons (ChAT‐GFP), we investigated inhibitory synaptic transmission onto EUS‐MNs. Optogenetic activation evoked robust inhibitory postsynaptic potentials (IPSPs), classified as sustained or transient based on temporal profiles. Pharmacology revealed that sustained IPSPs contained both glycinergic and GABAergic components, while GABAA receptors predominantly mediated transient IPSPs. Strychnine (1 μM) selectively blocked glycinergic transmission, while bicuculline (10 μM) eliminated GABAergic components. Insensitivity to glutamatergic antagonists (CNQX and AP5) confirmed purely inhibitory responses. Our findings demonstrate segregation of inhibitory inputs onto EUS‐MNs, with glycinergic and GABAergic transmission contributing to sustained and transient inhibition, respectively, establishing the methodological foundation for investigating inhibitory circuit dynamics in pathological conditions such as spinal cord injury with deficient inhibitory control.
Journal Article
Role of proNGF/p75 signaling in bladder dysfunction after spinal cord injury
2018
Loss of bladder control is a challenging outcome facing patients with spinal cord injury (SCI). We report that systemic blocking of pro-nerve growth factor (proNGF) signaling through p75 with a CNS-penetrating small-molecule p75 inhibitor resulted in significant improvement in bladder function after SCI in rodents. The usual hyperreflexia was attenuated with normal bladder pressure, and automatic micturition was acquired weeks earlier than in the controls. The improvement was associated with increased excitatory input to the spinal cord, in particular onto the tyrosine hydroxylase-positive fibers in the dorsal commissure. The drug also had an effect on the bladder itself, as the urothelial hyperplasia and detrusor hypertrophy that accompany SCI were largely prevented. Urothelial cell loss that precedes hyperplasia was dependent on p75 in response to urinary proNGF that is detected after SCI in rodents and humans. Surprisingly, death of urothelial cells and the ensuing hyperplastic response were beneficial to functional recovery. Deleting p75 from the urothelium prevented urothelial death, but resulted in reduction in overall voiding efficiency after SCI. These results unveil a dual role of proNGF/p75 signaling in bladder function under pathological conditions with a CNS effect overriding the peripheral one.
Journal Article
Treatment for the Service Member: A Description of Innovative Interventions
by
Daugherty, Stephanie E.
,
Cancio, Leonard
,
Yancosek, Katie
in
Accuracy
,
Adaptation, Physiological
,
Amputation
2008
This article describes advances to the rehabilitation programs at major military medical centers since the onset of operations in Iraq and Afghanistan. The demands on military health care in times of war produce advances in the various rehabilitation professions. This article describes two programs that use new technologies for the care of military patients with devastating injuries to the upper extremity. One project relates to the application of voice-sensitive technology. The other project describes the utilization of virtual reality technology through a Firearm Training System. The article also explains an adaptive sports program and how recreation is part of a robust community reintegration program. Lastly, this article discusses the Center for the Intrepid, which is one of two new amputee care centers built to support the advanced rehabilitation of war-wounded amputees.
Journal Article
Metabolic Reprogramming of Urothelial Carcinoma—A Theragnostic Target for Betulinic Acid
by
Kimura, Shingo
,
Beckel, Jonathan M.
,
Halder, Aratrika
in
Apoptosis
,
Apoptosis - drug effects
,
BCG vaccines
2025
A pivotal role of metabolic reprogramming in urothelial carcinoma is hallmarked by the dependence of two-fold faster proliferation of urothelial carcinoma cell line T24 than benign cell line TRT-HU1 on five-fold higher glucose (basal) 16 mM vs. 3 mM in McCoy’s 5A media and Keratinocyte Serum Free media, respectively. Here, we report that an additional 10% increase to 17.6 mM and 3.3 mM glucose significantly shortens the doubling time by 3 h and 1 h for T24 and TRT-HUI, respectively. T24 grown at 17.6 mM glucose lowers the confocal localization of the fatty acid mimetic, Betulinic Acid (BA) conjugated to FITC (BA-FITC) with Mito Tracker Red (mitochondrial marker), which doubles the IC50 of BA and BA-FITC by lowering cell cycle arrest in the G0/G1 phase from 54.2% to 43.8% and caspase-3/7 mediated apoptosis and by reversing caspase-3, p53, PTEN, GAPDH, and XIAP gene expression induced by BA in T24 grown at basal glucose (16 mM). Besides slowing the glycogen and pH decline of T24 at basal glucose, BA exhibited an eight-fold higher IC50 than Mitomycin C (MC) on TRT-HU1 by not mimicking the glucose-insensitive cycle arrest and apoptosis of MC. Overall, the glucose sensitivity of the lower IC50 of BA-FITC and BA on T24 vs. TRT-HU1 supports the safety of BA conjugates for theragnostic purposes.
Journal Article
Sports as Occupation: Walter Reed Army Medical Center's Adaptive Sports Program
2007
Trade Publication Article
Monocyte tissue factor–dependent activation of coagulation in hypercholesterolemic mice and monkeys is inhibited by simvastatin
by
Temel, Ryan E.
,
Mackman, Nigel
,
Williams, Julie C.
in
Animals
,
Anticholesteremic Agents - pharmacology
,
Apheresis
2012
Hypercholesterolemia is a major risk factor for atherosclerosis. It also is associated with platelet hyperactivity, which increases morbidity and mortality from cardiovascular disease. However, the mechanisms by which hypercholesterolemia produces a procoagulant state remain undefined. Atherosclerosis is associated with accumulation of oxidized lipoproteins within atherosclerotic lesions. Small quantities of oxidized lipoproteins are also present in the circulation of patients with coronary artery disease. We therefore hypothesized that hypercholesterolemia leads to elevated levels of oxidized LDL (oxLDL) in plasma and that this induces expression of the procoagulant protein tissue factor (TF) in monocytes. In support of this hypothesis, we report here that oxLDL induced TF expression in human monocytic cells and monocytes. In addition, patients with familial hypercholesterolemia had elevated levels of plasma microparticle (MP) TF activity. Furthermore, a high-fat diet induced a time-dependent increase in plasma MP TF activity and activation of coagulation in both LDL receptor-deficient mice and African green monkeys. Genetic deficiency of TF in bone marrow cells reduced coagulation in hypercholesterolemic mice, consistent with a major role for monocyte-derived TF in the activation of coagulation. Similarly, a deficiency of either TLR4 or TLR6 reduced levels of MP TF activity. Simvastatin treatment of hypercholesterolemic mice and monkeys reduced oxLDL, monocyte TF expression, MP TF activity, activation of coagulation, and inflammation, without affecting total cholesterol levels. Our results suggest that the prothrombotic state associated with hypercholesterolemia is caused by oxLDL-mediated induction of TF expression in monocytes via engagement of a TLR4/TLR6 complex.
Journal Article