Burd E, Attari M, Smith C, Bunyak F, Lever, T, Nichols N (2025) Genioglossus sarcomere and mitochondria morphology in a rodent model of hypoglossal motor neuron death. Am Physiol Soc 40(S1) doi: 10.1152/physiol.2025.40.S1.0879
Objective: To develop a novel rodent model using intralingual injections of cholera toxin B conjugated to saporin (CTB-SAP) to induce targeted loss of XII LMNs and XII motor output
Summary: Authors hypothesized that XII LMN loss leads to degenerative changes in genioglossus sarcomere and mitochondria morphology in CTB-SAP rats. Ultrastructural changes in genioglossus sarcomere and mitochondria morphology were studied. The preliminary data suggests a dysregulation of sarcomere ultrastructure, particularly Z-lines, and a significant increase in mitochondrial perimeter and maximum Feret’s diameter in CTB-SAP rats vs. controls, consistent with degenerative changes and a potential in flammatory response in genioglossus muscle cells following the loss of XII LMNs.
Usage: Intralingual injection of adult male rats with CTB-SAP (IT-14)
Lewis R, Smith C, Burd E, Nichols N (2025) Phrenic motor nucleus astrocytic density and morphology in a rodent model of respiratory motor neuron death. Am Physiol Soc 40(S1) doi: 10.1152/physiol.2025.40.S1.1115
Objective: Authors hypothesized that astrocytic density would be increased and astrocytic morphology would be altered in the phrenic motor nucleus over the course of motor neuron death in CTB-SAP rats vs. controls.
Summary: The number of astrocytes was significantly increased in CTB-SAP-treated rats. Furthermore, an astrocytic morphological analysis revealed that CTB-SAP rats have significantly increased branch number, number of endpoints, filament volume, and number of intersections, as well as significantly decreased branch volume and branch length inside the phrenic motor nucleus. Additionally, astrocytic number in the non-phrenic motor nucleus region immediately outside of the phrenic motor nucleus was significantly increased while branch length was significantly decreased in CTB-SAP treated rats. Collectively, these findings are indicative of a reactive morphological state in the phrenic motor nucleus in CTB-SAP rats and suggest that astrocytes may also be an origin of TNF-α to impact phrenic plasticity and ultimately breathing.
Usage: Intrapleural injection of CTB-SAP (IT-14) in rat
Keilholz A, Henry J, Osman K, Smith C, Haxton C, Ozden I, Lever T, Nichols N (2025) Impact of TrkB receptor modulation on tongue exercise-induced plasticity in an inducible rodent model of hypoglossal (xii) motor neuron death. Am Physiol Soc 40(S1) doi: 10.1152/physiol.2025.40.S1.0788
Objective: Authors hypothesized that the source of tongue exercise-induced plasticity in CTB-SAP rats arises from a BDNF- dependent pathway to preserve upper airway function.
Summary: Authors targeted tropomyosin receptor kinase B (TrkB) by delivery of either a TrkB receptor antagonist (ANA-12) or vehicle (veh; 50:50 DMSO+aCSF) into the XII nucleus of the brainstem in adult male rats for the following groups: 1) control+sham exercise+veh 2) CTB-SAP+exercise+veh 3)CTB-SAP+exercise+ANA-12. The effect of TrkB receptor inhibition on tongue exercise-induced plasticity was assessed by conducting behavioral assays. The findings suggest that CTB-SAP+exercise+ANA-12 rats have decreased lick force/rate vs. CTB-SAP+/-exercise+/-veh rats as well as control +/-exercise+/-veh rats.
Usage: Intralingual injection of CTB-SAP (IT-14) in rat
Kozlova E, Lam A, Alam S, Shum J, Denys M, Berdasco C, de-Lartigue G, Curras-Collazo M (2025) Do CCKA receptor containing vagal afferent neurons mediate gut-brain inflammatory signals?. Am Physiol Soc 40(S1) doi: 10.1152/physiol.2025.40.S1.2035
Objective: To investigate whether CCKA receptor, containing vagal afferent neurons (VANs), mediate gut-brain inflammatory signaling and contribute to the systemic immune response following an LPS challenge.
Summary: This abstract reports that ablation of CCKAR+ VANs via CCK-SAP reduced LPS-induced IL-6 levels and brain c-Fos expression, indicating a blunted inflammatory response. These findings support the role of CCKAR+ VANs in gut-brain immune signaling and their potential as therapeutic targets.
Usage: CCK-SAP (IT-31) was bilaterally injected into the nodose ganglia (250 nL, 250 ng/μL) to ablate CCKA receptor–expressing vagal afferents.
Janes TA, Parra Sanchez AS, Cardani S, Pagliardini S (2025) Progestin infusion into the hypothalamus of CO2-chemoreflex impaired female rats enhances the hypercapnic ventilatory response. Am Physiol Soc 40(S1) doi: 10.1152/physiol.2025.40.S1.1430
Objective: Authors hypothesized that etonogestrel (ETO) infusion into the dorsomedial hypothalamus (DMH) would elicit CO2-chemo reflex recovery similar to that observed in systemically treated female rats.
Summary: The hypothesis was tested by impairing the CO2-chemoreflex in adult female rats by lesioning retrotrapezoid nucleus (RTN) neurons with substance P-conjugated saporin toxin. Preliminary data suggest that ETO induced modest CO2-chemoreflex recovery in rats with moderate-sized RTN lesion by increasing tidal volume and breathing frequency, while hypoxic ventilation was unaffected. In rats with large RTN lesion, no restorative effect was observed. These data suggest a potential ETO-induced compensatory role for DMH neurons following central CO2-chemoreflex impairment but do not rule out contributions from other brainstem nuclei based on previous systemic ETO administration.
Usage: The CO2-chemoreflex was impaired in adult female Sprague-Dawley rats by lesioning RTN neurons with substance P-saporin toxin (SP-SAP).
Shibata Y, Matsumoto Y, Kohno K, Nakashima Y, Tsuda M (2025) Microgliosis in the spinal dorsal horn early after peripheral nerve injury is associated with damage to primary afferent aβ-fibers. Cells 14(9):666. doi: 10.3390/cells14090666 PMID: 40358190
Objective: To investigate the spatial relationship between microgliosis and the projections of injured nerves by generating mice that had expressed tdTomato in the fourth lumbar dorsal root ganglion (L4-DRG) neurons via intra-L4-spinal nerve (SpN) injection of adeno-associated viral vectors.
Summary: After transection of the L4-SpN, authors found that microgliosis in the SDH selectively occurred in the innervation territories of the injured primary afferent fibers. However, denervating transient receptor potential vanilloid 1 (TRPV1)-expressing primary afferent fibers in theSDH through intrathecal injection of capsaicin did not trigger microgliosis, nor did it influence the microgliosis induced by L4-SpN injury. Conversely, pharmacological damage to myelinated DRG neurons, including Aβ-fibers, was sufficient to induce microgliosis. Furthermore, L4-SpN injury also induced microgliosis in the gracile nucleus, which primarily receives innervation from Aβ-fibers. These findings suggest that microgliosis in the SDH shortly after peripheral nerve injury is predominantly associated with damage to primary afferent Aβ-fibers.
Usage: WT mice were injected with saporin into the L4-SpN, administering 400 nL of saporin solution [saporin conjugated with cholera toxin B subunit (CTB-SAP), isolectin B4 (IB4-SAP),and unconjugated saporin (Ctrl-SAP)]
Hung LY, Alves ND, Del Colle A, Talati A, Najjar SA, Bouchard V, Gillet V, Tong Y, Huang Z, Browning KN, Hua J, Liu Y, Woodruff JO, Juarez D, Medina M, Posner J, Tonello R, Yalcinkaya N, Israelyan N, Ringel R, Yang L, Leong KW, Yang M, Sze JY, Savidge T, Gingrich J, Shulman RJ, Gershon MD, Ouellet A, Takser L, Ansorge MS, Margolis KG (2025) Intestinal epithelial serotonin as a novel target for treating disorders of gut-brain interaction and mood. Gastroenterology 168(4):754-768. doi: 10.1053/j.gastro.2024.11.012 PMID: 39672518
Objective: To investigate how intestinal epithelial serotonin influences mood and gastrointestinal function, and to identify gut-targeted therapies for mood disorders and disorders of gut-brain interaction (DGBI).
Summary: Selective deletion of the serotonin transporter (SERT) from the intestinal epithelium reduced anxiety- and depression-like behaviors in mice without affecting gut motility or cognition. These effects were dependent on afferent vagal signaling. Conversely, depleting intestinal serotonin increased anxiety. A human birth cohort study linked in utero SSRI/SNRI exposure to a higher risk of functional constipation, supporting a gut-brain role in DGBI.
Usage: CCK-SAP (IT-31) was bilaterally injected into the nodose ganglia, and after one week, tests of anxiety and depression were performed.
Griesgraber MJ, Coolen LM, Onslow KM, Corey JR, Rice RE, Aerts EG, Bowdridge EC, Hardy SL, Lehman MN, Goodman RL, Hileman SM (2025) Critical role of arcuate nucleus kisspeptin and Kiss1R in regulation of the ovine luteinizing hormone surge. J Neuroendocrinol e70010. doi: 10.1111/jne.70010 PMID: 40033679
Objective: To examine the functional role of arcuate nucleus (ARC) dynorphin-containing (KNDy) and kisspeptin (Kiss) 1R-containing neurons in ovine luteinizing hormone (LH) surge secretion via injection of saporin-ligand conjugates (SAP) to ablate these neural populations.
Summary: NKB-SAP injections significantly reduced the percentage of ARC Kiss1 (~65% decrease) cells compared to control animals, and a surge-like increase of LH was prevented in ewes with the greatest degree of Kiss1 cell ablation. Kiss-SAP injections had no effect on Kiss1 cell percentage or ARC Kiss1R cell number compared to controls. However, Kiss-SAP injections consistently and robustly decreased LH surge amplitude, with 80% of Kiss-SAP-treated ewes failing to generate a surge. These results support the conclusion that KNDy neurons contribute significantly to the ovine LH surge, while ARC Kiss1R neurons appear to be necessary for a functional surge to occur in sheep.
Usage: Saporin conjugates, NKB-SAP (IT-63) and Kisspeptin-SAP (IT-102) were injected at 700 ng/μL.
Objective: To determine if local reactivation of antigen-specific oral CD8+ TRM exacerbates ligature-induced periodontitis (LIP) in mice.
Summary: Topical application of virus-mimicking peptides during LIP increased alveolar bone loss, enhanced gingival and cervical lymph node inflammation, and upregulated gingival genes linked to innate immunity and cytotoxicity. Depleting CD103+ CD8+ TRM with αCD103-SAP prior to LIP prevented disease exacerbation, implicating these cells in periodontitis pathology.
Usage: Anti-CD103-SAP (IT-50) was administered in PBS at 5 μg (day -4), 2 μg (day 0), and 2 μg (day +4) relative to LIP induction.
Dib C, Queenan J, Willner H, Swartzrock L, Charlesworth C, Denis M, Davis J, Nakauchi H, Liu DR (2025) Combining hsc base-editing with anti-cd117 antibody conditioning to correct severe combined immunodeficiency disorder in a novel mouse model. Transplantation and Cellular Therapy 31(2):S253-S354. doi: 10.1016/j.jtct.2025.01.385
Objective: To test whether base-edited hematopoietic stem cells (HSPCs) combined with non-genotoxic antibody conditioning can correct severe combined immunodeficiency (SCID) in a novel Rag2 mutant mouse model.
Summary: Base-editing delivered via engineered virus-like particles successfully corrected Rag2 mutations in HSPCs, which restored lymphocyte development following transplantation. Conditioning with an Anti-CD117-Saporin conjugate enabled efficient engraftment without irradiation toxicity, demonstrating a safer strategy for SCID treatment.
Usage: Mice were conditioned with Anti-CD117-SAP (IT-83) at 1.5 mg/kg intravenously prior to transplantation of base-edited or wild-type HSPCs.
