SUMMARY Our work focused on the studies on the expression and function of transient receptor poten -tial vanilloid subtype 1 ( TRPV1) in the submandibular gland .By using reverse transcription-polymerase chain reaction ( RT-PCR ) , Western blotting , and immunofluorescence , our data demonstrated the expression and distribution characteristics of TRPV 1 in rabbit and human submandibular glands , as well as rat submandibular gland cell line SMG-C6.Furthermore, the possible intracellular signal molecules involved in the TRPV1-modulated saliva secretion were explored .Activation of TRPV1 increased the intracellular Ca2+concentration, upregulated the expression of aquaporin 5 (AQP5), the main transpor-ter that mediate water secretion through transcellular pathway , and led to AQP5 redistribution .Extracel-lular signal-regulated kinase 1/2 ( ERK1/2 ) was involved in the TRPV1-regulated AQP5 content. Besides, TRPV1 activation also modulated the expression , distribution, and function of tight junction protein, and increased paracellular permeability .ERK1/2 and myosin light chain 2 ( MLC2 ) were responsible for the regulation of TRPV1on tight junction properties.Taken together, our work suggested that TRPV1 was a potential target to promote saliva secretion , and activation of TRPV1 might provide a new and safe therapeutic strategy to ameliorate submandibular gland hypofunction .

Transient receptor potential vanilloid subtype 1 (TRPV1) was originally found in sensory neurons. Recently, it has been reported that TRPV1 is expressed in salivary gland epithelial cells (SGEC). However, the physiological role of TRPV1 in salivary secretion remains to be elucidated. We found that TRPV1 is expressed in mouse and human submandibular glands (SMG) and HSG cells, originated from human submandibular gland ducts at both mRNA and protein levels. However, capsaicin (CAP), TRPV1 agonist, had little effect on intracellular free calcium concentration ([Ca2+]i) in these cells, although carbachol consistently increased [Ca2+]i. Exposure of cells to high temperature (>43degrees C) or acidic bath solution (pH5.4) did not increase [Ca2+]i, either. We further examined the role of TRPV1 in salivary secretion using TRPV1 knock-out mice. There was no significant difference in the pilocarpine (PILO)-induced salivary flow rate between wild-type and TRPV1 knock-out mice. Saliva flow rate also showed insignificant change in the mice treated with PILO plus CAP compared with that in mice treated with PILO alone. Taken together, our results suggest that although TRPV1 is expressed in SGEC, it appears not to play any direct roles in saliva secretion via transcellular pathway.
Animals ; Baths ; Calcium ; Capsaicin ; Carbachol ; Epithelial Cells* ; Humans ; Mice ; Mice, Knockout ; Pilocarpine ; RNA, Messenger ; Saliva ; Salivary Glands* ; Sensory Receptor Cells ; Submandibular Gland ; Transcytosis*

Objective:To investigate the effects of low-frequency and high frequency repetitive transcranial magnetic stimulation (rTMS) combined with levodopa and benserazide hydrochloride on mild cognitive impairment in patients with Parkinson disease (PD).Methods:Totally 90 PD patients with mild cognitive impairment who visited from January 2020 to June 2022 were included , and they were divided into a simple drug group ( n=30), drug+ low-frequency group ( n=30), and drug+ high-frequency group ( n=30) according to the order of admission.The patients in the simple drug group were treated with oral levodopa and benserazide hydrochloride, while the patients in drug+ low-frequency and drug+ high-frequency groups were treated with low-frequency or high-frequency rTMS on the basis of oral levodopa and benserazide hydrochloride.Montreal cognitive assessment(MoCA), digital span (DS), Chinese auditory learning test (CALT), the judgment of line orientation test (JLOT) and verbal fluency test (VFT) were used to evaluate the cognitive function of patients before and after 4 weeks of treatment.SPSS 26.0 was used for statistical analysis.The paired t-test was used for intra-group comparison before and after treatment, while one-way ANOVA was used for inter-group comparison. Results:There were no significant differences in MoCA, DS anterograde, DS backward, CALT immediate recall, CALT delayed recall, JLOT, and VFT scores among patients in the simple drug group before and after 4 weeks of treatment( t=-1.157, -0.648, -0.215, -0.290, -0.154, -0.782, -0.960, all P>0.05). After 4 weeks of treatment, MoCA, DS anterograde, DS backward, CALT immediate recall, CALT delayed recall, JLOT and VFT scores in drug+ low-frequency group and drug+ high-frequency group were higher than before treatment (drug+ low frequency group: t=-16.357, -11.379, -7.999, -11.805, -16.624, -15.996, -17.241, all P<0.05; drug+ high-frequency group: t=-25.198, -13.971, -13.904, -25.831, -26.382, -20.108, -15.643, all P<0.05). There were no statistically significant differences in the scores of MoCA, DS anterograde, DS backward, CALT immediate recall, CALT delayed recall, JLOT and VFT among the three groups before treatment (all P>0.05). After treatment, there were statistically significant differences in the scores of MoCA, DS anterograde, DS backward, CALT immediate recall, CALT delayed recall, JLOT and VFT among the three groups (simple drug group : (20.37±1.96), (4.37±1.19), (2.80±0.55), (6.93±1.70), (5.17±1.09), (15.50±2.69), (10.73±1.55); drug+ low-frequency group: (23.83±2.32), (5.87±0.94), (3.87±0.73), (9.17±1.74), (8.13±1.50), (20.77±2.19), (13.30±1.73); drug+ high-frequency group: (27.17±1.64), (6.73±1.01), (4.80±0.81), (11.20±2.06), (10.03±1.54), (25.17±3.14), (15.87±2.05)) (all P<0.05). Further analysis showed that both the drug+ low-frequency and drug+ high-frequency groups had higher scores than the simple drug group, and the drug+ high-frequency group had higher scores than the drug+ low-frequency group(all P<0.05). Conclusion:The combination of drug+ low-frequency or drug+ high-frequency rTMS and drug therapy can help improve cognitive function in patients with PD, and the efficacy of drug+ high-frequency rTMS may be more significant, which provides a new therapeutic idea for clinical treatment of patients with PD.

Autologous submandibular gland (SMG) transplantation has been proved to ameliorate the discomforts in patients with severe keratoconjunctivitis sicca. The transplanted glands underwent a hypofunctional period and then restored secretion spontaneously. This study aims to investigate whether autonomic nerves reinnervate the grafts and contribute to the functional recovery, and further determine the origin of these nerves. Parts of the transplanted SMGs were collected from the epiphora patients, and a rabbit SMG transplantation model was established to fulfill the serial observation on the transplanted glands with time. The results showed that autonomic nerves distributed in the transplanted SMGs and parasympathetic ganglionic cells were observed in the stroma of the glands. Low-dense and unevenly distributed cholinergic axons, severe acinar atrophy and fibrosis were visible in the patients' glands 4-6 months post-transplantation, whereas the cholinergic axon density and acinar area were increased with time. The acinar area or the secretory flow rate of the transplanted glands was statistically correlated with the cholinergic axon density in the rabbit model, respectively. Meanwhile, large cholinergic nerve trunks were found to locate in the temporal fascia lower to the gland, and sympathetic plexus concomitant with the arteries was observed both in the adjacent fascia and in the stroma of the glands. In summary, the transplanted SMGs are reinnervated by autonomic nerves and the cholinergic nerves play a role in the morphological and functional restoration of the glands. Moreover, these autonomic nerves might originate from the auriculotemporal nerve and the sympathetic plexus around the supplying arteries.
Animals ; Autonomic Pathways ; growth & development ; Fascia ; innervation ; Female ; Humans ; Keratoconjunctivitis Sicca ; surgery ; Male ; Models, Animal ; Rabbits ; Recovery of Function ; Secretory Rate ; Submandibular Gland ; innervation ; transplantation ; Transplantation, Autologous

Immunoglobulin G4-related sialadenitis (IgG4-RS) is an immune-mediated fibro-inflammatory disease and the pathogenesis is still not fully understood. The aim of this study was to explore the role and mechanism of interleukin-13 (IL-13) in the cellular senescence during the progress of IgG4-RS. We found that the expression of IL-13 and IL-13 receptor α1 (IL-13Rα1) as well as the number of senescent cells were significantly higher in the submandibular glands (SMGs) of IgG4-RS patients. IL-13 directly induced senescence as shown by the elevated activity of senescence-associated β-galactosidase (SA-β-gal), the decreased cell proliferation, and the upregulation of senescence markers (p53 and p16) and senescence-associated secretory phenotype (SASP) factors (IL-1β and IL-6) in SMG-C6 cells. Mechanistically, IL-13 increased the level of phosphorylated signal transducer and activator of transcription 6 (p-STAT6) and mitochondrial-reactive oxygen species (mtROS), while decreased the mitochondrial membrane potential, ATP level, and the expression and activity of superoxide dismutase 2 (SOD2). Notably, the IL-13-induced cellular senescence and mitochondrial dysfunction could be inhibited by pretreatment with either STAT6 inhibitor AS1517499 or mitochondria-targeted ROS scavenger MitoTEMPO. Moreover, IL-13 increased the interaction between p-STAT6 and cAMP-response element binding protein (CREB)-binding protein (CBP) and decreased the transcriptional activity of CREB on SOD2. Taken together, our findings revealed a critical role of IL-13 in the induction of salivary gland epithelial cell senescence through the elevated mitochondrial oxidative stress in a STAT6-CREB-SOD2-dependent pathway in IgG4-RS.
Cellular Senescence/genetics* ; Humans ; Immunoglobulin G/metabolism* ; Interleukin-13/pharmacology* ; Mitochondria/metabolism* ; Sialadenitis/metabolism*