COVID-19 and vertical transmission: assessing the expression of ACE2/TMPRSS2 in the human fetus and placenta to assess the risk of SARS-CoV-2 infection.

BACKGROUND: Pregnant women have been identified as a potentially at-risk group concerning COVID-19 infection, but little is known regarding the susceptibility of the fetus to infection. Co-expression of ACE2 and TMPRSS2 has been identified as a prerequisite for infection, and expression across different tissues is known to vary between children and adults. However, the expression of these proteins in the fetus is unknown. METHODS: We performed a retrospective analysis of a single cell data repository. The data were then validated at both gene and protein level by performing RT-qPCR and two-colour immunohistochemistry on a library of second-trimester human fetal tissues. FINDINGS: TMPRSS2 is present at both gene and protein level in the predominantly epithelial fetal tissues analysed. ACE2 is present at significant levels only in the fetal intestine and kidney, and is not expressed in the fetal lung. The placenta also does not co-express the two proteins across the second trimester or at term. INTERPRETATION: This dataset indicates that the lungs are unlikely to be a viable route of SARS-CoV2 fetal infection. The fetal kidney, despite presenting both the proteins required for the infection, is anatomically protected from the exposure to the virus. However, the gastrointestinal tract is likely to be susceptible to infection due to its high co-expression of both proteins, as well as its exposure to potentially infected amniotic fluid. TWEETABLE ABSTRACT: This work provides detailed mechanistic insight into the relative protection & vulnerabilities of the fetus & placenta to SARS-CoV-2 infection by scRNAseq & protein expression analysis for ACE2 & TMPRSS2. The findings help to explain the low rate of vertical transmission.

In prenatally diagnosed CPAM, does the affected lobe influence the timing of symptom onset?

PURPOSE: We investigated the relationship between the affected lobe and symptom onset in prenatally diagnosed congenital pulmonary airway malformation (CPAM). METHODS: 53 CPAM patients diagnosed prenatally were reviewed retrospectively by creating 2 groups according to symptom onset. Group Sneo: (symptomatic during the neonatal period; n = 13) and group S > neo: (symptomatic after the neonatal period; n = 40) were compared for type of CPAM, affected lobes, types of symptoms/infections, treatment, duration of follow-up, and histopathology. Requirement for surgery (Sx) was then used to create three subgroups: Sneo + Sx, S > neo + Sx, and Sx-. RESULTS: Some cases had multiple affected lobes. In Sneo, symptoms developed in 55.6%, 50.0%, 0%, 0%, and 36.8% of right upper lobes (RUL), right middle lobes (RML), right lower lobes (RLL), left upper lobes (LUL), and left lower lobes (LLL) diagnosed with CPAM, prenatally. In S > neo, symptoms developed in 0%, 0%, 6.3%, 55.6%, and 33.3% of RUL, RML, RLL, LUL, and LLL diagnosed with CPAM, prenatally. CONCLUSION: In prenatally diagnosed CPAM, RUL and RML lesions are more likely to become symptomatic in neonates, and LUL lesions in infants. Surgery is recommended before the onset of respiratory infections after 1 year of age.

Differences between subtotal corpectomy and laminoplasty for cervical spondylotic myelopathy.

OBJECTIVE: This study aimed to obtain guidelines for choosing between subtotal corpectomy (SC) and laminoplasty (LP) by analysing the surgical outcomes, radiological changes and problems associated with each surgical modality. STUDY DESIGN: A retrospective analysis of two interventional case series. SETTING: Department of Orthopaedic Surgery, Kagawa University, Japan. METHODS: Subjects comprised 34 patients who underwent SC and 49 patients who underwent LP. SC was performed by high-speed drilling to remove vertebral bodies. Autologous strut bone grafting was used. LP was performed as an expansive open-door LP. The level of decompression was from C3 to C7. Clinical evaluations included recovery rate (RR), frequency of C5 root palsy after surgery, re-operation and axial pain. Radiographic assessments included sagittal cervical alignment and bone union. RESULTS: Comparisons between the two groups showed no significant differences in age at surgery, preoperative factors, RR and frequency of C5 palsy. Progression of kyphotic changes, operation time and volumes of blood loss and blood transfusion were significantly greater in the SC (two- or three-level) group. Six patients in the SC group required additional surgery because of pseudoarthrosis, and four patients underwent re-operation because of adjacent level disc degeneration. In the LP group, the problem of elimination of postoperative axial symptoms remains to be solved. CONCLUSIONS: The merit of SC is the low frequency of axial symptoms. One-level SC can be considered to have similar degree of invasiveness as LP. Compared with SC, LP is more suitable for elderly patients with multilevel stenosis.

Radial glia marker expression following experimental intracerebral hemorrhage.

In this study, we examine 3CB2 expression, a marker of radial glia, after intracerebral hemorrhage (ICH). Adult male Sprague-Dawley rats received an intracaudate injection of 100 microL autologous whole blood. Animals were sacrificed, and 3CB2 expression was quantified on Western blot. Single and double labeled immunohistochemistry was used to identify which cells express 3CB2. Neurobehavioral examinations (forelimb placing test) were perfomed as an evaluation of function. By Western blot, 3CB2 was strongly expressed at day 3 and expression persisted for at least 1 month. By immunohistochemistry, 3CB2 immunoreactivity was present in large numbers of astrocytes surrounding the hematoma at day 3 after ICH. At 1 month later, 3CB2 immunoreactivity was co-localized with a neuronal marker (TUC-4). Neurobehavioral function in the 1 month after ICH group was significantly improved compared with that of 3 days after ICH. The ICH-induced 3CB2 expression in astrocytes may reflect an early response of these cells to injury, while the delayed expression in neurons might be a part of the adaptative response to injury, perhaps leading to recovery of neurobehavioral function.

One-dimensional beam ordering of protons in a storage ring.

The ordering of protons has been observed at a new storage ring, S-LSR, at Kyoto University. Abrupt jumps in the momentum spread and the Schottky noise power were observed for protons for the first time at a particle number of approximately 2000, upon applying electron cooling with electron currents of 25, 50, and 100 mA. The transition temperature was 0.17 and 1 meV in the longitudinal and transverse directions, respectively. The transverse temperature of the proton beam was much below that of electrons at the transition, which played an essential role in the ordering of protons.

Role of percutaneous transhepatic obliteration for special types of varices with portal hypertension.

The treatment of special types of varices with portal hypertension has not yet been established. We were able to control 13 cases of special types of varices by percutaneous transhepatic obliteration (PTO). These 13 cases consisted of 2 esophagojejunal varices after total gastrectomy for gastric cancer, 1 stoma varices after abdominoperineal excision for rectal cancer, 2 mesenteric varices with encephalopathy, 1 gastric variceal rupture, 1 gastrorenal and gastroazygos shunt with encephalopathy, 3 giant bar-type esophageal varices, 2 isolated gastric varices with gastropericardiac shunts, and 1 isolated gastric varices with gastrophrenic shunt. The special types of varices were successfully embolized in all cases and there were no complications. We conclude that the PTO is still an effective and safe treatment for special types of varices with portal hypertension.

Altered alpha1-syntrophin expression in myofibers with Duchenne and Fukuyama muscular dystrophies.

Alpha1-syntrophin, a scaffolding adapter and modular protein, is a cytoplasmic component of the dystrophin glycoprotein complex. This study investigated immunohistochemically the expression of alpha1-syntrophin in Duchenne and Fukuyama muscular dystrophies (DMD and FCMD, respectively). Biopsied muscles of five DMD, five FCMD, five normal controls and five disease controls (three myotonic and two facioscapulohumeral dystrophies) were analyzed. Immunoblot analysis showed that anti-alpha1-syntrophin antibody had a decreased reaction in both DMD and FCMD muscle extracts. Biopsied muscle sections and their serial sections were immunostained with rabbit anti-alpha1-syntrophin and rabbit anti-muscle-specific beta-spectrin antibodies, respectively. Immunoreactive patterns of sarcolemma were classified into (i) a continuously positive immunostaining pattern, (ii) a partially positive immunostaining pattern, (iii) a negative immunostaining pattern and (iv) a faint but entire surface positive immunostaining pattern. The group mean percentages of alpha1-syntrophin and beta-spectrin immunonegative myofibers in the DMD group were 39.3% and 10.8%, respectively, while those in the FCMD group were 45.5% and 10.4%, respectively. These values were statistically significant compared with those of disease control and normal control muscles. Thus we found that dystrophin-deficient DMD muscles contained significant numbers of alpha1-syntrophin-positive fibers and significant numbers of alpha1-syntrophin-negative fibers were present in dystrophin-positive muscles of severe muscular dystrophy such as FCMD. Alpha-dystrobrevin immunoreactivity was tested in DMD muscles and appreciable amounts of alpha-dystrobrevin that binds to syntrophin were found in DMD muscle membranes.

Percutaneous transhepatic obliteration for isolated gastric varices with gastropericardiac shunt: case report.

Management of isolated gastric varices with a gastropericardiac shunt (GPS) has not yet been established. We were able to control a case of isolated gastric varices with a GPS by percutaneous transhepatic obliteration (PTO) using a microcatheter. In this case, the main blood drainage route was not a gastrorenal shunt, so transvenous retrograde obliteration could not be performed and PTO using the microcatheter was applied. Percutaneous transhepatic splenic venography revealed that the gastric varices came from the posterior gastric vein and the main drainage route was a GPS. Gastric varices and their blood supply were superselectively embolized using platinum microcoils and absolute ethanol. Portal venous pressure did not change after PTO because the route from the left gastric vein to the azygos venous system was preserved. Computed tomography 7 days after PTO revealed that the gastric varices were completely obliterated by the thrombi. Plasma ammonia level, arterial ketone body ratio, and indocyanine green retention rate at 15 min were improved. We conclude that PTO using a microcatheter is a rational, effective, and safe therapy for isolated gastric varices with a GPS.

Evidence from mucin core protein expression that some Paget's disease on areola can be of extramammary-like histogenesis and part of multisite disease.

Triple extramammary Paget's disease, which consists ordinarily of bilateral axillary and genital lesions, is uncommon. Triple extramammary Paget's disease involving other sites has never been reported, although solitary extramammary Paget's disease can occur at various sites around the body. Erythematous plaques on the areola, axilla and genitalia of a 91-year-old man were surgically removed under the clinical diagnosis of multiple extramammary Paget's disease. Histology revealed that all three lesions consisted of intraepidermal nests of Paget cells and other isolated Paget cells scattered in the epidermis. Although adnexal invasion was observed in the genital lesion, neither intraductal invasion nor underlying breast carcinoma was detected in the areolar lesion. Immunohistochemically, the Paget cells in all lesions expressed simple epithelial cytokeratins (CK8, 18 and 19), mucin (MUC)1 and MUC5AC, but neither CK20 nor MUC2. From the histological findings, the present case was interpreted as triple extramammary Paget's disease rather than synchronous mammary and extramammary Paget's disease. Furthermore, the mucin core protein expression pattern, which was identical to that observed in extramammary Paget's disease, supported the above interpretation.

Diffusion-weighted MRI abnormalities as an early diagnostic marker for Creutzfeldt-Jakob disease.

OBJECTIVE: To evaluate the usefulness of diffusion-weighted MRI (DWI) for the early diagnosis of Creutzfeldt-Jakob disease (CJD). METHODS: Thirty-six consecutive patients (age 56 to 82 years) were enrolled, and 26 were examined by DWI. Nine were definite based on the World Health Organization criteria, and 27 were probable. The percentages of DWI abnormalities, periodic sharp wave complexes (PSWCs) on the EEG, detection of CSF 14-3-3 protein, and increase of CSF neuron-specific enolase (>25 ng/mL) on the first examination were compared. For DWI, 32 patients (age 31 to 84 years) who showed progressive dementia or impaired consciousness served as disease controls. RESULTS: The percentage of DWI abnormalities was 92.3%, of PSWCs 50.0%, of 14-3-3 protein detection 84.0%, and of NSE increase 73.3%. Two of the 32 control subjects were falsely positive on DWI. The sensitivity of DWI was 92.3% (95% CI 74.8 to 99.5%) and specificity 93.8% (95% CI 79.2 to 99.2%). In 17 patients who did not show PSWCs on the first EEG, abnormal DWI findings were still clearly detected. Four patients who were negative for 14-3-3 protein also showed DWI abnormalities. DWI abnormalities were detected as early as at 3 weeks of symptom duration in four patients in whom PSWCs were not yet evident. CONCLUSIONS: DWI can detect characteristic lesions in the majority of patients with CJD regardless of the presence of PSWCs. DWI was the most sensitive test for the early clinical diagnosis of CJD; consideration should be given to its inclusion in the clinical diagnostic criteria of CJD.

Effect of moderate exercise on excess post-exercise oxygen consumption and catecholamines in young women.

AIM: The purpose of this study was to examine the effects of moderate exercise on the magnitude and duration of excess post-exercise oxygen consumption (EPOC) and catecholamine concentrations in 7 young women. METHODS: The subjects performed 30 or 60 minutes of exercise (30-ME and 60-ME, respectively) on separate days at an intensity of 60% of maximal oxygen uptake on a cycle ergometer. The glucose, epinephrine and norepinephrine in the plasma, and free fatty acids and glycerol in the serum were measured at the end of the 60 min of the rest period before each exercise, immediately after the performance of each exercise and 30 min, 1, 2 and 24 h time points after each exercise. RESULTS: EPOC lasted for 46.1+/-25.4 and 116.1+/-79.8 min after the 30- and 60-ME, respectively. Corresponding total EPOC were 2636+/-1125 and 5208+/-1880 ml, respectively. The mean differences were statistically significant (p<0.05 each). The serum free fatty acids significantly increased immediately after the 60-ME. The serum glycerol was significantly increased immediately after the 30-ME and was also significantly increased immediately after and 30 min time point after the 60-ME. The plasma epinephrine and norepinephrine significantly increased immediately after the 30- and 60-ME, respectively. The plasma epinephrine at the 30 min time point after the 60-ME significantly correlated with the magnitude (r=0.955) and duration (r=0.897) of EPOC. Norepinephrine at the 30 min time point after the 60-ME also significantly correlated with the magnitude (r=0.774) of EPOC. CONCLUSION: The results indicate that longer duration exercise results in a greater and longer EPOC, and the plasma catecholamines may possibly contribute to EPOC in young women. Although, the overall magnitude of EPOC is small, if exercise frequency and compliance are strong, some long term benefits may accrue.

Clinical features of Creutzfeldt-Jakob disease with V180I mutation.

The authors describe the clinical features of Creutzfeldt-Jakob disease (CJD) with the causative point mutation at codon 180. The symptoms never started with visual or cerebellar involvement. The patients showed slower progression of the disease compared with sporadic CJD. They never showed periodic sharp and wave complexes in EEG. MRI demonstrated remarkable high-intensity areas with swelling in the cerebral cortex except for the medial occipital and cerebellar cortices. These characteristic MRI findings are an important clue for an accurate premortem diagnosis.

Post-traumatic moderate systemic hypothermia reduces TUNEL positive cells following spinal cord injury in rat.

STUDY DESIGN: A standardized animal model of contusive spinal cord injury (SCI) with incomplete paraplegia was used to test the hypothesis that moderate systemic hypothermia reduces neural cell death. Terminal deoxynucleotidyl transferase [TdT]-mediated deoxyuridine triphosphate [dUTP] nick-end labeling (TUNEL) staining was used as a marker of apoptosis or cell damage. OBJECTIVE: To determine whether or not moderate hypothermia could have a neuroprotective effect in neural cell death following spinal cord injury in rats. SETTING: Kagawa Medical University, Japan. METHODS: Male Sprague-Dawley (SD) rats (n=39) weighing on average 300 g (280-320 g) were used to prepare SCI models. After receiving contusive injury at T11/12, rats were killed at 24 h, 72 h, or 7 days after injury. The spinal cord was removed en bloc and of examined at five segments: 5 and 10 mm rostral to the center of injury, center of injury, and 5 and 10 mm caudal to the center of injury. Rats that received hypothermia (32 degrees C/4 h) were killed at the same time points as those that received normothermia (37 degrees C/3 h). The specimens were stained with hematoxylin and eosin, and subjected to in situ nick-end labeling (TUNEL), a specific method for visualizing cell death in the spinal cord. RESULTS: At 24 h postinjury, TUNEL positive cells (TPC) decreased significantly 10 mm rostral to center of injury in hypothermic animals compared to the normothermia group. At 72 h post-SCI, TPC also decreased significantly at 5 mm rostral, and 5 and 10 mm caudal to the lesion center compared to normothermic animals. At 7 days postinjury, a significant decrease of TPC was observed at the 5 mm rostral and 5 mm caudal sites compared to normothermic animals. CONCLUSION: These results indicate that systemic hypothermia has a neuroprotective effect following SCI by attenuating post-traumatic TPC.

Altered aquaporin 4 expression in muscles of Fukuyama-type congenital muscular dystrophy.

This study was undertaken to investigate the expression of aquaporin 4 (AQP4) in the muscle plasma membrane of children with Fukuyama-type congenital muscular dystrophy (FCMD) at protein and mRNA levels. The biopsied six muscles with FCMD, six histochemically normal muscles and eight disease control muscles were analyzed by means of immunoblots, immunohistochemistry and reverse-transcription polymerase chain reaction (RT-PCR). Immunoblots showed that the band of FCMD muscle extracts stained with anti-AQP4 antibody was faint in comparison with that of normal muscle extracts. The immunohistochemistry revealed that most of the FCMD myofibers showed negative immunostaining with anti-AQP4 antibody, although the partially positive immunostaining of sporadic FCMD myofibers was noted. The immunoreactivity was positive with anti-dystrophin and anti-beta-spectrin antibodies in almost all FCMD myofibers. The quantitative RT-PCR demonstrated that the AQP4 mRNA level of the FCMD muscles was markedly reduced. On the basis of these findings, we conclude that the expression of AQP4 in FCMD myofibers is reduced and the reduced content of AQP4 mRNA in FCMD muscles may be related to the decreased expression of AQP4 at the muscle plasma membrane of FCMD myofibers.

Embryonic intermediate filament, nestin, expression following traumatic spinal cord injury in adult rats.

Precursor cells in the ependyma of the lateral ventricles of adult mammalian brain have been reported in brain, and also in the spinal cord. The present study used antibody to the intermediate filament protein (nestin) as an immunohistochemical marker for neural stem cells and precursor cells in a rat model of spinal cord trauma. Male Sprague-Dawley rats (n=25) had a laminectomy at Thll-Thl2, and spinal cord contusion was created by compression with 30 g of force for 10 min. The rats were killed at 24 h, 1 week and 4 weeks after injury, and four levels of the spinal cord were examined: 5 mm and 10 mm, both rostral and caudal region to the injury center. Time- and region-dependent alterations of nestin immunoreactivity were analyzed. Revealed at 24 h post-injury, 5 mm rostral and caudal to the lesions, nestin expression was observed in ependymal cells and around the hemorrhagic and necrotic lesion located in dorsal spinal cord, peaking at 1 week after injury. Moreover, nestin expression was also observed in the white matter of ventral spinal cord, extending into arborizing processes centripetally from the pial surface toward the central canal. At 4 weeks after injury, nestin expression in ependyma decreased 10 mm from the injury site. But nestin expression in white matter increased dramatically with a 100-fold increase in nestin originating from the pial surface, and extension now to all the white matter. The latter was accompanied by glial fibrillary acidic protein positivity into very long arborizing processes, morphologically compatible with radial glia. The findings suggest two possible sources of precursor cells in adult mammalian spinal cord; ependyma of the central canal and subpial astrocytes. Subpial astrocytes may be associated with neural repair and regeneration after spinal cord injury.

Early scheduled laparoscopic cholecystectomy following percutaneous transhepatic gallbladder drainage for patients with acute cholecystitis.

AIM: The present study was conducted to evaluate the effectiveness of early scheduled laparoscopic cholecystectomy (LC) following percutaneous transhepatic gallbladder drainage (PTGBD) for patients with acute cholecystitis. PATIENTS AND METHODS: 31 patients with acute cholecystitis were treated by early scheduled LC following PTGBD (group 1). These patients were compared with 9 patients treated by early LC without PTGBD (group 2) and with 12 patients treated by delayed LC following conservative therapy (group 3) for the success rate of intraoperative cholangiography, the conversion rate to open cholecystectomy, operative time, and hospital stay. Early scheduled LC following PTGBD was defined as scheduled LC when the patient's condition recovered and it was performed 1-7 days (mean: 4 days) after admission. The patients' age in group 1, 2, and 3 was 66 +/- 13, 65 +/- 10, and 64 +/- 9 years, respectively, without significant difference. Most of the patients had additional diseases. RESULTS: The success rate of intraoperative cholangiography was 97% (30/31) in group 1, 67% (6/9) in group 2, and 67% (8/12) in group 3. The conversion rate to open cholecystectomy was 3% (1/31) in group 1, 33% (3/9) in group 2, and 33% (4/12) in group 3. The operative time for LC was 89 +/- 33 min in group 1, 116 +/- 24 min in group 2, and 135 +/- 30 min in group 3. The mean hospital stay after LC was 9 +/- 4 days in group 1, 9 +/- 3 days in group 2, and 17 +/- 7 days in group 3. In group 1, the success rate of intraoperative cholangiography was higher, the conversion rate to open cholecystectomy was lower, and operative time was shorter than in groups 2 and 3 with significant difference (p <0.05, p <0.05, and p <0.01, respectively). CONCLUSION: The findings of this study indicate that early scheduled LC following PTGBD is a safe and effective therapeutic option for patients with acute cholecystitis especially in elderly and complicated patients.

Localization of sarcoglycan, neuronal nitric oxide synthase, beta-dystroglycan, and dystrophin molecules in normal skeletal myofiber: triple immunogold labeling electron microscopy.

In order to investigate the mode of existence of the sarcoglycan complex, neuronal nitric oxide synthase (nNOS), beta-dystroglycan, and dystrophin in the normal skeletal myofiber, we examined the ultrastructural localization and mutual spatial relationship of nNOS, beta-dystroglycan, dystrophin, and the individual components of the sarcoglycan complex by using triple immunogold labeling electron microscopy. Each molecule of alpha-, beta-, gamma- and delta-sarcoglycans is located intracellularly or extracellularly near the muscle plasma membrane mostly in accordance with the sarcoglycan antigenic sites against which the antibodies were generated. The association of different two and/or three sarcoglycan molecules out of alpha-, beta-, gamma- and delta-sarcoglycan molecules was frequently observed. Each molecule of nNOS, beta-dystroglycan, and dystrophin was ultrastructurally noted along the cell surface of normal skeletal myofibers. Moreover, the close relation of a sarcoglycan molecule with beta-dystroglycan and dystrophin, and the association of nNOS with dystrophin were also confirmed ultrastructurally. Thus, this study demonstrated that the constituting molecules of the sarcoglycan complex, nNOS, beta-dystroglycan, and dystrophin existed in the form of a cluster at the normal muscle plasma membrane. The association of nNOS with dystrophin and its associated glycoproteins may form a macromolecular signaling complex at the muscle plasma membrane.

Angiotensin subtype-2 receptor (AT2 ) negatively regulates subtype-1 receptor (AT1 ) in signal transduction pathways in cultured porcine adrenal medullary chromaffin cells.

BACKGROUND: Two distinct types of angiotensin II (AngII) receptors, AT1 and AT2, have been cloned. We have shown previously that stimulation of AT2 reduces intracellular cyclic guanosine monophosphate (cGMP) levels in cultured porcine chromaffin cells in which AT2 is the predominantly expressed receptor. However, it has not been determined whether AT1 or AT2 affects signal transduction pathways involving mitogen-activated protein kinases (MAPKs) and signal transducers and activators of transcription (STATs) in chromaffin cells. Also, it is unclear whether cGMP/protein kinase G (PKG) is involved in the regulation of MAPKs and STATs in these cells. DESIGN: Chromaffin cells were derived from porcine adrenal medulla. The effects of AngII alone (representing physiological conditions), AngII plus CV-11974 (an AT1 antagonist, which simulates specific AT2 stimulation), AngII plus PD 123319 (an AT2 antagonist, which simulates specific AT1 stimulation), and 8-Br-cGMP (a membrane-permeable cGMP analogue) alone on MAPKs (ERKs, JNK, p-38 MAPK) and STATs (STATs 1, 3 and 5) activity were measured. METHODS: Phosphorylated MAPKs (extracellular signal-related kinases (ERKs), c-jun N-terminal kinase (JNK) and p38 MAPK) and STATs (STATs 1, 3 and 5) were measured by immunoprecipitation-Western blot analysis (IP-Western blot). RESULTS: AT1 stimulation markedly increased expression of ERKs, JNK, p38 MAPK via Ca2+-dependent protein kinase C (PKC) isoforms (cPKC), as well as STATs 1, 3 and 5 in cultured porcine chromaffin cells. In contrast, AT2 stimulation markedly decreased the expression of these signaling molecules. Also, 8-Br-cGMP alone induced increases in ERKs, JNK, p38 MAPK, and STATs 1, 3 and 5. Because AT2 inhibits cGMP production, we speculate that AT2 may act to suppress cGMP production, which in turn reduces the activity of both MAPKs and STATs in chromaffin cells. CONCLUSION: AT2 negatively regulates AT1 in signal transduction pathways in chromaffin cells.

Leptin stimulates catecholamine synthesis in a PKC-dependent manner in cultured porcine adrenal medullary chromaffin cells.

We have previously shown that murine recombinant leptin directly stimulates catecholamine synthesis through the long form of the leptin receptor (Ob-Rb) expressed in cultured porcine chromaffin cells. Additionally, we found that leptin activates IP3 production after PLC activation. It is well established that activation of PLC elicits IP3 production as well as an increase in diacylglycerol, a compound that stimulates PKC. Therefore, we investigated the involvement of PKC in leptin-induced catecholamine synthesis. Leptin was found to induce significant increases in PKC activity in a dose-dependent manner (1, 10, and 100 nM); chelation of extracellular Ca(2+) by EDTA abolished this PKC stimulatory activity. We also confirmed by Western blot analysis that leptin (at 100 nM) induced significant increases in Ca(2+)-dependent PKC alpha, -beta(I), and -gamma expression. The activity of the rate-limiting enzyme tyrosine hydroxylase (TH) in the biosynthesis of catecholamine is regulated at the transcriptional and posttranscriptional levels. TH enzyme activity and TH mRNA levels induced by 100 nM leptin were significantly inhibited by the PKC inhibitor Ro 32-0432 as well as by EDTA. In addition, increases in TH protein and intracellular catecholamine content stimulated by leptin were completely inhibited by Ro 32-0432. Leptin markedly activated ERKs and, to a lesser extent, JNK; these stimulatory effects on ERKs and JNK were completely inhibited by Ro 32-0432 as well as EDTA. In contrast, leptin did not activate P38 MAPK. Similar to leptin, PMA activated ERK and JNK. Nicardipine and omega-conotoxin GVIA, each at 1 microM, were effective at inhibiting leptin-induced TH enzyme activity, TH mRNA accumulation, PKC activity, and ERK activity. Leptin increased activating protein-1 DNA-binding activity, and this was diminished by Ro 32-0432 as well as EDTA, similar to the reduction of TH mRNA levels. In addition, using supershift analysis, we documented the involvement of c-Fos and, to a lesser extent, c-Jun in leptin-induced activating protein-1 activity. These results indicate that leptin stimulates Ca(2+)-dependent PKC isoform-dependent catecholamine synthesis in porcine chromaffin cells. Previously, we had shown that leptin stimulated cAMP. The present study also showed that H89 (a PKA inhibitor) moderately, but significantly, inhibited leptin-induced ERK and TH mRNA. Consistent with this finding, leptin is shown here to activate novel PKC epsilon, which is assumed to stimulate Raf, upstream of ERKs, via cAMP, supporting the suggestion that Ca(2+)-independent novel PKC may also play some physiological role in regulating catecholamine synthesis.