Decreased NO production in endothelial cells exposed to plasma from ME/CFS patients.

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating disease characterized by severe and persistent fatigue. Along with clinical studies showing endothelial dysfunction (ED) in a subset of ME/CFS patients, we have recently reported altered ED-related microRNAs in plasma from affected individuals. Inadequate nitric oxide (NO), mainly produced by the endothelial isoform of nitric oxide synthase (eNOS) in endothelial cells (ECs), is a major cause of ED. In this study, we hypothesized that plasma from that cohort of ME/CFS patients induces eNOS-related ED in vitro. To test this, we cultured human umbilical vein endothelial cells (HUVECs) in the presence of plasma from either ME/CFS patients (ME/CFS-plasma, n = 11) or healthy controls (HC-plasma, n = 12). Then, we measured the NO production in the absence and presence of tyrosine kinase and G protein-coupled receptors agonists (TKRs and GPCRs, respectively), well-known to activate eNOS in ECs. Our data showed that HUVECs incubated with ME/CFS-plasma produced less NO either in the absence or presence of eNOS activators compared to ones in presence of HC-plasma. Also, the NO production elicited by bradykinin, histamine, and acetylcholine (GPCRs agonists) was more affected than the one triggered by insulin (TKR agonist). Finally, inhibitory eNOS phosphorylation at Thr495 was higher in HUVECs treated with ME/CFS-plasma compared to the same treatment with HC-plasma. In conclusion, this study in vitro shows a decreased NO production in HUVECs exposed to plasma from ME/CFS patients, suggesting an unreported role of eNOS in the pathophysiology of this disease.

Schwann cells orchestrate peripheral nerve inflammation through the expression of CSF1, IL-34, and SCF in amyotrophic lateral sclerosis.

Distal axonopathy is a recognized pathological feature of amyotrophic lateral sclerosis (ALS). In the peripheral nerves of ALS patients, motor axon loss elicits a Wallerian-like degeneration characterized by denervated Schwann cells (SCs) together with immune cell infiltration. However, the pathogenic significance of denervated SCs accumulating following impaired axonal growth in ALS remains unclear. Here, we analyze SC phenotypes in sciatic nerves of ALS patients and paralytic SOD1G93A rats, and identify remarkably similar and specific reactive SC phenotypes based on the pattern of S100ß, GFAP, isolectin and/or p75NTR immunoreactivity. Different subsets of reactive SCs expressed colony-stimulating factor-1 (CSF1) and Interleukin-34 (IL-34) and closely interacted with numerous endoneurial CSF-1R-expressing monocyte/macrophages, suggesting a paracrine mechanism of myeloid cell expansion and activation. SCs bearing phagocytic phenotypes as well as endoneurial macrophages expressed stem cell factor (SCF), a trophic factor that attracts and activates mast cells through the c-Kit receptor. Notably, a subpopulation of Ki67+ SCs expressed c-Kit in the sciatic nerves of SOD1G93A rats, suggesting a signaling pathway that fuels SC proliferation in ALS. c-Kit+ mast cells were also abundant in the sciatic nerve from ALS donors but not in controls. Pharmacological inhibition of CSF-1R and c-Kit with masitinib in SOD1G93A rats potently reduced SC reactivity and immune cell infiltration in the sciatic nerve and ventral roots, suggesting a mechanism by which the drug ameliorates peripheral nerve pathology. These findings provide strong evidence for a previously unknown inflammatory mechanism triggered by SCs in ALS peripheral nerves that has broad application in developing novel therapies.

The cannabinoid beta-caryophyllene (BCP) induces neuritogenesis in PC12 cells by a cannabinoid-receptor-independent mechanism.

Beta-caryophyllene (BCP) is a phytocannabinoid whose neuroprotective activity has been mainly associated with selective activation of cannabinoid-type-2 (CB2) receptors, inhibition of microglial activation and decrease of inflammation. Here, we addressed the potential of BCP to induce neuritogenesis in PC12 cells, a model system for primary neuronal cells that express trkA receptors, respond to NGF and do not express CB2 receptors. We demonstrated that BCP increases the survival and activates the NGF-specific receptor trkA in NGF-deprived PC12 cells, without increasing the expression of NGF itself. The neuritogenic effect of BCP in PC12 cells was abolished by k252a, an inhibitor of the NGF-specific receptor trkA. Accordingly, BCP did not induce neuritogenesis in SH-SY5Y neuroblastoma cells, a neuronal model that does not express trkA receptors and do not respond to NGF. Additionally, we demonstrated that BCP increases the expression of axonal-plasticity-associated proteins (GAP-43, synapsin and synaptophysin) in PC12 cells. It is known that these proteins are up-regulated by NGF in neurons and neuron-like cells, such as PC12 cells. Altogether, these findings suggest that BCP activates trka receptors and induces neuritogenesis by a mechanism independent of NGF or cannabinoid receptors. This is the first study to show such effects of BCP and their beneficial role in neurodegenerative processes should be further investigated.

Insulin binding characteristics in canine muscle tissue: effects of the estrous cycle phases / Características de ligação da insulina no tecido muscular canino: efeitos da fase do ciclo estral

Hormonal fluctuations during the different estrous cycle are a well-recognized cause of insulin resistance in bitches, and little is known about insulin receptor binding or post-binding defects associated with insulin resistance in dogs. To evaluate insulin binding characteristics in muscle tissue of bitches during the estrous cycle, 17 owned bitches were used in the study (six in anestrus, five in estrus, and six in diestrus). An intravenous glucose tolerance test (IVGTT) was performed in all patients by means of injection of 1mL/kg of a glucose 50% solution (500mg/kg), with blood sample collection for glucose determination at 0, 3, 5, 7, 15, 30, 45 and 60 minutes after glucose infusion. Muscle samples, taken after spaying surgery, were immediately frozen in liquid nitrogen and then stored at -80 ºC until the membranes were prepared by sequential centrifugation after being homogenized. For binding studies, membranes were incubated in the presence of 20,000cpm of human 125I-insulin and in increasing concentrations of unlabeled human regular insulin for cold saturation. The IVGTT showed no differences among bitches during the estrous cycle regarding baseline glycemia or glycemic response after glucose infusion. Two insulin binding sites - high-affinity and low-affinity ones - were detected by Scatchard analysis, and significant statistical differences were observed in the dissociation constant (Kd1) and maximum binding capacity (Bmax1) of the high-affinity binding sites. The Kd1 for the anestrus group (6.54±2.77nM/mg of protein) was smaller (P<0.001) than for the estrus (28.54±6.94nM/mg of protein) and diestrus (15.56±3.88nM/mg of protein) groups. Bmax1 in the estrus (0.83±0.42nM/mg of protein) and diestrus (1.24±0.24nM/mg of protein) groups were also higher (P<0.001) than the values observed in anestrus (0.35±0.06nM/mg of protein). These results indicate modulation of insulin binding characteristics during different phases of the estrous cycle in dogs, showing that muscle insulin binding affinity for its receptor is reduced during estrus and diestrus. However, this poor hormone-receptor affinity is compensated for by a greater total binding capacity, once there is no difference in patients' glycemic response after an intravenous glucose load.(AU)

As flutuações hormonais durante as diferentes fases do ciclo estral são uma causa importante de resistência insulínica em fêmeas caninas, e poucas informações são conhecidas sobre defeitos na ligação da insulina ao seu receptor, ou defeitos pós-receptor associados com resistência à insulina em cães. Para avaliar as características da ligação insulina-receptor no tecido muscular de cadelas durante o ciclo estral, dezessete pacientes foram utilizadas no estudo (seis em anestro, cinco em estro e seis em diestro). Um teste de tolerância à glicose intravenosa (IVGTT) foi realizado em todas as pacientes por meio da infusão de 1mL/kg de uma solução de glicose 50% (500mg/kg), com coletas de sangue para determinação de glicemia nos tempos 0, 3, 5, 7, 15, 30, 45 e 60 minutos da injeção de glicose. Amostras de tecido muscular foram coletadas durante ovariohisterectomia, imediatamente congeladas em nitrogênio líquido, e posteriormente armazenadas a -80°C até a preparação das membranas por meio de homogeneização e centrifugação sequencial. Para os experimentos de ligação hormônio-receptor, as membranas foram incubadas na presença de 20.000cpm de 125I-insulina humana, e concentrações crescentes de insulina regular humana não marcada para saturação fria. O IVGTT não mostrou diferenças entre as pacientes em diferentes fases do ciclo estral com relação a glicemia basal, ou na resposta glicêmica após infusão de glicose nos tempos estudados. Dois sítios de ligação da insulina, um de alta-afinidade, e outro de baixa afinidade, foram detectados pela análise de Scatchard, e diferenças significativas foram detectadas na constante de dissociação (Kd1) e capacidade de ligação máxima (Bmax1) dos sítios de ligação de alta-afinidade. O Kd1 para o grupo anestro (6,54±2,77nM/mg de proteína) foi menor (P<0,001) que os Kd1 dos grupos estro (28,54±6,94 nM/mg de proteína) e diestro (15,56±3,88nM/mg de proteína). Os Bmax1 dos grupos estro (0,83±0,42nM/mg de proteína) e diestro (1,24±0,24nM/mg de proteína) também foram maiores que os valores encontrados no grupo anestro (0,35±0,06nM/mg de proteína). Estes resultados demonstram uma modulação das características de ligação da insulina nas diferentes fases do ciclo estral em cães, evidenciando uma menor afinidade de ligação da insulina ao seu receptor no tecido muscular durante o estro e diestro. Contudo, esta menor afinidade de ligação hormônio-receptor é compensada por uma maior capacidade de ligação, o que fica também evidenciado pela ausência de diferenças na resposta glicêmica das pacientes após um desafio com glicose por via endovenosa.(AU)

Insulin binding characteristics in canine muscle tissue: effects of the estrous cycle phases / Características de ligação da insulina no tecido muscular canino: efeitos da fase do ciclo estral

Hormonal fluctuations during the different estrous cycle are a well-recognized cause of insulin resistance in bitches, and little is known about insulin receptor binding or post-binding defects associated with insulin resistance in dogs. To evaluate insulin binding characteristics in muscle tissue of bitches during the estrous cycle, 17 owned bitches were used in the study (six in anestrus, five in estrus, and six in diestrus). An intravenous glucose tolerance test (IVGTT) was performed in all patients by means of injection of 1mL/kg of a glucose 50% solution (500mg/kg), with blood sample collection for glucose determination at 0, 3, 5, 7, 15, 30, 45 and 60 minutes after glucose infusion. Muscle samples, taken after spaying surgery, were immediately frozen in liquid nitrogen and then stored at -80 ºC until the membranes were prepared by sequential centrifugation after being homogenized. For binding studies, membranes were incubated in the presence of 20,000cpm of human 125I-insulin and in increasing concentrations of unlabeled human regular insulin for cold saturation. The IVGTT showed no differences among bitches during the estrous cycle regarding baseline glycemia or glycemic response after glucose infusion. Two insulin binding sites - high-affinity and low-affinity ones - were detected by Scatchard analysis, and significant statistical differences were observed in the dissociation constant (Kd1) and maximum binding capacity (Bmax1) of the high-affinity binding sites. The Kd1 for the anestrus group (6.54±2.77nM/mg of protein) was smaller (P<0.001) than for the estrus (28.54±6.94nM/mg of protein) and diestrus (15.56±3.88nM/mg of protein) groups. Bmax1 in the estrus (0.83±0.42nM/mg of protein) and diestrus (1.24±0.24nM/mg of protein) groups were also higher (P<0.001) than the values observed in anestrus (0.35±0.06nM/mg of protein). [...] (AU)

As flutuações hormonais durante as diferentes fases do ciclo estral são uma causa importante de resistência insulínica em fêmeas caninas, e poucas informações são conhecidas sobre defeitos na ligação da insulina ao seu receptor, ou defeitos pós-receptor associados com resistência à insulina em cães. Para avaliar as características da ligação insulina-receptor no tecido muscular de cadelas durante o ciclo estral, dezessete pacientes foram utilizadas no estudo (seis em anestro, cinco em estro e seis em diestro). Um teste de tolerância à glicose intravenosa (IVGTT) foi realizado em todas as pacientes por meio da infusão de 1mL/kg de uma solução de glicose 50% (500mg/kg), com coletas de sangue para determinação de glicemia nos tempos 0, 3, 5, 7, 15, 30, 45 e 60 minutos da injeção de glicose. Amostras de tecido muscular foram coletadas durante ovariohisterectomia, imediatamente congeladas em nitrogênio líquido, e posteriormente armazenadas a -80°C até a preparação das membranas por meio de homogeneização e centrifugação sequencial. Para os experimentos de ligação hormônio-receptor, as membranas foram incubadas na presença de 20.000cpm de 125I-insulina humana, e concentrações crescentes de insulina regular humana não marcada para saturação fria. O IVGTT não mostrou diferenças entre as pacientes em diferentes fases do ciclo estral com relação a glicemia basal, ou na resposta glicêmica após infusão de glicose nos tempos estudados. Dois sítios de ligação da insulina, um de alta-afinidade, e outro de baixa afinidade, foram detectados pela análise de Scatchard, e diferenças significativas foram detectadas na constante de dissociação (Kd1) e capacidade de ligação máxima (Bmax1) dos sítios de ligação de alta-afinidade. O Kd1 para o grupo anestro (6,54±2,77nM/mg de proteína) foi menor (P<0,001) que os Kd1 dos grupos estro (28,54±6,94 nM/mg de proteína) e diestro (15,56±3,88nM/mg de proteína).[...] (AU)

Tyrosine kinase receptor expression in chordomas: phosphorylated AKT correlates inversely with outcome.

Chordomas are rare neoplasms arising from notochord remnants. Tyrosine kinase receptors (RTK) are altered in these lesions. We used a tissue microarray containing 58 chordomas to examine the expression of platelet-derived growth factor receptor (PDGFR)-α and PDGFR-ß, epidermal growth factor receptor (EGFR), c-Met, c-Kit, pAKT, mammalian target of rapamycin, and HER2 by immunohistochemistry and fluorescence in situ hybridization. Most tumors were positive for PDGFR-α (92%), PDGFR-ß (85%), c-Kit (77.4%), c-Met (96%), pAKT (82%), mammalian target of rapamycin (56%), HER2 (24%), and EGFR (26%) by immunohistochemistry. Amplifications or deletions could not be identified for HER2 or EGFR in the 13 cases available for fluorescence in situ hybridization analysis; however, chromosome 7 polysomy was detected in 29% of the cases. The only factor directly associated with a poorer survival rate was pAKT positivity (P = .042). The 5-year survival rate for patients with pAKT-negative chordomas was 100%, whereas it was 45% for patients with pAKT-positive chordomas. Our results confirm that RTKs are frequently altered in chordomas. Given the implications of pAKT positivity, RTK inhibitors might be efficacious, and drugs that inhibit AKT, alone or in combination with radiotherapy, could be an effective treatment for patients with refractory chordomas.