Mood alterations, anxiety, and cognitive impairments associated with adult-onset hypothyroidism often persist despite replacement treatment. In rodent models of hypothyroidism, replacement does not ...bring 3-iodothyronamine (Tsub.1AM) brain levels back to normal. Tsub.1AM is a thyroid hormone derivative with cognitive effects. Using a pharmacological hypothyroid mouse model, we investigated whether augmenting levothyroxine (L-Tsub.4) with Tsub.1AM improves behavioural correlates of depression, anxiety, and memory and has an effect on hippocampal neurogenesis. Hypothyroid mice showed impaired performance in the novel object recognition test as compared to euthyroid mice (discrimination index (DI): 0.02 ± 0.09 vs. 0.29 ± 0.06; t = 2.515, p = 0.02). L-Tsub.4 and L-Tsub.4+Tsub.1AM rescued memory (DI: 0.27 ± 0.08 and 0.34 ± 0.08, respectively), while Tsub.1AM had no effect (DI: −0.01 ± 0.10). Hypothyroidism reduced the number of neuroprogenitors in hippocampal neurogenic niches by 20%. L-Tsub.4 rescued the number of neuroprogenitors (mean diff = 106.9 ± 21.40, t = 4.99, psub.corr = 0.003), while L-Tsub.4+Tsub.1AM produced a 30.61% rebound relative to euthyroid state (mean diff = 141.6 ± 31.91, t = 4.44, psub.corr = 0.004). We performed qPCR analysis of 88 genes involved in neurotrophic signalling pathways and found an effect of treatment on the expression of Ngf, Kdr, Kit, L1cam, Ntf3, Mapk3, and Neurog2. Our data confirm that L-Tsub.4 is necessary and sufficient for recovering memory and hippocampal neurogenesis deficits associated with hypothyroidism, while we found no evidence to support the role of non-canonical TH signalling.
Parkinson's disease (PD) is frequently associated with gastrointestinal (GI) symptoms, including constipation and defecatory dysfunctions. The mechanisms underlying such disorders are still largely ...unknown, although the occurrence of a bowel inflammatory condition has been hypothesized. This study examined the impact of central dopaminergic degeneration, induced by intranigral injection of 6-hydroxydopamine (6-OHDA), on distal colonic excitatory tachykininergic motility in rats.
Animals were euthanized 4 and 8 weeks after 6-OHDA injection. Tachykininergic contractions, elicited by electrical stimulation or exogenous substance P (SP), were recorded in vitro from longitudinal muscle colonic preparations. SP, tachykininergic NK1 receptor, and glial fibrillary acidic protein (GFAP) expression, as well as the density of eosinophils and mast cells in the colonic wall, were examined by immunohistochemical analysis. Malondialdehyde (MDA, colorimetric assay), TNF, and IL-1β (ELISA assay) levels were also examined. The polarization of peritoneal macrophages was evaluated by real-time PCR.
In colonic preparations, electrically and SP-evoked tachykininergic contractions were increased in 6-OHDA rats. Immunohistochemistry displayed an increase in SP and GFAP levels in the myenteric plexus, as well as NK1 receptor expression in the colonic muscle layer of 6-OHDA rats. MDA, TNF, and IL-1β levels were increased also in colonic tissues from 6-OHDA rats. In 6-OHDA rats, the number of eosinophils and mast cells was increased as compared with control animals, and peritoneal macrophages polarized towards a pro-inflammatory phenotype.
The results indicate that the induction of central nigrostriatal dopaminergic degeneration is followed by bowel inflammation associated with increased oxidative stress, increase in pro-inflammatory cytokine levels, activation of enteric glia and inflammatory cells, and enhancement of colonic excitatory tachykininergic motility.
Gut fibrosis occurs under chronic inflammation. This study examined the effects of different cyclooxygenase (COX) inhibitors on fibrosis in the inflamed colon.
Colitis was induced by ...2,4-dinitrobenzenesulfonic acid (DNBS) in albino male Sprague-Dawley rats. After 6, 12 and 18 days, macroscopic and microscopic damage, collagen and elastic fibre content were examined. At day 6, pro-fibrotic factors (collagen I and III, hydroxyproline, fibronectin, matrix metalloproteinase-2 and -9), transforming growth factor-beta (TGF-β) signalling TGF-β, Ras homolog gene family member A (RhoA), phosphorylated small mother against decapentaplegic (pSMAD)-2 and -6 and peristalsis were assessed, and the effects of indomethacin, SC-560 or celecoxib were tested.
Six days after DNBS administration, significant histopathological signs of fibrotic remodelling were observed in rats. At day 6, pro-fibrotic factors were up-regulated and colonic peristalsis was altered. COX inhibitors reversed the histochemical, molecular and functional changes in the fibrotic colon. COX inhibition reduced TGF-β expression, SMAD2 phosphorylation and RhoA, and increased SMAD6 expression.
Colonic fibrosis is associated with altered bowel motility and induction of profibrotic factors driven by TGF-β signalling. COX-1 and COX-2 inhibition counteracts this fibrotic remodelling by the modulation of TGF-β/SMAD signalling, mainly via SMAD6 induction and reduction in SMAD2 phosphorylation.
•Rotenone induces RhoA-activation in mesencephalic cell cultures.•Rotenone upregulates α-syn and connexin 43 expression in DA neurons.•Rotenone decreases 3HDA uptake and neurite length in DA ...neurons.•RhoA inhibitors, C3 and simvastatin, revert rotenone effects in DA neurons.
Mesencephalic cell cultures are a good model to study the vulnerability of dopaminergic neurons and reproduce, in vitro, experimental models of Parkinson’s disease. Rotenone associated as an environmental neurotoxin related to PD, is able to provoke dopaminergic neuron degeneration by inhibiting complex I of the mitochondrial respiratory chain and by inducing accumulation of α-synuclein. Recently, rotenone has been described to activate RhoA, a GTPase protein.
In the present study we evaluated a possible neuroprotective effect of Rho-inhibitor molecules on rotenone-damaged dopaminergic (DA) neurons obtained from mouse primary mesencephalic cell culture.
Our results showed that Clostridium Botulinum C3 toxin (C3) and simvastatin, as RhoA inhibitors, were able to protect DA neurons from rotenone damages. In fact, pretreatment with C3 or simvastatin significantly prevented the reduction of 3Hdopamine uptake, neurites injury and the expression patterns of proteins like α-syn, actin and connexin 43.
Despite increasing evidence indicates polyamines as a convergence point for signaling pathways, including cell growth and differentiation, a unifying concept to interpret their role is still missing. ...The activity of ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine biosynthesis, is tightly regulated by a complex molecular machinery, and the demonstration of the existence of multiple ODC paralogs, lacking decarboxylation activity, suggests additional layers of complexity to the intricate ODC regulatory pathway. Because of their extraordinary regenerative abilities and abundance of stem cells, planarians have potential to contribute to our understanding of polyamine function in an in vivo context. We undertook a study on ODC function in planarians and we found six planarian ODCs (ODC1-6). Five out of six ODC homologs carry substitutions of key aminoacids for enzymatic activity, which makes them theoretically unable to decarboxylate ornithine. Silencing of ODC5 and 6 produced a complex phenotype, by prompting animals to an aberrant response, following chronic injury without tissue removal. Phenotype is neither rescued by putrescine, nor mimicked by difluoromethylornithine treatment. Moreover, the co-silencing of other genes of the ODC regulatory pathway did not modulate phenotype outcome or severity, thus suggesting that the function/s of these ODC-like proteins might be unrelated to decarboxylase activity and putrescine production.
Abstract
Background and purpose
Changes in gut microbiota composition, enteric inflammation, impairments of the intestinal epithelial barrier and neuroplastic changes in the enteric nervous ...system have been reported in Parkinson's disease (PD) patients and could contribute to the onset of both neurological and gastrointestinal symptoms. However, their mutual interplay has rarely been investigated. This study evaluated, in an integrated manner, changes in faecal microbiota composition, morphofunctional alterations of colonic mucosal barrier and changes of inflammatory markers in blood and stools of PD patients.
Methods
Nineteen PD patients and nineteen asymptomatic subjects were enrolled. Blood lipopolysaccharide binding protein (LBP, marker of altered intestinal permeability) and interleukin‐1β (IL‐1β) levels, as well as stool IL‐1β and tumour necrosis factor (TNF) levels, were evaluated. Gut microbiota analysis was performed. Epithelial mucins, collagen fibres, claudin‐1 and S100‐positive glial cells as markers of an impairment of the intestinal barrier, mucosal remodelling and enteric glial activation were evaluated on colonic mucosal specimens collected during colonoscopy.
Results
Faecal microbiota analysis revealed a significant difference in the α‐diversity in PD patients compared to controls, while no differences were found in the β‐diversity. Compared to controls, PD patients showed significant chenags in plasma LBP levels, as well as faecal TNF and IL‐1β levels. The histological analysis showed a decrease in epithelial neutral mucins and claudin‐1 expression and an increased expression of acidic mucins, collagen fibres and S100‐positive glial cells.
Conclusions
Parkinson's disease patients are characterized by enteric inflammation and increased intestinal epithelial barrier permeability, as well as colonic mucosal barrier remodelling, associated with changes in gut microbiota composition.
The murine model of high fat diet (HFD)-induced obesity is characterized by an increment of intestinal permeability, secondary to an impairment of mucosal epithelial barrier and enteric inflammation, ...followed by morphofunctional rearrangement of the enteric nervous system. The present study investigated the involvement of abdominal macrophages in the mechanisms underlying the development of enteric dysmotility associated with obesity.
Wild type C57BL/6J mice were fed with HFD (60% kcal from fat) or normocaloric diet (NCD, 18% kcal from fat) for 8 weeks. Groups of mice fed with NCD or HFD were treated with clodronate encapsulated into liposomes to deplete abdominal macrophages. Tachykininergic contractions, elicited by electrical stimulation or exogenous substance P (SP), were recorded in vitro from longitudinal muscle colonic preparations. Substance P distribution was examined by confocal immunohistochemistry. The density of macrophages in the colonic wall was examined by immunohistochemical analysis. Malondialdehyde (MDA, colorimetric assay) and IL-1β (ELISA assay) levels were also evaluated.
MDA and IL-1β levels were increased in colonic tissues from HFD-treated animals. In colonic preparations, electrically evoked tachykininergic contractions were enhanced in HFD mice. Immunohistochemistry displayed an increase in substance P immunoreactivity in myenteric ganglia, as well as in the muscular layers of colonic cryosections from obese mice. Macrophage depletion in HFD mice was associated with a significant reduction of colonic inflammation. In addition, the decrease in macrophage density attenuated the morphofunctional alterations of tachykininergic pathways observed in obese mice.
Obesity elicited by HFD determines a condition of colonic inflammation, followed by a marked rearrangement of motor excitatory tachykininergic enteric nerves. Macrophage depletion counteracted the morphofunctional changes of colonic neuromuscular compartment, suggesting a critical role for these immune cells in the onset of enteric dysmotility associated with obesity.
Parkinson's disease is frequently associated with gastrointestinal symptoms, mostly represented by constipation and defecatory dysfunctions. This study examined the impact of central dopaminergic ...denervation, induced by injection of 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle, on distal colonic excitatory cholinergic neuromotor activity in rats. Animals were euthanized 4 and 8 weeks after 6-OHDA injection. In vivo colonic transit was evaluated by radiologic assay. Electrically induced and carbachol-induced cholinergic contractions were recorded in vitro from longitudinal and circular muscle colonic preparations, whereas acetylcholine levels were assayed in the incubation media. Choline acetyltransferase (ChAT), HuC/D (pan-neuronal marker), muscarinic M2 and M3 receptors were assessed by immunohistochemistry or western blot assay. As compared with control rats, at week 4, 6-OHDA-treated animals displayed the following changes: decreased in vivo colonic transit rate, impaired electrically evoked neurogenic cholinergic contractions, enhanced carbachol-induced contractions, decreased basal and electrically stimulated acetylcholine release from colonic tissues, decreased ChAT immunopositivity in the neuromuscular layer, unchanged density of HuC/D immunoreactive myenteric neurons, and increased expression of colonic muscarinic M2 and M3 receptors. The majority of such alterations were also detected at week 8 post 6-OHDA injection. These findings indicate that central nigrostriatal dopaminergic denervation is associated with an impaired excitatory neurotransmission characterized by a loss of myenteric neuronal ChAT positivity and decrease in acetylcholine release, resulting in a dysregulated smooth muscle motor activity, which likely contributes to the concomitant decrease in colonic transit rate.
The performances of 9 accessions of Cipolla di Giarratana landrace were evaluated at 5 different sites located 2 in the area where this landrace is traditionally grown (South-Eastern Sicily, 550 m ...asl), 2 in the neighbor areas with similar average altitude, and one on the South East coast of Sicily (sea level). Biometric and morphological traits, flavonol content and sensory profile were all considered in the valorisation of a typical product of a marginal area of Sicily. Data on the actual yield and crop management at farm scale were also obtained involving more than half of the growers actually cultivating Cipolla di Giarratana, and measuring yield, plant density, and bulb weight directly on the farms. The Cipolla di Giarratana landrace is characterised by a large and heavy bulb (535 g), strongly flattened at the poles, with the maximum diameter at the central section, and white in colour. Significant differences in bulb weight and diameter were found among accessions and locations, but there were no interactions between them and one accession reported the highest bulb weight value in all of the locations studied. With regards to bulb weight, farm scale data confirm the results we obtained at the experimental locations. Fifty percent of registered yield at farm scale ranged between 86 and 152 t ha–1 with a median of 119 t ha–1, and measured plant density revealed that 50% of the farmers planted 20-27 plants per square meter. Analysis of the UV-vis and mass spectra showed the presence of 10 different flavonols with Quercetin as the most represented flavonol. The sensory profile of Cipolla di Giarratana onion showed that this landrace is characterised by a high intensity of sweet, typical fresh flavour and texture perception.
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