After the detection of bovine spongiform encephalopathy (BSE), and a zoonotic transmissible spongiform encephalopathy (TSE) caused by the pathological prion protein (PrPSc) in two goats, the investigation of goat prions became of greater interest. Therefore, a broad collection of European goat TSE isolates, including atypical scrapie, CH1641 and goat BSE as reference prion strains were biochemically characterised and subsequently inoculated into seven rodent models for further analysis (already published results of this comprehensive study are reviewed here for comparative reasons). We report here the histopathological and immunohistochemical data of this goat TSE panel, obtained after the first passage in Tgshp IX (tg-shARQ) mice, which overexpress the ovine prion protein. In addition to the clear-cut discrimination of all reference prion strains from the classical scrapie (CS) isolates, we were further able to determine three categories of CS strains. The investigation further indicates the occurrence of sub-strains that slightly resemble distant TSE strains, such as BSE or CH1641, reinforcing the theory that CS is not a single strain but a mixture of sub-strains, existing at varying extents in one isolate. This study further proved that Tgshp IX is a potent and reliable tool for the in-depth characterisation of prion strains.

We previously reported that a pathogenic abnormality in the barrier and water-holding functions of the stratum corneum (SC) in the skin of patients with atopic dermatitis (AD) is mainly attributable to significantly decreased levels of total ceramides in the SC. That decrease is mediated by the abnormal expression of a novel ceramide-reducing enzyme, sphingomyelin/glucosylceramide deacylase (SGDase), which is the β-subunit (ASAH1b) of acid ceramidase. In this study, we determined whether mice overexpressing ASAH1b in their epidermis develop AD-like skin symptoms. We generated transgenic (TG) mice overexpressing ASAH1b, regulated by the involucrin promoter, to localize its expression in the upper epidermis. After hair removal using a depilatory cream containing glycolic acid, the TG mice without any visible skin inflammation at 8 weeks of age had increased levels of ASAH1b and decreased levels of SC ceramide, with disrupted barrier functions measured by trans-epidermal water loss compared to the wild-type (WT) mice. Interestingly, enzymatic assays revealed that SGDase activity was not detectable in the skin of the TG mice compared to WT mice. Immunological staining revealed that there was an increased expression level of IL-33 in the epidermis and an accumulation of macrophages in the dermis of TG mice compared to WT mice, which are phenotypic characteristics of AD, that were exacerbated by tape-stripping of the skin. In the skin of the TG mice, the mRNA levels of IL-5, CCL11, IL-22, CXCL10, and IFNγ were significantly upregulated compared to the WT mice, and tape-stripping significantly increased the mRNA levels of IL-4, IL-33, CXCL1, CXCL12, TLR9, and CD163 compared to WT mice. These findings strongly indicate that the skin of the depilatory cream-treated TG mice exists in an atopic dry skin condition that is highly sensitive to various environmental stimuli. The sum of our results suggests that ASAH1b itself, even in the absence of its enzymatic activity, is a major etiologic factor for atopic dry skin symptoms via an unknown mechanism.

Brain glucose hypometabolism and insulin alterations are common features of many neurological diseases. Herein we sought to corroborate the brain glucose hypometabolism that develops with ageing in 12-months old Tau-VLW transgenic mice, a model of tauopathy, as well as to determine whether this model showed signs of altered peripheral glucose metabolism. Our results demonstrated that 12-old months Tau mice exhibited brain glucose hypometabolism as well as basal hyperglycemia, impaired glucose tolerance, hyperinsulinemia, and signs of insulin resistance. Then, we further studied the effect of chronic metformin treatment (9 months) in Tau-VLW mice from 9 to 18 months of age. Longitudinal PET neuroimaging studies revealed that chronic metformin altered the temporal profile in the progression of brain glucose hypometabolism associated with ageing. Besides, metformin altered the content and/or phosphorylation of key components of the insulin signal transduction pathway in the frontal cortex leading to significant changes in the content of the active forms. Thus, metformin increased the expression of pAKT-Y474 while reducing pmTOR-S2448 and pGSK3β. These changes might be related, at least partially, to a slow progression of ageing, neurological damage, and cognitive decline. Metformin also improved the peripheral glucose tolerance and the ability of the Tau-VLW mice to maintain their body weight through ageing. Altogether our study shows that the tau-VLW mice could be a useful model to study the potential interrelationship between tauopathy and central and peripheral glucose metabolism alterations. More importantly our results suggest that chronic metformin treatment may have direct beneficial central effects by post-transcriptional modulation of key components of the insulin signal transduction pathway.

Ebola disease is a lethal viral hemorrhagic fever caused by ebolaviruses within the Filoviridae family with mortality rates of up to 90%. Monoclonal antibody (mAb) based therapies have shown great potential for the treatment of EVD. However, the potential emerging ebolavirus isolates and the negative effect of decoy protein on the therapeutic efficacy of antibodies highlight the necessity of developing novel antibodies to counter the threat of Ebola. Here, 11 fully human mAbs were isolated from transgenic mice immunized with GP protein and recombinant vesicular stomatitis virus-bearing GP (rVSV-EBOV GP). These mAbs were divided into five groups according to their germline genes and exhibited differential binding activities and neutralization capabilities. In particular, mAbs 8G6, 2A4, and 5H4 were cross-reactive and bound at least three ebolavirus glycoproteins. mAb 4C1 not only exhibited neutralizing activity but no cross-reaction with sGP. mAb 7D8 exhibited the strongest neutralizing capacity. Further analysis on the critical residues for the bindings of 4C1 and 8G6 to GPs was conducted using antibodies complementarity-determining regions (CDRs) alanine scanning. It has been shown that light chain CDR3 played a crucial role in binding and neutralization and that any mutation in CDRs could not improve the binding of 4C1 to sGP. Importantly, mAbs 7D8, 8G6, and 4C1 provided complete protections against EBOV infection in a hamster lethal challenge model when administered 12 h post-infection. These results support mAbs 7D8, 8G6, and 4C1 as potent antibody candidates for further investigations and pave the way for further developments of therapies and vaccines.

UNASSIGNED: Chronic intestinal pseudo-obstruction (CIPO) is a type of intestinal dysfunction with symptoms of intestinal blockage but without the actual mechanical obstruction. Currently, there are no drugs available to treat this disease. Herein, we report the characterization of the PrP-SCA7-92Q transgenic (Tg) line as a valuable CIPO mouse model and investigated the tolerability and efficacy of the 5-hydroxytryptamine type-4 receptor (5HT4R) agonist velusetrag as a promising pharmacological treatment for CIPO.
UNASSIGNED: To test the pharmacodynamics of velusetrag, 8-week-old SCA7 Tg mice, which express human mutated Ataxin-7 gene containing 92 CAG repeats under the mouse prion protein promoter, were treated for 5 weeks by oral route with velusetrag at 1 and 3 mg/kg doses or vehicle. Body weight was monitored throughout the treatment. After sacrifice, the small intestine and proximal colon were collected for whole-mount immunostaining. Untreated, age-matched, C57BL/6J mice were also used as controls in comparison with the other experimental groups.
UNASSIGNED: Analysis of SCA7 Tg mice showed tissue damage and alterations, mucosal abnormalities, and ulcers in the distal small intestine and proximal colon. Morphological changes were associated with significant neuronal loss, as shown by decreased staining of pan-neuronal markers, and with accumulation of ataxin-7-positive inclusions in cholinergic neurons. Administration of velusetrag reversed intestinal abnormalities, by normalizing tissue damage and re-establishing the normal level of glia/neuron\'s count in both the small and large intestines.
UNASSIGNED: We demonstrated that the PrP-SCA7-92Q Tg line, a model originally developed to mimic spinocerebellar ataxia, is suitable to study CIPO pathology and can be useful in establishing new therapeutic strategies, such as in the case of velusetrag. Our results suggest that velusetrag is a promising compound to treat patients affected by CIPO or intestinal dysmotility disease.

In rodents, oxytocin (Oxt) contributes to the onset of maternal care by shifting the perception of pups from aversive to attractive. Both Oxt receptor knockout (Oxtr -/-) and forebrain-specific Oxtr knockout (FB/FB) dams abandon their first litters, likely due to a failure of the brain to \'switch\' to a more maternal state. Whether this behavioral shift is neurochemically similar in virgin females, who can display maternal behaviors when repeatedly exposed to pups, or what neuroanatomical substrate is critical for the onset of maternal care remains unknown. To understand similarities and differences in Oxtr signaling in virgin pup-sensitized Oxtr FB/FB as opposed to post-parturient Oxtr -/- and Oxtr FB/FB dams, maternal behavior (pup-sensitized females only) and immediate early gene activation were assessed. Pup-sensitized Oxtr FB/FB females retrieved pups faster on day one of testing and had reduced c-Fos expression in the dorsal lateral septum as compared to virgin pup-sensitized Oxtr +/+ females. This differs from what was observed in post-parturient Oxtr -/- and Oxtr FB/FB dams, where increased c-Fos expression was observed in the nucleus accumbens (NAcc) shell. Based on these data, we then disrupted Oxtr signaling in the NAcc shell or the posterior paraventricular thalamus (pPVT) (control region) of female Oxtr floxed mice using a Cre recombinase expressing adeno-associated virus. Knockout of the Oxtr only in the NAcc shell prevented the onset of maternal care post-parturient females. Our data suggest that a pup-sensitized brain may differ from a post-parturient brain and that Oxtr signaling in the NAcc shell is critical to the onset of maternal behavior.

Lymphatics are involved in the resolution of inflammation and wound healing, but their role in the oral wound healing process after tooth extraction has never been investigated. We therefore sought to evaluate the healing process following the extraction of maxillary molars in two transgenic mouse models: K14-VEGFR3-Ig mice, which lack initial mucosal lymphatic vessels, and K14-VEGFC mice, which have hyperplastic mucosal lymphatics. Maxillary molars were extracted from both transgenic mouse types and their corresponding wild-type (WT) controls. Mucosal and alveolar bone healing were evaluated. A delayed epithelialization and bone regeneration were observed in K14-VEGFR3-Ig mice compared with their WT littermates. The hampered wound closure was accompanied by decreased levels of epidermal growth factor (EGF) and persistent inflammation, characterized by infiltrates of immune cells and elevated levels of pro-inflammatory markers in the wounds. Hyperplastic mucosal lymphatics did not enhance the healing process after tooth extraction in K14-VEGFC mice. The findings indicate that initial mucosal lymphatics play a major role in the initial phase of the oral wound healing process.

Acetylcholine (ACh) neurons in the central nervous system are required for the coordination of neural network activity during higher brain functions, such as attention, learning, and memory, as well as locomotion. Disturbed cholinergic signaling has been described in many neurodevelopmental and neurodegenerative disorders. Furthermore, cotransmission of other signaling molecules, such as glutamate and GABA, with ACh has been associated with essential roles in brain function or disease. However, it is unknown when ACh neurons become cholinergic during development. Thus, understanding the timeline of how the cholinergic system develops and becomes active in the healthy brain is a crucial part of understanding brain development. To study this, we used transgenic mice to selectively label ACh neurons with tdTomato. We imaged serial sectioned brains and generated whole-brain reconstructions at different time points during pre- and postnatal development. We found three crucial time windows-two in the prenatal and one in the postnatal brain-during which most ACh neuron populations become cholinergic in the brain. We also found that cholinergic gene expression is initiated in cortical ACh interneurons, while the cerebral cortex is innervated by cholinergic projection neurons from the basal forebrain. Taken together, we show that ACh neuron populations are present and become cholinergic before postnatal day 12, which is the onset of major sensory processes, such as hearing and vision. We conclude that the birth of ACh neurons and initiation of cholinergic gene expression are temporally separated during development but highly coordinated by brain anatomical structure.

The 5xFAD transgenic mouse model widely used in Alzheimer\'s disease (AD) research recapitulates many AD-related phenotypes with a relatively early onset and aggressive age-dependent progression. Besides developing amyloid peptide deposits alongside neuroinflammation by the age of 2 months, as well as exhibiting neuronal decline by the age of 4 months that intensifies by the age of 9 months, these mice manifest a broad spectrum of behavioural impairments. In this review, we present the extensive repertoire of behavioural dysfunctions in 5xFAD mice, organised into four categories: motor skills, sensory function, learning and memory abilities, and neuropsychiatric-like symptoms. The motor problems, associated with agility and reflex movements, as well as balance and coordination, and skeletal muscle function, typically arise by the time mice reach 9 months of age. The sensory function (such as taste, smell, hearing, and vision) starts to deteriorate when amyloid peptide buildups and neuroinflammation spread into related anatomical structures. The cognitive functions, encompassing learning and memory abilities, such as visual recognition, associative, spatial working, reference learning, and memory show signs of decline from 4 to 6 months of age. Concerning neuropsychiatric-like symptoms, comprising apathy, anxiety and depression, and the willingness for exploratory behaviour, it is believed that motivational changes emerge by approximately 6 months of age. Unfortunately, numerous studies from different laboratories are often contradictory on the conclusions drawn and the identification of onset age, making preclinical studies in rodent models not easily translatable to humans. This variability is likely due to a range of factors associated with animals themselves, housing and husbandry conditions, and experimental settings. In the forthcoming studies, greater clarity in experimental details when conducting behavioural testing in 5xFAD transgenic mice could minimise the inconsistencies and could ensure the reliability and the reproducibility of the results.

Several fungi belonging to the genus Psilocybe, also called \"magic mushrooms\", contain the hallucinogenic drugs psilocybin and psilocin. They are chemically related to serotonin (5-HT). In addition to being abused as drugs, they are now also being discussed or used as a treatment option for depression. Here, we hypothesized that psilocybin and psilocin may act also on cardiac serotonin receptors and studied them in vitro in atrial preparations of our transgenic mouse model with cardiac myocytes-specific overexpression of the human 5-HT4 receptor (5-HT4-TG) as well as in human atrial preparations. Both psilocybin and psilocin enhanced the force of contraction in isolated left atrial preparations from 5-HT4-TG, increased the beating rate in isolated spontaneously beating right atrial preparations from 5-HT4-TG and augmented the force of contraction in the human atrial preparations. The inotropic and chronotropic effects of psilocybin and psilocin at 10 µM were smaller than that of 1 µM 5-HT on the left and right atria from 5-HT4-TG, respectively. Psilocybin and psilocin were inactive in WT. In the human atrial preparations, inhibition of the phosphodiesterase III by cilostamide was necessary to unmask the positive inotropic effects of psilocybin or psilocin. The effects of 10 µM psilocybin and psilocin were abrogated by 10 µM tropisetron or by 1 µM GR125487, a more selective 5-HT4 receptor antagonist. In summary, we demonstrated that psilocin and psilocybin act as agonists on cardiac 5-HT4 receptors.