Space radiation damage rescued by inhibition of key spaceflight associated miRNAs.

Our previous research revealed a key microRNA signature that is associated with spaceflight that can be used as a biomarker and to develop countermeasure treatments to mitigate the damage caused by space radiation. Here, we expand on this work to determine the biological factors rescued by the countermeasure treatment. We performed RNA-sequencing and transcriptomic analysis on 3D microvessel cell cultures exposed to simulated deep space radiation (0.5 Gy of Galactic Cosmic Radiation) with and without the antagonists to three microRNAs: miR-16-5p, miR-125b-5p, and let-7a-5p (i.e., antagomirs). Significant reduction of inflammation and DNA double strand breaks (DSBs) activity and rescue of mitochondria functions are observed after antagomir treatment. Using data from astronaut participants in the NASA Twin Study, Inspiration4, and JAXA missions, we reveal the genes and pathways implicated in the action of these antagomirs are altered in humans. Our findings indicate a countermeasure strategy that can potentially be utilized by astronauts in spaceflight missions to mitigate space radiation damage.

The aryl hydrocarbon receptor pathway plays a central role in the cutaneous response to pollutants

Short- and long-term exposure to atmospheric pollution has significant health effects. The skin is the organ directly in contact with pollutants and is responsible for protection of the organism. Particulate matter (PM) such as polycyclic aromatic hydrocarbons (PAHs) are the basis of certain pulmonary as well as dermatological complications. Pollution exacerbates certain illnesses such as atopic dermatitis and cancer, and it may also participate in delaying wound healing and in the occurrence of chronic ailments such as diabetes. The aryl hydrocarbon receptor (AhR) transcription factor, at the core of these responses to pollutants, is expressed by all cells of the skin. The AhR is subject to tight regulation that depends on its ligand. Pollutants act in a deleterious manner via the AhR, influencing the behaviour of keratinocytes as well as fibroblasts. Natural ligands, on the other hand, allow the noxious effects of pollution to be countered. This non-systematic review of the literature shows that modulation of AhR appears to be an excellent therapeutic approach to improve or stop the cutaneous problems linked to pollution.

Autophagy and Mitophagy-Related Pathways at the Crossroads of Genetic Pathways Involved in Familial Sarcoidosis and Host-Pathogen Interactions Induced by Coronaviruses.

Sarcoidosis is a multisystem disease characterized by the development and accumulation of granulomas, the hallmark of an inflammatory process induced by environmental and/or infectious and or genetic factors. This auto-inflammatory disease mainly affects the lungs, the gateway to environmental aggressions and viral infections. We have shown previously that genetic predisposition to sarcoidosis occurring in familial cases is related to a large spectrum of pathogenic variants with, however, a clustering around mTOR (mammalian Target Of Rapamycin)-related pathways and autophagy regulation. The context of the COVID-19 pandemic led us to evaluate whether such genetic defects may increase the risk of a severe course of SARS-CoV2 infection in patients with sarcoidosis. We extended a whole exome screening to 13 families predisposed to sarcoidosis and crossed the genes sharing mutations with the list of genes involved in the SARS-CoV2 host-pathogen protein-protein interactome. A similar analysis protocol was applied to a series of 100 healthy individuals. Using ENRICH.R, a comprehensive gene set enrichment web server, we identified the functional pathways represented in the set of genes carrying deleterious mutations and confirmed the overrepresentation of autophagy- and mitophagy-related functions in familial cases of sarcoidosis. The same protocol was applied to the set of genes common to sarcoidosis and the SARS-CoV2-host interactome and found a significant enrichment of genes related to mitochondrial factors involved in autophagy, mitophagy, and RIG-I-like (Retinoic Acid Inducible Gene 1) Receptor antiviral response signaling. From these results, we discuss the hypothesis according to which sarcoidosis is a model for studying genetic abnormalities associated with host response to viral infections as a consequence of defects in autophagy and mitophagy processes.

A novel conjunctive microenvironment derived from human subcutaneous adipose tissue contributes to physiology of its superficial layer.

BACKGROUND: In human subcutaneous adipose tissue, the superficial fascia distinguishes superficial and deep microenvironments showing extensions called retinacula cutis. The superficial subcutaneous adipose tissue has been described as hyperplastic and the deep subcutaneous adipose tissue as inflammatory. However, few studies have described stromal-vascular fraction (SVF) content and adipose-derived stromal/stem cells (ASCs) behavior derived from superficial and deep subcutaneous adipose tissue. In this study, we analyzed a third conjunctive microenvironment: the retinacula cutis superficialis derived from superficial subcutaneous adipose tissue. METHODS: The samples of abdominal human subcutaneous adipose tissue were obtained during plastic aesthetic surgery in France (Declaration DC-2008-162) and Brazil (Protocol 145/09). RESULTS: The SVF content was characterized in situ by immunofluorescence and ex vivo by flow cytometry revealing a high content of pre-adipocytes rather in superficial subcutaneous adipose tissue microenvironment. Adipogenic assays revealed higher percentage of lipid accumulation area in ASCs from superficial subcutaneous adipose tissue compared with retinacula cutis superficialis (p < 0.0001) and deep subcutaneous adipose tissue (p < 0.0001). The high adipogenic potential of superficial subcutaneous adipose tissue was corroborated by an up-regulation of adipocyte fatty acid-binding protein (FABP4) compared with retinacula cutis superficialis (p < 0.0001) and deep subcutaneous adipose tissue (p < 0.0001) and of C/EBPα (CCAAT/enhancer-binding protein alpha) compared with retinacula cutis superficialis (p < 0.0001) and deep subcutaneous adipose tissue (p < 0.0001) microenvironments. Curiously, ASCs from retinacula cutis superficialis showed a higher level of adiponectin receptor gene compared with superficial subcutaneous adipose tissue (p = 0.0409), widely known as an anti-inflammatory hormone. Non-induced ASCs from retinacula cutis superficialis showed higher secretion of human vascular endothelial growth factor (VEGF), compared with superficial (p = 0.0485) and deep (p = 0.0112) subcutaneous adipose tissue and with adipogenic-induced ASCs from superficial (p = 0.0175) and deep (p = 0.0328) subcutaneous adipose tissue. Furthermore, ASCs from retinacula cutis superficialis showed higher secretion of Chemokine (C-C motif) ligand 5 (CCL5) compared with non-induced (p = 0.0029) and induced (p = 0.0089) superficial subcutaneous adipose tissue. CONCLUSIONS: This study highlights the contribution to ASCs from retinacula cutis superficialis in their angiogenic property previously described for the whole superficial subcutaneous adipose tissue besides supporting its adipogenic potential for superficial subcutaneous adipose tissue.

Preharvest UV-C treatment affected postharvest senescence and phytochemicals alternation of strawberry fruit with the possible involvement of abscisic acid regulation.

As an environmentally friendly approach for fruit quality improvement, the effect of preharvest UV-C on the physiology of strawberry fruit during postharvest storage remains to be assessed. Strawberry fruit developed with supplementary UV-C were stored at room temperature for 2 weeks. Preharvest UV-C attenuated fruit postharvest senescence and altered phytochemicals composition. Higher ester titer was found in the treated fruit at harvest, whereas higher terpene and furanone contents were detected after 72 h of storage. At harvest, polyphenolics accumulated to a higher level in UV-C group, but the difference disappeared after 24 h of storage. Meanwhile, the intrinsic level of abscisic acid and the expressions of FaPYR1, SnRK2, and FaASR in the UV-C-treated fruit was enhanced at harvest but returned to a lower level as storage proceeded. This study highlights the time-dependent effect of preharvest UV-C on strawberry fruit postharvest biochemical indexes and the possible involvement of abscisic acid signaling factors.

Preharvest Ultraviolet C Treatment Affected Senescence of Stored Strawberry Fruit with a Potential Role of MicroRNAs in the Activation of the Antioxidant System.

Recent studies presented preharvest ultraviolet C (UV-C) as an environmentally friendly approach for the management of horticultural crop diseases. The effect of this approach on quality preservation during postharvest storage has not yet been investigated. Strawberry fruit harvested from plants grown with supplemental UV-C were stored at room temperature for 72 h, and their postharvest shelf-life biochemical indicators were evaluated. The involvement of microRNAs (miRNAs) in the activation of UV-C-induced antioxidant systems was investigated. Preharvest UV-C contributed to the preservation of sugar and organic acid and reduced overall lipid peroxidation in strawberry fruit during storage. We found that miR159 and miR398 were downregulated by preharvest UV-C and that their respective targets were upregulated at the early stage of storage with enhancement of the activity of antioxidant enzymes. The initial burst of H2O2 and O2• - suggested that preharvest UV-C primed the fruit in an antioxidative activated state via reactive-oxygen-species-mediated feedback control with post-transcriptional involvement of miRNAs.

Preharvest Ultraviolet C Irradiation Increased the Level of Polyphenol Accumulation and Flavonoid Pathway Gene Expression in Strawberry Fruit.

Preharvest ultraviolet C (UV-C) irradiation is an innovative approach for increasing the bioactive phytochemical content of strawberries to increase the disease resistance and nutritional value. This study investigated the changes in individual flavonoids in strawberry developed with three different cumulative doses of preharvest UV-C treatment (low, 9.6 kJ m-2; middle, 15 kJ m-2; and high , 29.4 kJ m-2). Significant accumulation (p < 0.05) of phenolics (25-75% increase), namely, cyanidin 3-glucoside, pelargonidin 3-glucoside/rutinoside, glucoside and glucuronide of quercetin and kaempferol, and ellagic acid, was found in the fruit subjected to low and middle supplemental doses of UV-C radiation. The expression of the flavonoid pathway structural genes, i.e., FaCHS1, FaCHI, FaFHT, FaDFR, FaFLS, and FaFGT, was upregulated in the low- and middle-dose groups, while the early stage genes were not affected by the high dose. FaMYB1 was also relatively enhanced in the low- and middle-dose groups, while FaASR was upregulated in only the low-dose group. Hormetic preharvest UV-C dose ranges for enhancing the polyphenol content of strawberries were established for the first time.

Intradermal injection of human adipose-derived stem cells accelerates skin wound healing in nude mice.

BACKGROUND: The use of stem cells from adipose tissue or adipose-derived stem cells (ASCs) in regenerative medicine could be an interesting alternative to bone marrow stem cells because they are easily accessible and available in large quantities. The aim of this study was to evaluate the potential effect of ASCs on the healing of 12 mm diameter-excisional wounds (around 110 mm(2)) in nude mice. METHODS: Thirty nude mice underwent surgery to create one 12-mm excisional wound per mouse (spontaneous healing, n = 6; Cytocare® 532, n = 12; ASCs, n = 12). The Galiano wound model was chosen to avoid shrinkage and thus slow the spontaneous healing (SH) of mouse skin, making it closer to the physiology of human skin healing. Transparent dressings were used to enable daily healing time measurements to be taken. Immunohistochemistry, histological and blood perfusion analysis were carried out on the healed skin. RESULTS: The in vivo results showed the effectiveness of using ASCs on reducing the time needed for complete healing to 21.2 days for SH, 17.4 days for vehicle alone (Cytocare® 532) and 14.6 days with the addition of ASCs (p < 0.001). Moreover, cutaneous perfusion of the healed wound was significantly improved in ASC-treated mice compared to SH group, as shown by laser Doppler flowmetry and the quantitation of blood vessels using immunohistochemistry of αsmooth muscle actin. CONCLUSIONS: The tolerance and efficacy of cryopreserved ASCs to accelerate the complete closure of the wound by increasing the maturation of the skin and its blood perfusion, shows their therapeutic benefit in the wound healing context.

Effects of preharvest ultraviolet-C irradiation on fruit phytochemical profiles and antioxidant capacity in three strawberry (Fragaria × ananassa Duch.) cultivars.

BACKGROUND: Ultraviolet-C (UV-C) has proven effective in extending shelf-life, reducing disease incidence and increasing the levels of health-promoting compounds in several crops. While most studies were conducted at the postharvest stage, our study examined the effect of preharvest UV-C application in three strawberry cultivars (Fragaria × ananassa Duch. 'Albion', 'Charlotte' and 'Seascape'). UV-C treatment was applied from the onset of flowering until the fruits reached commercial maturity on plants grown for two consecutive seasons under greenhouse conditions. The phytochemical profiles and antioxidant capacity of the fruits were assessed at harvest. RESULTS: The ellagic acid and kaempferol-3-glucuronide contents were significantly increased only in fruits of the cultivar 'Albion' collected from UV-C-treated plants in season 1. UV-C did not consistently affect the other phenolic compounds that were measured. Based on the results of the ferric-reducing antioxidant power, oxygen radical absorbance capacity and total phenolic content assays, the antioxidant capacity of the three strawberry cultivars was not affected by UV-C. Season and cultivar had a decisive impact on these parameters. CONCLUSION: The effect of preharvest UV-C on the levels of bioactive compounds in strawberry fruits appears to be cultivar- dependent, with season or growing conditions having a significant impact.

VEGF-A promotes both pro-angiogenic and neurotrophic capacities for nerve recovery after compressive neuropathy in rats.

Nerve recovery following injury is usually incomplete, leaving functional deficits. Our aim was to investigate the neural changes in pro-angiogenic, pro-inflammatory and apoptotic factors during and after chronic nerve compression (CNC). Nerve function was impaired after CNC and was progressively restored after nerve decompression, while nerve blood flow was elevated. While the expression of the pro-inflammatory and pro-angiogenic cytokines IL-6, TNF-α and VEGF-A was high during and after CNC, we observed that inhibition of VEGF-A receptors strongly counteracted the angiogenic response induced by the ex vivo CNC. Activation of the pro-survival transcription factor nuclear factor-kappa B (NF-κB) increased during CNC, returning to control levels after nerve decompression. After nerve decompression, the downregulation of Mdm2 correlated well with an increased expression of pro-apoptotic transcription factor p53. All together, we bring novel evidence that CNC activates transcription factors such as NF-κB and p53, which are key effectors of the cellular stress response, suggesting a neuroprotective process associated with an increased VEGF-A-mediated neurotrophic effect. Our results highlight the role of pro-angiogenic and pro-inflammatory cytokines during CNC that are reinforced by increasing neurotrophic capacity during recovery to promote nerve regeneration.

What can current stimulation tell us about the vascular function of endogenous prostacyclin in healthy rat skin in vivo?

In endothelial function, prostacyclin (PGI(2)) is as important as nitric oxide (NO); however, no test assesses specifically the vascular function of endogenous PGI(2). We hypothesized that PGI(2) has a dominant role in cathodal current-induced vasodilation (CIV) described in human skin. We thus aimed to study, in physiological conditions, the PGI(2) involvement in cathodal CIV in rats in order to use pharmacological blockers that could not be used in humans. CIV was reduced by cyclooxygenase (COX)-1 and PGI(2) synthase (PGIS) and PGI(2) receptor (IP) blockers, but was unchanged by COX-2 and NO synthase (NOS) blockers. The level of 6-ketoPGF(1)(α) present in skin biopsies, measured as endogenous PGI(2), was increased by cathodal current stimulation, except under COX-1 and PGIS inhibition. This study provides evidence that cathodal CIV mainly relies on the release of PGI(2) endogenously produced through the COX-1/PGIS pathway, and then acts on IP receptors to relax the cutaneous microvessels in healthy rats. In contrast, neither COX-2 nor NOS is involved in CIV and the endogenous PGI(2) release by current stimulation. This finding shows that cathodal current stimulation could be a valuable method to assess the vascular function of endogenous PGI(2) in healthy skin.

Carotid endarterectomy impairs blood pressure homeostasis by reducing the physiologic baroreflex reserve.

OBJECTIVE: To assess the impact of carotid endarterectomy on blood pressure homeostasis and baroreflex function, with particular reference to the presence or absence of significant contralateral carotid artery disease, we conducted a prospective study in 80 patients with symptomatic extracranial carotid disease undergoing carotid endarterectomy in a regional teaching hospital over 2 years. METHODS: Patients were divided into two groups: the control group (n = 37) had no significant contralateral carotid disease; patients in the diseased group (n = 23) had either >70% stenosis or occlusion of the contralateral carotid artery. Seventeen patients with abnormal heart rhythms, poor quality recordings, or with intermediate degrees of contralateral carotid stenosis were excluded. Three patients who had previously undergone contralateral carotid endarterectomy were separately evaluated. Atheromatous plaque was removed from carotid lumen and the baroreflex mechanism received direct intraoperative stimulation before and after carotid endarterectomy. The main outcome measures were (1) the hemodynamic response to the carotid endarterectomy, baroreflex sensitivity, and operating set point (the resting blood pressure, which the baroreflex mechanism maintains) before and after removal of the atheromatous plaque, and (2) the responsiveness of the ipsilateral baroreceptor mechanism to direct stimulation. The impact of the presence of contralateral carotid stenosis on these variables was also evaluated. RESULTS: Patients in the two groups were comparable for preoperative demographic, medication, and hemodynamic variables. Carotid endarterectomy led to a rise in mean arterial pressure from 81.3 +/- 3.9 mm Hg to 103.5 +/- 4.6 mm Hg ( P < .00001) and from 87.6 +/- 4.3 mm Hg to 94.0 +/- 4.5 mm Hg ( P < .003) in the diseased and control groups, respectively. The magnitude of blood pressure response was significantly greater in the diseased group than in the control group ( P < .00001). This hypertensive shift was not accompanied by the expected fall in heart rate. Direct baroreflex stimulation prior to carotid endarterectomy caused a significantly greater response in the diseased group, suggesting sensitization of the ipsilateral carotid baroreceptor in the presence of contralateral carotid disease. Furthermore, the baroreflex response was obliterated after endarterectomy. There were significant reductions in baroreflex sensitivity and a hypertensive shift in the operating set point, the magnitude of which was significantly greater in patients with contralateral carotid disease. CONCLUSIONS: Carotid endarterectomy impairs blood pressure homeostasis through surgical destruction of the ipsilateral carotid baroreflex mechanism. Patients with contralateral carotid stenosis have a reduced baroreflex reserve and show greater baroreflex dysfunction and hemodynamic instability after endarterectomy. These patients are at greater risk of postendarterectomy complications and should be monitored closely.

Cellular mechanisms underlying cutaneous pressure-induced vasodilation: in vivo involvement of potassium channels.

In the skin of humans and rodents, local pressure induces localized cutaneous vasodilation, which may be protective against pressure-induced microvascular dysfunction and lesion formation. Once activated by the local pressure application, capsaicin-sensitive nerve fibers release neuropeptides that act on the endothelium to synthesize and release nitric oxide (NO) and prostaglandins, leading to the development of the cutaneous pressure-induced vasodilation (PIV). The present study was undertaken to test in vivo the hypothesis that PIV is mediated or modulated by differential activation of K+ channels in anesthetized rats using pharmacological methods. Local pressure was applied at 11.1 Pa/s. Endothelium-independent and -dependent vasodilation were tested using iontophoretic delivery of sodium nitroprusside (SNP) and acetylcholine (ACh), respectively, and was correlated with PIV response. PIV was reduced after systemic administration of tetraethylammonium (a nonspecific K+ channel blocker), iberiotoxin [a specific large-conductance Ca2+-activated K+ (BKCa) channel blocker], and glibenclamide [a specific ATP-sensitive K+ (KATP) channel blocker], whereas PIV was unchanged by apamin (a specific small-conductance Ca2+-activated K+ channel blocker) and 4-aminopyridine (a specific voltage-sensitive K+ channel blocker). The responses to SNP and ACh were reduced by iberiotoxin but were unchanged by glibenclamide. We conclude that the cellular mechanism of PIV in skin involves BKCa and KATP channels. We suggest that the opening of BKCa and KATP channels contributes to the hyperpolarization of vascular smooth muscle cells to produce PIV development mainly via the NO and prostaglandin pathways, respectively.

Effect of lignocaine injection in carotid sinus on baroreceptor sensitivity during carotid endarterectomy.

OBJECTIVES: This study was undertaken to test the hypothesis that there is a neural basis for baroreceptor deterioration during carotid endarterectomy (CEA), by investigating intraoperative hemodynamic changes induced by intraluminal carotid stretch stimulation, before and after application of local anesthetic to the adventitial layer of the carotid sinus region. METHODS: This was a prospective study of 20 patients undergoing elective CEA. During CEA, before removal of the atheroma, intraluminal stretch simulation of the carotid baroreceptors (rub test) was performed before and after injection of 1% lignocaine into adventitial tissue of the artery in the region of the carotid sinus. Continuous measurements of mean arterial blood pressure (MAP), electrocardiographic r-r intervals (R-R), heart rate, cardiac vagal tone, and carotid sinus baroreflex were recorded to determine alterations in baroreceptor function. RESULTS: Rub test before injection of lignocaine was associated with a decrease in MAP and heart rate and an increase in R-R, cardiac vagal tone, and carotid baroreflex response, indicating a functioning baroreflex. After lignocaine injection and repetition of the rub test, no significant change was seen in MAP, heart rate, R-R, cardiac vagal tone, or carotid baroreflex response, indicating a nonfunctioning baroreflex. Comparing the peak responses to the rub test stimulus before and after lignocaine injection showed significant differences for all variables (P <.05), with carotid baroreflex response and heart rate being highly significant (P <.0005). CONCLUSIONS: The baroreflex response to intraluminal stretch stimulation of the carotid sinus area is operational in patients undergoing CEA, and this response is abolished by infiltration of local anesthetic into the periadventitial tissue around the carotid sinus.

Evidence for the involvement of VPAC1 and VPAC2 receptors in pressure-induced vasodilatation in rodents.

A transient increase in skin blood flow in response to an innocuous local pressure application, defined as pressure-induced vasodilatation (PIV), delays the occurrence of ischaemia, suggesting a protective feature against applied pressure. The PIV response depends on capsaicin-sensitive nerve fibres and calcitonin gene-related peptide (CGRP) has been shown to be involved. In these fibres, CGRP coexists with pituitary adenylate cyclase-activating polypeptide (PACAP). Three distinct receptors mediate the biological effects of PACAP: VPAC1 and VPAC2 receptors binding with the same affinity for PACAP and vasoactive intestinal peptide and PAC1 receptors showing high selectivity for PACAP. Because the receptors are widely expressed in the nervous system and in the skin, we hypothesized that at least one of them is involved in PIV development. To verify this hypothesis, we used [D-p-Cl-Phe(6),Leu(17)]-VIP (nonspecific antagonist of VPAC1/VPAC2 receptors), PG 97-269 (antagonist of VPAC1 receptors), PACAP(6-38) (antagonist of VPAC2/PAC1 receptors) and Max.d.4 (antagonist of PAC1 receptors) in anaesthetized rodents. The blockade of VPAC1/VPAC2, VPAC1 or VPAC2/PAC1 receptors eliminated the PIV response, whereas PAC1 blockade had no effect, demonstrating an involvement of VPAC1/VPAC2 receptors in PIV development. Moreover, endothelium-independent and -dependent vasodilator responses were unchanged by the VPAC1/VPAC2 antagonist. Thus, the absence of a PIV response following VPAC1/VPAC2 blockade cannot be explained by any dysfunction of the vascular smooth muscle or endothelial vasodilator capacity. The involvement of VPAC1/VPAC2 receptors in the development of PIV seems to imply a series relationship in which each receptor type (CGRP, VPAC1, VPAC2) is necessary for the full transmission of the response.

Heart rate variability after prolonged spaceflights.

Astronauts returning from spaceflight often experience post-flight orthostatic intolerance. This study was designed to determine whether cosmonauts with post-flight syncope could be distinguished from those with no post-flight syncope. The autonomic function was determined in a group of ten subjects, with no previous history of syncope, during a stand test before and after a long-term spaceflight (90 to 198 days). Heart rate (HR) and systolic blood pressure (SBP) were measured beat-by-beat, pre- and post-flight and the spontaneous baroreflex sensitivity and HR variability were studied. Individuals were categorized according to their ability to remain standing for 5 min the day after landing. Three of the ten cosmonauts failed to finish the standing test performed the day after landing (nonfinishers). The spontaneous baroreflex slope was reduced in both groups after the spaceflight. The non-finisher group had a lower SBP (P < 0.05) at rest in pre-flight tests than the group that completed the test (finisher group). The non-finisher group also had higher indicators of parasympathetic activity when supine, both pre- and post-flight, but this difference disappeared with standing. At the end of the stand test, SBP and HR were lower in non-finisher cosmonauts than the finishers, while HR did not increase compared to early measurements in the stand test of the finisher group. These results suggest an impairment in autonomic control of HR, which might contribute to the fainting response.