Expression of CD13 and CD26 on extracellular vesicles in canine seminal plasma: preliminary results.

Canine seminal plasma is a complex fluid containing proteins, peptides, enzymes, hormones as well as extracellular vesicles that are involved in many physiological and pathological processes including reproduction. We examined the expression of the extracellular vesicles surface antigens Aminopeptidase-N (CD13) and Dipeptidyl peptidase IV (CD26) by flow cytometry. For this study, third fraction of the ejaculate, from fertile adult male German Shepherd dogs, was manually collected twice, two days apart. FACS analyses revealed that CD13 and CD26 are co-expressed on the 69.3 ± 3.7% of extracellular vesicles and only a 2.0 ± 0.5% of extracellular vesicles express CD26 alone. On the other hand, 28.6 ± 3.6% of seminal EVs express CD13 alone. Our results agree with the hypothesis that CD26 needs to be co-expressed with other signal-transducing molecules, while CD13, can perform functions independently of the presence or co-expression of CD26. The results obtained in normal fertile dogs could represent physiological expression of these enzymes. Therefore, it would be interesting to carry out further studies to evaluate the expression of CD13 and CD26 on extracellular vesicles as biomarker for prostate pathological condition in dogs.

Cardiolipin-mediated temporal response to hydroquinone toxicity in human retinal pigmented epithelial cell line.

Hydroquinone, a potent toxic agent of cigarette smoke, damages retinal pigmented epithelial cells by triggering oxidative stress and mitochondrial dysfunction, two events causally related to the development and progression of retinal diseases. The inner mitochondrial membrane is enriched in cardiolipin, a phospholipid susceptible of oxidative modifications which determine cell-fate decision. Using ARPE-19 cell line as a model of retinal pigmented epithelium, we analyzed the potential involvement of cardiolipin in hydroquinone toxicity. Hydroquinone exposure caused an early concentration-dependent increase in mitochondrial reactive oxygen species, decrease in mitochondrial membrane potential, and rise in the rate of oxygen consumption not accompanied by changes in ATP levels. Despite mitochondrial impairment, cell viability was preserved. Hydroquinone induced cardiolipin translocation to the outer mitochondrial membrane, and an increase in the colocalization of the autophagosome adapter protein LC3 with mitochondria, indicating the induction of protective mitophagy. A prolonged hydroquinone treatment induced pyroptotic cell death by cardiolipin-mediated caspase-1 and gasdermin-D activation. Cardiolipin-specific antioxidants counteracted hydroquinone effects pointing out that cardiolipin can act as a mitochondrial "eat-me signal" or as a pyroptotic cell death trigger. Our results indicate that cardiolipin may act as a timer for the mitophagy to pyroptosis switch and propose cardiolipin-targeting compounds as promising approaches for the treatment of oxidative stress-related retinal diseases.

Liver-directed gene therapy for ornithine aminotransferase deficiency.

Gyrate atrophy of choroid and retina (GACR) is a chorioretinal degeneration caused by pathogenic variants in the gene encoding ornithine aminotransferase (OAT), an enzyme mainly expressed in liver. Affected patients have increased ornithine concentrations in blood and other body fluids and develop progressive constriction of vision fields leading to blindness. Current therapies are unsatisfactory and better treatments are highly needed. In two mouse models of OAT deficiency that recapitulates biochemical and retinal changes of GACR, we investigated the efficacy of an intravenously injected serotype 8 adeno-associated (AAV8) vector expressing OAT under the control of a hepatocyte-specific promoter. Following injections, OAT-deficient mice showed reductions of ornithine concentrations in blood and eye cups compared with control mice injected with a vector expressing green fluorescent protein. AAV-injected mice showed improved electroretinogram response and partial restoration of retinal structure up to one-year post-injection. In summary, hepatic OAT expression by AAV8 vector was effective at correction of hyperornithinemia and improved function and structure of the retina. In conclusion, this study provides proof-of-concept of efficacy of liver-directed AAV-mediated gene therapy of GACR.

Development of l-Dopa-containing diketopiperazines as blood-brain barrier shuttle.

In our overall goal to develop anti-Parkinson drugs, we designed novel diketopiperazines (DKP1-6) aiming to both reach the blood-brain barrier and counteract the oxidative stress related to Parkinson's Disease (PD). The anti-Parkinson properties of DKP 1-6 were evaluated using neurotoxin-treated PC12 cells, as in vitro model of PD, while their cytotoxicity and genotoxicity potentials were investigated in newborn rat cerebral cortex (RCC) and primary human whole blood (PHWB) cell cultures. The response against free radicals was evaluated by the total antioxidant capacity (TAC) assay. Comet assay was used to detect DNA damage while the content of 8-hydroxyl-2'-deoxyguanosine (8-OH-dG) was determined as a marker of oxidative DNA damage. PAMPA-BBB and Caco-2 assays were employed to evaluate the capability of DKP1-6 to cross the membranes. Stability studies were conducted in simulated gastric and intestinal fluids and human plasma. Results showed that DKP5-6 attenuate the MPP + -induced cell death on a nanomolar scale, but a remarkable effect was observed for DKP6 on Nrf2 activation that leads to the expression of genes involved in oxidative stress response thus increasing glutathione biosynthesis and ROS buffering. DKP5-6 resulted in no toxicity for RCC neurons and PHWB cells exposed to 10-500 nM concentrations during 24 h as determined by MTT and LDH assays and TAC levels were not altered in both cultured cell types. No significant difference in the induction of DNA damage was observed for DKP5-6. Both DKPs resulted stable in simulated gastric fluids (t1/2 > 22h). In simulated intestinal fluids, DKP5 underwent immediate hydrolysis while DKP6 showed a half-life higher than 3 h. In human plasma, DKP6 resulted quite stable. DKP6 displayed both high BBB and Caco-2 permeability confirming that the DKP scaffold represents a useful tool to improve the crossing of drugs through the biological membranes.

CRISPR/Cas9-mediated knock-out of AGXT1 in HepG2 cells as a new in vitro model of Primary Hyperoxaluria Type 1.

AGXT1 encodes alanine:glyoxylate aminotransferase 1 (AGT1), a liver peroxisomal pyridoxal 5'-phosphate dependent-enzyme whose deficit causes Primary Hyperoxaluria Type 1 (PH1). PH1 is a rare disease characterized by overproduction of oxalate, first leading to kidney stones formation, and possibly evolving to life-threatening systemic oxalosis. A minority of PH1 patients is responsive to pyridoxine, while the option for non-responders is liver-kidney transplantation. Therefore, huge efforts are currently focused on the identification of new therapies, including the promising approaches based on RNA silencing recently approved. Many PH1-associated mutations are missense and lead to a variety of kinetic and/or folding defects on AGT1. In this context, the availability of a reliable in vitro disease model would be essential to better understand the phenotype of known or newly-identified pathogenic variants as well as to test novel drug candidates. Here, we took advantage of the CRISPR/Cas9 technology to specifically knock-out AGXT1 in HepG2 cells, a hepatoma-derived cell model exhibiting a conserved glyoxylate metabolism. AGXT1-KO HepG2 displayed null AGT1 expression and significantly reduced transaminase activity leading to an enhanced secretion of oxalate upon glycolate challenge. Known pathogenic AGT1 variants expressed in AGXT1-KO HepG2 cells showed alteration in both protein levels and specific transaminase activity, as well as a partial mitochondrial mistargeting when associated with a common polymorphism. Notably, pyridoxine treatment was able to partially rescue activity and localization of clinically-responsive variants. Overall, our data validate AGXT1-KO HepG2 cells as a novel cellular model to investigate PH1 pathophysiology, and as a platform for drug discovery and development.

Extracellular Vesicles and the Inflammasome: An Intricate Network Sustaining Chemoresistance.

Extracellular vesicles (EVs) are membrane enclosed spherical particles devoted to intercellular communication. Cancer-derived EVs (Ca-EVs) are deeply involved in tumor microenvironment remodeling, modifying the inflammatory phenotype of cancerous and non-cancerous residing cells. Inflammation plays a pivotal role in initiation, development, and progression of many types of malignancies. The key feature of cancer-related inflammation is the production of cytokines that incessantly modify of the surrounding environment. Interleukin-1ß (IL-1ß) is one of the most powerful cytokines, influencing all the initiation-to-progression stages of many types of cancers and represents an emerging critical contributor to chemoresistance. IL-1ß production strictly depends on the activation of inflammasome, a cytoplasmic molecular platform sensing exogenous and endogenous danger signals. It has been recently shown that Ca-EVs can activate the inflammasome cascade and IL-1ß production in tumor microenvironment-residing cells. Since inflammasome dysregulation has been established as crucial regulator in inflammation-associated tumorigenesis and chemoresistance, it is conceivable that the use of inflammasome-inhibiting drugs may be employed as adjuvant chemotherapy to counteract chemoresistance. This review focuses on the role of cancer-derived EVs in tuning tumor microenvironment unveiling the intricate network between inflammasome and chemoresistance.

Amniotic fluid stem cell-derived extracellular vesicles are independent metabolic units capable of modulating inflammasome activation in THP-1 cells.

An immunoregulatory role of stem cells, often mediated by their secretome, has been claimed by several studies. Stem cell-derived extracellular vesicles (EVs) are crucial components of the secretome. EVs, a heterogeneous group of membranous vesicles released by many cell types into the extracellular space, are now considered as an additional mechanism for intercellular communication. In this study, we aimed at investigating whether human amniotic stem cell-derived extracellular vesicles (HASC-EVs) were able to interfere with inflammasome activation in the THP-1 cell line. Two subsets of HASC-EVs were collected by sequential centrifugation, namely HASC-P10 and HASC-P100. We demonstrated that HASC-EVs were neither internalized into nor undertake a direct interaction with THP-1 cells. We showed that HASC-P10 and P100 were able to intrinsically produce ATP, which was further converted to adenosine by 5'-nucleotidase (CD73) and ectonucleoside triphosphate diphosphohydrolase-1 (CD39). We found that THP-1 cells conditioned with both types of HASC-EVs failed to activate the NLRP3/caspase-1/inflammasome platform in response to LPS and ATP treatment by a mechanism involving A2a adenosine receptor activation. These results support a role for HASC-EVs as independent metabolic units capable of modifying the cellular functions, leading to anti-inflammatory effects in monocytic cells.

Natriuretic Peptides Regulate Prostate Cells Inflammatory Behavior: Potential Novel Anticancer Agents for Prostate Cancer.

Inflammation, by inducing a tumor-promoting microenvironment, is a hallmark for prostate cancer (PCa) progression. NOD-like receptor protein 3 (NLRP3)-inflammasome activation, interleukin-1ß (IL-1ß) secretion, and cancer cell-released extracellular vesicles (EVs) contribute to the establishment of tumor microenvironment. We have shown that PC3-derived EVs (PC3-EVs) activate inflammasome cascade in non-cancerous PNT2 cells. It is known that the endogenous biomolecules and Natriuretic Peptides (NPs), such as ANP and BNP, inhibit inflammasome activation in immune cells. Here we investigated whether ANP and BNP modify PCa inflammatory phenotype in vitro. By using PNT2, LNCaP, and PC3 cell lines, which model different PCa progression stages, we analyzed inflammasome activation and the related pathways by Western blot and IL-1ß secretion by ELISA. We found that tumor progression is characterized by constitutive inflammasome activation, increased IL-1ß secretion, and reduced endogenous NPs expression. The administration of exogenous ANP and BNP, via p38-MAPK or ERK1/2-MAPK, by inducing NLRP3 phosphorylation, counteract inflammasome activation and IL-1ß maturation in PC3 and PC3-EVs-treated PNT2 cells, respectively. Our results demonstrate that NPs, by interfering with cell-specific signaling pathways, exert pleiotropic anti-inflammatory effects converging toward inflammasome phosphorylation and suggest that NPs can be included in a drug repurposing process for PCa.

ANP and BNP Exert Anti-Inflammatory Action via NPR-1/cGMP Axis by Interfering with Canonical, Non-Canonical, and Alternative Routes of Inflammasome Activation in Human THP1 Cells.

Dysregulated inflammasome activation and interleukin (IL)-1ß production are associated with several inflammatory disorders. Three different routes can lead to inflammasome activation: a canonical two-step, a non-canonical Caspase-4/5- and Gasdermin D-dependent, and an alternative Caspase-8-mediated pathway. Natriuretic Peptides (NPs), Atrial Natriuretic Peptide (ANP) and B-type Natriuretic Peptide (BNP), binding to Natriuretic Peptide Receptor-1 (NPR-1), signal by increasing cGMP (cyclic guanosine monophosphate) levels that, in turn, stimulate cGMP-dependent protein kinase-I (PKG-I). We previously demonstrated that, by counteracting inflammasome activation, NPs inhibit IL-1ß secretion. Here we aimed to decipher the molecular mechanism underlying NPs effects on THP-1 cells stimulated with lipopolysaccharide (LPS) + ATP. Involvement of cGMP and PKG-I were assessed pre-treating THP-1 cells with the membrane-permeable analogue, 8-Br-cGMP, and the specific inhibitor KT-5823, respectively. We found that NPs, by activating NPR-1/cGMP/PKG-I axis, lead to phosphorylation of NLRP3 at Ser295 and to inflammasome platform disassembly. Moreover, by increasing intracellular cGMP levels and activating phosphodiesterases, NPs interfere with both Gasdermin D and Caspase-8 cleavage, indicating that they disturb non-canonical and alternative routes of inflammasome activation. These results showed that ANP and BNP anti-inflammatory and immunomodulatory actions may involve the inhibition of all the known routes of inflammasome activation. Thus, NPs might be proposed for the treatment of the plethora of diseases caused by a dysregulated inflammasome activation.

Extracellular Vesicles-Mediated Transfer of miRNA Let-7b from PC3 Cells to Macrophages.

Prostate-derived extracellular vesicles (pEVs) may represent a way to selectively transport cargo molecules from the producing cells to the target cells to allow biological events, both in physiological and pathological circumstances. pEVs cargo participates in the modulation of the inflammatory responses in physiological conditions and during cancer progression. In the present study, we examined the expression levels of miRNA Let-7b, in both precursor and mature forms, in noncancerous and cancerous prostate cell lines, PNT2 and PC3 respectively, and in their extracellular vesicles (EVs) using reverse-transcription quantitative PCR strategies. We showed that miRNA Let-7b was highly expressed in noncancerous cells and strongly decreased in cancerous PC3 cells, while the opposite was observed in the respective EVs, thus supporting the tumor suppressor role of miRNA Let7-b. We also demonstrated that miRNA Let-7b can be transferred to THP-1 cells via EVs, which are known to induce TAM-like polarization. Our results support the view that miRNA Let-7 b, contained in PC3-derived EVs, is associated with the increase in the miRNA Let7-b observed in TAM-like macrophages. Overall, our results indicate that circulating EV-loaded miRNA might be useful biomarkers for prostate cancer progression and might also support a possible use of pEVs as targets for prostate cancer therapy.

Reductive stress in striated muscle cells.

Reductive stress is defined as a condition of sustained increase in cellular glutathione/glutathione disulfide and NADH/NAD+ ratios. Reductive stress is emerging as an important pathophysiological event in several diseased states, being as detrimental as is oxidative stress. Occurrence of reductive stress has been documented in several cardiomyopathies and is an important pathophysiological factor particularly in coronary artery disease and myocardial infarction. Excess activation of the transcription factor, Nrf2-the master regulator of the antioxidant response-, consequent in most cases to defective autophagy, can lead to reductive stress. In addition, hyperglycemia-induced activation of the polyol pathway can lead to increased NADH/NAD+ ratio, which might translate into increased levels of hydrogen sulfide-via enhanced activity of cystathionine ß-synthase-that would fuel reductive stress through inhibition of mitochondrial complex I. Reductive stress may be either a potential weapon against cancer priming tumor cells to apoptosis or a cancer's ally promoting tumor cell proliferation and making tumor cells resistant to reactive oxygen species-inducing drugs. In non-cancer pathological states reductive stress is definitely harmful paradoxically leading to reactive oxygen species overproduction via excess NADPH oxidase 4 activity. In face of the documented occurrence of reductive stress in several heart diseases, there is much less information about the occurrence and effects of reductive stress in skeletal muscle tissue. In the present review we describe relevant results emerged from studies of reductive stress in the heart and review skeletal muscle conditions in which reductive stress has been experimentally documented and those in which reductive stress might have an as yet unrecognized pathophysiological role. Establishing whether reductive stress has a (patho)physiological role in skeletal muscle will hopefully contribute to answer the question whether antioxidant supplementation to the general population, athletes, and a large cohort of patients (e.g. heart, sarcopenic, dystrophic, myopathic, cancer, and bronco-pulmonary patients) is harmless or detrimental.

Extracellular Vesicles from Human Advanced-Stage Prostate Cancer Cells Modify the Inflammatory Response of Microenvironment-Residing Cells.

Prostate cancer (PCa) progression is strictly associated with microenvironmental conditions, which can be modified by cancer-released extracellular vesicles (EVs), important mediators of cell-cell communication. However, the role of EVs in the inflammatory cross-talk between cancer cells and microenvironment-residing cells remains largely unknown. To evaluate the role of EVs in the tumour microenvironment, we treated the non-cancerous prostate cell line PNT2 with EVs isolated from advanced-stage prostate cancer PC3 (PC3-EVs). Caspase-1-mediated IL-1ß maturation was evaluated after 24 h incubation with EVs. Moreover, the effect of PC3-EVs on differentiated macrophagic THP-1 cells was assessed by analyzing cytokine expression and PC3 cells migration and proliferation profiles. We illustrated that PC3 cells contain active NLRP3-inflammasome cascade and secrete IL-1ß. PC3-EVs affect the PNT2 inflammatory response, inducing caspase-1-mediated IL-1ß maturation via ERK1/2-mediated lysosomal destabilization and cathepsin B activation. We also verified that PC3-EVs induce a functional TAM-like polarization in differentiated THP-1 cells. Our results demonstrated that cancer-derived EVs induce an inflammatory response in non-cancerous prostate cells, while inducing an immunomodulatory phenotype in immune cells. These apparently contradictory effects are both committed to strengthening the tumour-promoting microenvironment.

Cellular and molecular mechanisms of sarcopenia: the S100B perspective.

Primary sarcopenia is a condition of reduced skeletal muscle mass and strength, reduced agility, and increased fatigability and risk of bone fractures characteristic of aged, otherwise healthy people. The pathogenesis of primary sarcopenia is not completely understood. Herein, we review the essentials of the cellular and molecular mechanisms of skeletal mass maintenance; the alterations of myofiber metabolism and deranged properties of muscle satellite cells (the adult stem cells of skeletal muscles) that underpin the pathophysiology of primary sarcopenia; the role of the Ca2+ -sensor protein, S100B, as an intracellular factor and an extracellular signal regulating cell functions; and the functional role of S100B in muscle tissue. Lastly, building on recent results pointing to S100B as to a molecular determinant of myoblast-brown adipocyte transition, we propose S100B as a transducer of the deleterious effects of accumulation of reactive oxygen species in myoblasts and, potentially, myofibers concurring to the pathophysiology of sarcopenia.

Oxidative Stress in Age-Related Macular Degeneration: Nrf2 as Therapeutic Target.

Age-related macular degeneration is one of the leading causes of vision loss in the elderly. Genetics, environmental insults, and age-related issues are risk factors for the development of the disease. All these risk factors are linked to the induction of oxidative stress. In young subjects retinal pigment epithelial cells mitigate reactive oxygen generation by the elimination of dysfunctional mitochondria, via mitophagy, and by increasing antioxidant defenses via Nrf2 activation. The high amount of UV light absorbed by the retina, together with cigarette smoking, cooperate with the aging process to increase the amount of reactive oxygen species generated by retinal pigment epithelium where oxidative stress arises. Moreover, in the elderly both the mitophagic process and Nrf2 activation are impaired thus causing retinal cell death. This review will focus on the impact of oxidative stress on the pathogenesis of age-related macular degeneration and analyze the natural and synthetic Nrf2-activating compounds that have been tested as potential therapeutic agents for the disease.

Potential Influence of Cyclo(His-Pro) on Proteostasis: Impact on Neurodegenerative Diseases.

Protein function is dependent on assumption of the correct three-dimensional structure, achieved through the folding process. As a central element in ensuring cellular homeostasis, proteostasis i.e. the control of correct protein folding, trafficking and degradation, is a highly regulated process ensured by three integrated molecular pathways: i) the unfolded protein response (UPR) which is activated by the engulfment of misfolded proteins and results in protein re-folding through the expression of chaperones; ii) the ubiquitin-proteasome system (UPS) which 'flags' misfolded proteins with ubiquitin, directing them to the 26S proteasome for proteolytic degradation; iii) autophagy that, through lysosomes, removes misfolded or aggregated proteins. All three of these proteostatic controls can be impaired by the aging process and by pathological mutations highlighting the potential role of proteostasis in conditions associated with aging such as neurodegeneration, type 2 diabetes and cancer. Indeed, neurodegenerative diseases are characterised by an interconnected triumvirate of deregulated proteostasis, neuroinflammation (i.e. the uncontrolled activation of microglial cells), and oxidative stress (i.e. the unbuffered increase in reactive oxygen species). The transcription factor Nrf2, classically associated with protection against oxidative stress, can also modulate the UPR, UPS and autophagy, while inhibiting the activation of NF-kB, the key transcription factor of the inflammatory response. In this review we focus on recent data from our laboratory and others demonstrating that the protective Nrf2 pathway can be activated by the endogenous cyclic dipeptide (His-Pro), thereby driving neuroprotective effects in different pathological settings. In this context we discuss the possible utility of clyclo (His-Pro) as a promising future therapeutic option for protein misfolding disorders.

Nrf2-Keap1 signaling in oxidative and reductive stress.

Nrf2 and its endogenous inhibitor, Keap1, function as a ubiquitous, evolutionarily conserved intracellular defense mechanism to counteract oxidative stress. Sequestered by cytoplasmic Keap1 and targeted to proteasomal degradation in basal conditions, in case of oxidative stress Nrf2 detaches from Keap1 and translocates to the nucleus, where it heterodimerizes with one of the small Maf proteins. The heterodimers recognize the AREs, that are enhancer sequences present in the regulatory regions of Nrf2 target genes, essential for the recruitment of key factors for transcription. In the present review we briefly introduce the Nrf2-Keap1 system and describe Nrf2 functions, illustrate the Nrf2-NF-κB cross-talk, and highlight the effects of the Nrf2-Keap1 system in the physiology and pathophysiology of striated muscle tissue taking into account its role(s) in oxidative stress and reductive stress.

ROS-independent Nrf2 activation in prostate cancer.

In prostate cancer, oxidative stress and the subsequent Nrf2 activation promote the survival of cancer cells and acquired chemoresistance. Nrf2 links prostate cancer to endoplasmic reticulum stress, an event that triggers the unfolded protein response, aiming to restore cellular homeostasis as well as an adaptive survival mechanism. Glucose-regulated protein of 78 kD /immunoglobulin heavy chain binding protein (GRP78/BiP) is a key molecular chaperone in the endoplasmic reticulum that, when expressed at the cell surface, acts as a receptor for several signaling pathways enhancing antiapoptotic and proliferative signals. We showed GRP78/BiP translocation to PC3 cell surface in the presence of tunicamycin, an ER stress inductor, and demonstrated the existence of a GRP78/BiP-dependent non-canonical Nrf2 activation, responsible for increased resistance to ER-stress induced apoptosis. We found that, even in the absence of ROS production, tunicamycin causes Nrf2 activation, and activates Akt signaling, events bulnted by anti-GRP78/BiP antibody treatment. The presence of GRP78/BiP at the cell surface might be exploited for the immunotherapeutic strategy of prostate cancer since its blockage by anti-GRP78/BiP antibodies might promote cancer death by suppressing some of the several molecular protective mechanisms found in aggressive cancer cells.

Natriuretic Peptides: The Case of Prostate Cancer.

Cardiac natriuretic peptides have long been known to act as main players in the homeostatic control of blood pressure, salt and water balance. However, in the last few decades, new properties have been ascribed to these hormones. A systematic review of English articles using MEDLINE Search terms included prostate cancer, inflammation, cardiac hormones, atrial natriuretic peptide, and brain natriuretic peptide. Most recent publications were selected. Natriuretic peptides are strongly connected to the immune system, whose two branches, innate and adaptive, are finely tuned and organized to kill invaders and repair injured tissues. These peptides control the immune response and act as anti-inflammatory and immune-modulatory agents. In addition, in cancers, natriuretic peptides have anti-proliferative effects by molecular mechanisms based on the inhibition/regulation of several pathways promoting cell proliferation and survival. Nowadays, it is accepted that chronic inflammation is a crucial player in prostate cancer development and progression. In this review, we summarize the current knowledge on the link between prostate cancer and inflammation and the potential use of natriuretic peptides as anti-inflammatory and anticancer agents.

Adenosine in sperm physiology.

It has long been known that ATP and cAMP are deeply involved in sperm function whereas the role of adenosine and adenosine receptors is still far from being totally construed. The presence of adenosine in male reproductive tract and adenosine receptors on spermatozoa is strongly suggestive of a functional role of these receptors in sperm physiology and function. Spermatozoa are highly differentiated cells with fertility as the only goal. This paper, by an extensive review of the literature, outlines our current understanding of the role and effects of adenosine and adenosine receptors in spermatogenesis and in the acquisition of sperm fertilizing capacity which occurs in the femal genital tract, where the motile sperm fertilize an egg to form a zygote.

The Tm7sf2 Gene Deficiency Protects Mice against Endotoxin-Induced Acute Kidney Injury.

Cholesterol is essential for diverse cellular functions and cellular and whole-body cholesterol homeostasis is highly controlled. Cholesterol can also influence cellular susceptibility to injury. The connection between cholesterol metabolism and inflammation is exemplified by the Tm7sf2 gene, the absence of which reveals an essential role in cholesterol biosynthesis under stress conditions but also results in an inflammatory phenotype, i.e. NF-κB activation and TNFα up-regulation. Here, by using Tm7sf2+/+and Tm7sf2-/- mice, we investigated whether the Tm7sf2 gene, through its role in cholesterol biosynthesis under stress conditions, is involved in the renal failure induced by the administration of LPS. We found that the loss of Tm7sf2 gene results in significantly reduced blood urea nitrogen levels accompanied by decreased renal inflammatory response and neutral lipid accumulation. The increased expression of fatty acids catabolic enzymes reduces the need of the renal autophagy, a known crucial nutrient-sensing pathway in lipid metabolism. Moreover, we observed that the Tm7sf2 insufficiency is responsible for the inhibition of the NF-κB signalling thus dampening the inflammatory response and leading to a reduced renal damage. These results suggest a pivotal role for Tm7sf2 in renal inflammatory and lipotoxic response under endotoxemic conditions.