FEMaLe: The use of machine learning for early diagnosis of endometriosis based on patient self-reported data-Study protocol of a multicenter trial.

INTRODUCTION: Endometriosis is a chronic disease that affects up to 190 million women and those assigned female at birth and remains unresolved mainly in terms of etiology and optimal therapy. It is defined by the presence of endometrium-like tissue outside the uterine cavity and is commonly associated with chronic pelvic pain, infertility, and decreased quality of life. Despite the availability of various screening methods (e.g., biomarkers, genomic analysis, imaging techniques) intended to replace the need for invasive surgery, the time to diagnosis remains in the range of 4 to 11 years. AIMS: This study aims to create a large prospective data bank using the Lucy mobile health application (Lucy app) and analyze patient profiles and structured clinical data. In addition, we will investigate the association of removed or restricted dietary components with quality of life, pain, and central pain sensitization. METHODS: A baseline and a longitudinal questionnaire in the Lucy app collects real-world, self-reported information on symptoms of endometriosis, socio-demographics, mental and physical health, economic factors, nutritional, and other lifestyle factors. 5,000 women with confirmed endometriosis and 5,000 women without diagnosed endometriosis in a control group will be enrolled and followed up for one year. With this information, any connections between recorded symptoms and endometriosis will be analyzed using machine learning. CONCLUSIONS: We aim to develop a phenotypic description of women with endometriosis by linking the collected data with existing registry-based information on endometriosis diagnosis, healthcare utilization, and big data approach. This may help to achieve earlier detection of endometriosis with pelvic pain and significantly reduce the current diagnostic delay. Additionally, we may identify dietary components that worsen the quality of life and pain in women with endometriosis, upon which we can create real-world data-based nutritional recommendations.

Cardioprotective and Antifibrotic Effects of Low-Dose Renin-Angiotensin-Aldosterone System Inhibitors in Type 1 Diabetic Rat Model.

Diabetic cardiovascular complications are associated with up to 50% mortality, and current therapies are not effective enough. Renin-angiotensin-aldosterone system inhibitors (RAASis) are the standard of care for diabetic patients with hypertension and albuminuria. Based on our previous studies reporting the renoprotective effects of low-dose RAASis, here, we hypothesized that low-dose RAASi treatment has cardioprotective and antifibrotic benefits in type 1 diabetes mellitus (T1DM). After five weeks of T1DM, adult male Wistar rats received low doses of ramipril, losartan, or eplerenone for two weeks. Heart rate, blood pressure, and pulse wave velocity (PWV) were recorded. Aortic intima-media thickness (IMT), collagen accumulation, and myocardial fibrosis were assessed. All RAASis reduced PWV elevation, prevented the progression of myocardial fibrosis, and normalized B-type natriuretic peptide, troponin I, and fibroblast growth factor 23 levels without affecting blood pressure. Interestingly, only eplerenone reversed the decline in Klotho levels and reduced IMT and fibrosis in the media of the aorta. Our comparative analysis suggests that mineralocorticoid receptor antagonists, particularly eplerenone, may offer superior efficacy in halting both the arterial and the myocardial injuries in T1DM compared to angiotensin-converting enzyme inhibitors or angiotensin II type 1 receptor blockers.

An Overview of the Cardioprotective Effects of Novel Antidiabetic Classes: Focus on Inflammation, Oxidative Stress, and Fibrosis.

Metabolic diseases, particularly diabetes mellitus (DM), are significant global public health concerns. Despite the widespread use of standard-of-care therapies, cardiovascular disease (CVD) remains the leading cause of death among diabetic patients. Early and evidence-based interventions to reduce CVD are urgently needed. Large clinical trials have recently shown that sodium-glucose cotransporter-2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor agonists (GLP-1RA) ameliorate adverse cardiorenal outcomes in patients with type 2 DM. These quite unexpected positive results represent a paradigm shift in type 2 DM management, from the sole importance of glycemic control to the simultaneous improvement of cardiovascular outcomes. Moreover, SGLT2i is also found to be cardio- and nephroprotective in non-diabetic patients. Several mechanisms, which may be potentially independent or at least separate from the reduction in blood glucose levels, have already been identified behind the beneficial effect of these drugs. However, there is still much to be understood regarding the exact pathomechanisms. This review provides an overview of the current literature and sheds light on the modes of action of novel antidiabetic drugs, focusing on inflammation, oxidative stress, and fibrosis.

Listeria monocytogenes utilizes the ClpP1/2 proteolytic machinery for fine-tuned substrate degradation at elevated temperatures.

Listeria monocytogenes exhibits two ClpP isoforms (ClpP1/ClpP2) which assemble into a heterooligomeric complex with enhanced proteolytic activity. Herein, we demonstrate that the formation of this complex depends on temperature and reaches a maximum ratio of about 1 : 1 at 30 °C, while almost no complex formation occurred below 4 °C. In order to decipher the role of the two isoforms at elevated temperatures, we constructed L. monocytogenes ClpP1, ClpP2 and ClpP1/2 knockout strains and analyzed their protein regulation in comparison to the wild type (WT) strain via whole proteome mass-spectrometry (MS) at 37 °C and 42 °C. While the ΔclpP1 strain only altered the expression of very few proteins, the ΔclpP2 and ΔclpP1/2 strains revealed the dysregulation of many proteins at both temperatures. These effects were corroborated by crosslinking co-immunoprecipitation MS analysis. Thus, while ClpP1 serves as a mere enhancer of protein degradation in the heterocomplex, ClpP2 is essential for ClpX binding and functions as a gatekeeper for substrate entry. Applying an integrated proteomic approach combining whole proteome and co-immunoprecipitation datasets, several putative ClpP2 substrates were identified in the context of different temperatures and discussed with regards to their function in cellular pathways such as the SOS response.

SGLT2 inhibitor dapagliflozin prevents atherosclerotic and cardiac complications in experimental type 1 diabetes.

INTRODUCTION: Cardiovascular disease (CVD) is two to five times more prevalent in diabetic patients and is the leading cause of death. Therefore, identification of novel therapeutic strategies that reduce the risk of CVD is a research priority. Clinical trials showed that reduction in the relative risk of heart failure by sodium-glucose cotransporter 2 inhibitors (SGLT2i) are partly beyond their glucose lowering effects, however, the molecular mechanisms are still elusive. Here we investigated the role of SGLT2i dapagliflozin (DAPA) in the prevention of diabetes-induced cardiovascular complications. METHODS: Type 1 diabetes was induced with streptozotocin (65 mg/bwkg, ip.) in adult, male Wistar rats. Following the onset of diabetes rats were treated for six weeks with DAPA (1 mg/bwkg/day, po.). RESULTS: DAPA decreased blood glucose levels (D: 37±2.7 vs. D+DAPA: 18±5.6 mmol/L; p<0.05) and prevented metabolic decline. Aortic intima-media thickening was mitigated by DAPA. DAPA abolished cardiac hypertrophy, and myocardial damage. Cardiac inflammation and fibrosis were also moderated after DAPA treatment. CONCLUSIONS: These data support the preventive and protective role of SGLT2i in diabetes-associated cardiovascular disease. SGLT2i may provide novel therapeutic strategy to hinder the development of cardiovascular diseases in type 1 diabetes, thereby improve the outcomes.

Non-covalently embedded oxytocin in alkanethiol monolayer as Zn2+ selective biosensor.

Peptides are commonly used as biosensors for analytes such as metal ions as they have natural binding preferences. In our previous peptide-based impedimetric metal ion biosensors, a monolayer of the peptide was anchored covalently to the electrode. Binding of metal ions resulted in a conformational change of the oxytocin peptide in the monolayer, which was measured using electrochemical impedance spectroscopy. Here, we demonstrate that sensing can be achieved also when the oxytocin is non-covalently integrated into an alkanethiol host monolayer. We show that ion-binding cause morphological changes to the dense host layer, which translates into enhanced impedimetric signals compared to direct covalent assembly strategies. This biosensor proved selective and sensitive for Zn2+ ions in the range of nano- to micro-molar concentrations. This strategy offers an approach to utilize peptide flexibility in monitoring their response to the environment while embedded in a hydrophobic monolayer.

Antidepressant effect in diabetes-associated depression: A novel potential of RAAS inhibition.

The incidence of depression doubles in diabetic patients and is associated with poor outcomes. Studies indicate that renin-angiotensin-aldosterone system inhibitors (RAASi) might relieve depression, however the mechanism of action is not well understood. We recently showed that angiotensin receptor blockers have antidepressant effects in experimental diabetes comorbid depression. Here we investigated whether all types of RAASi exhibit antidepressant and neuroprotective properties. Diabetes was induced by streptozotocin in adult male Wistar rats. After 5 weeks of diabetes, rats were treated per os with non-pressor doses of enalapril, ramipril, spironolactone or eplerenone for 2 weeks. Behavior was evaluated using forced swim test and open field test. Inflammatory response and brain-derived neurotrophic factor (BDNF) signaling were investigated in the hippocampus. Both ACEi and MR antagonists reversed diabetes-induced behavioral despair confirming their antidepressant-like effect. This may occur via alterations in hippocampal cytokine-mediated inflammatory response. Repressed BDNF production was restored by RAASi. Both ACEi and MR antagonists facilitated the BDNF-tropomyosin receptor kinase B-cAMP response element-binding protein signaling pathway as part of their neuroprotective effect. These data highlight the important benefits of ACEi and MR antagonists in the treatment of diabetes-associated depressive symptoms. Our novel findings support the link between diabetes comorbid depression, inflammation and repressed BDNF signaling. RAASi could provide new therapeutic options to improve the outcomes of both disorders.

Reduced O-GlcNAcylation and tubular hypoxia contribute to the antifibrotic effect of SGLT2 inhibitor dapagliflozin in the diabetic kidney.

Diabetic kidney disease is a worldwide epidemic, and therapies are incomplete. Clinical data suggest that improved renal outcomes by Na+-glucose cotransporter 2 inhibitor (SGLT2i) are partly beyond their antihyperglycemic effects; however, the mechanisms are still elusive. Here, we investigated the effect of the SGLT2i dapagliflozin (DAPA) in the prevention of elevated O-GlcNAcylation and tubular hypoxia as contributors of renal fibrosis. Type 1 diabetes was induced by streptozotocin in adult male Wistar rats. After the onset of diabetes, rats were treated for 6 wk with DAPA or DAPA combined with losartan (LOS). The effect of hyperglycemia was tested in HK-2 cells kept under normal or high glucose conditions. To test the effect of hypoxia, cells were kept in 1% O2 for 2 h. Cells were treated with DAPA or DAPA combined with LOS. DAPA slowed the loss of renal function, mitigated renal tubular injury markers (kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin), and reduced tubulointerstitial fibrosis. DAPA diminished high glucose-induced protein O-GlcNAcylation and moderated the tubular response to hypoxia through the hypoxia-inducible factor pathway. DAPA alone was as effective as combined treatment with LOS in all outcome parameters. These data highlight the role of ameliorated O-GlcNAcylation and diminished tubular hypoxia as important benefits of SGLT2i treatment. Our results support the link between glucose toxicity, tubular hypoxia, and fibrosis, a vicious trio that could be targeted by SGLT2i in kidney diseases of other origins as well.

Cryo-EM structure of the ClpXP protein degradation machinery.

The ClpXP machinery is a two-component protease complex that performs targeted protein degradation in bacteria and mitochondria. The complex consists of the AAA+ chaperone ClpX and the peptidase ClpP. The hexameric ClpX utilizes the energy of ATP binding and hydrolysis to engage, unfold and translocate substrates into the catalytic chamber of tetradecameric ClpP, where they are degraded. Formation of the complex involves a symmetry mismatch, because hexameric AAA+ rings bind axially to the opposing stacked heptameric rings of the tetradecameric ClpP. Here we present the cryo-EM structure of ClpXP from Listeria monocytogenes. We unravel the heptamer-hexamer binding interface and provide novel insight into the ClpX-ClpP cross-talk and activation mechanism. Comparison with available crystal structures of ClpP and ClpX in different states allows us to understand important aspects of the complex mode of action of ClpXP and provides a structural framework for future pharmacological applications.

Novel therapeutic potential of angiotensin receptor 1 blockade in a rat model of diabetes-associated depression parallels altered BDNF signalling.

AIMS/HYPOTHESIS: Diabetes is a worldwide epidemic linked with diverse diseases of the nervous system, including depression. A few studies suggested a connection between renin-angiotensin-aldosterone system blockers and reduced depressive symptoms, although underlying mechanisms are unclear. Here we investigated the antidepressant effect and the mechanisms of action of the angiotensin receptor 1 blocker (ARB) losartan in an experiential model of diabetes-associated depression. METHODS: Experimental diabetes was induced by streptozotocin in adult male Wistar rats. After 5 weeks of diabetes, rats were treated for 2 weeks with a non-pressor oral dose of losartan (20 mg/kg). In protocol 1, cerebrovascular perfusion and glial activation were evaluated by single-photon emission computed tomography-MRI and immunohistochemistry. In protocol 2, behaviour studies were performed (forced swim test and open field test). Hippocampal proinflammatory response and brain-derived neurotrophic factor (BDNF) signalling were also assessed. RESULTS: Here, we show that diabetic rats exhibit depression-like behaviour, which can be therapeutically reversed by losartan. This action of losartan occurs via changes in diabetes-induced neuroinflammatory responses rather than altered cerebral perfusion. We also show that as a part of its protective effect losartan restores BDNF production in astrocytes and facilitates BDNF-tropomyosin receptor kinase B-cAMP response element-binding protein signalling in the diabetic brain. CONCLUSIONS/INTERPRETATION: We identified a novel effect of losartan in the nervous system that may be implemented to alleviate symptoms of diabetes-associated depression. These findings explore a new therapeutic horizon for ARBs as possible antidepressants and suggest that BDNF could be a target of future drug development in diabetes-induced complications.

Tailored Peptide Phenyl Esters Block ClpXP Proteolysis by an Unusual Breakdown into a Heptamer-Hexamer Assembly.

The proteolytic complex ClpXP is fundamental to bacterial homeostasis and pathogenesis. Because of its conformational flexibility, the development of potent ClpXP inhibitors is challenging, and novel tools to decipher its intricate regulation are urgently needed. Herein, we present amino acid based phenyl esters as molecular probes to study the activity and oligomerization of the ClpXP complex of S. aureus. Systematic screening of (R)- and (S)-amino acids led to compounds showing potent inhibition, as well as stimulation of ClpXP-mediated proteolysis. Substoichiometric binding of probes arrested ClpXP in an unprecedented heptamer-hexamer assembly, in which the two heptameric ClpP rings are dissociated from each other. At the same time, the affinity between ClpX and ClpP increased, leading to inhibition of both enzymes. This conformational arrest is beneficial for the consolidated shutdown of ClpXP, as well as for the study of the oligomeric state during its catalytic cycle.

RAAS inhibitors directly reduce diabetes-induced renal fibrosis via growth factor inhibition.

KEY POINTS: Increased activation of the renin-angiotensin-aldosterone system (RAAS) and elevated growth factor production are of crucial importance in the development of renal fibrosis leading to diabetic kidney disease. The aim of this study was to provide evidence for the antifibrotic potential of RAAS inhibitor (RAASi) treatment and to explore the exact mechanism of this protective effect. We found that RAASi ameliorate diabetes-induced renal interstitial fibrosis and decrease profibrotic growth factor production. RAASi prevents fibrosis by acting directly on proximal tubular cells, and inhibits hyperglycaemia-induced growth factor production and thereby fibroblast activation. These results suggest a novel therapeutic indication and potential of RAASi in the treatment of renal fibrosis. ABSTRACT: In diabetic kidney disease (DKD) increased activation of renin-angiotensin-aldosterone system (RAAS) contributes to renal fibrosis. Although RAAS inhibitors (RAASi) are the gold standard therapy in DKD, the mechanism of their antifibrotic effect is not yet clarified. Here we tested the antifibrotic and renoprotective action of RAASi in a rat model of streptozotocin-induced DKD. In vitro studies on proximal tubular cells and renal fibroblasts were also performed to further clarify the signal transduction pathways that are directly altered by hyperglycaemia. After 5 weeks of diabetes, male Wistar rats were treated for two more weeks per os with the RAASi ramipril, losartan, spironolactone or eplerenone. Proximal tubular cells were cultured in normal or high glucose (HG) medium and treated with RAASi. Platelet-derived growth factor (PDGF) or connective tissue growth factor (CTGF/CCN2)-induced renal fibroblasts were also treated with various RAASi. In diabetic rats, reduced renal function and interstitial fibrosis were ameliorated and elevated renal profibrotic factors (TGFß1, PDGF, CTGF/CCN2, MMP2, TIMP1) and alpha-smooth muscle actin (αSMA) levels were decreased by RAASi. HG increased growth factor production of HK-2 cells, which in turn induced activation and αSMA production of fibroblasts. RAASi decreased tubular PDGF and CTGF expression and reduced production of extracellular matrix (ECM) components in fibroblasts. In proximal tubular cells, hyperglycaemia-induced growth factor production increased renal fibroblast transformation, contributing to the development of fibrosis. RAASi, even in non-antihypertensive doses, decreased the production of profibrotic factors and directly prevented fibroblast activation. All these findings suggest a novel therapeutic role for RAASi in the treatment of renal fibrosis.

Selective Activation of Human Caseinolytic Protease†P (ClpP).

Caseinolytic protease P (ClpP) is the proteolytic component of the ClpXP protein degradation complex. Eukaryotic ClpP was recently found to act within the mitochondria-specific unfolded protein response (UPRmt ). However, its detailed function and dedicated regulation remain largely unexplored. A small molecule (D9) acts as a potent and species-selective activator of human ClpP (hClpP) by mimicking the natural chaperone ClpX. Structure-activity relationship studies highlight the importance of a halogenated benzyl motif within D9 that interacts with a unique aromatic amino acid network in hClpP. Mutational and structural studies suggest that this YYW motif tightly controls hClpP activity and regulates substrate turnover by interaction with cognate ligands. This signature motif is unique to ClpP from higher organisms and does not exist in tested bacterial homologues, allowing a species-selective analysis. Thus, D9 is a versatile tool to analyze mechanistic features of hClpP.

The role of Sigma-1 receptor in sex-specific heat shock response in an experimental rat model of renal ischaemia/reperfusion injury.

We previously showed that female rats are more protected against renal ischaemia/reperfusion (I/R) injury than males, which is partly attributed to their more pronounced heat shock response. We recently described that Sigma-1 receptor (S1R) activation improves postischaemic survival and renal function. 17ß-estradiol activates S1R, thus here we investigated the role of sex-specific S1R activation and heat shock response in severe renal I/R injury. Proximal tubular cells were treated with 17ß-estradiol, which caused direct S1R activation and subsequent induction of heat shock response. Uninephrectomized female, male and ovariectomized female (Ovx) Wistar rats were subjected to 50-min renal ischaemia followed by 2 (T2) and 24 (T24) hours of reperfusion. At T24 renal functional, impairment was less severe and structural damage was less prominent in females versus males or Ovx. Postischaemic increase in S1R, pAkt, HSF-1, HSP72 levels were detected as early as at T2, while pHSP27 was elevated later at T24. Abundance of heat shock proteins was higher in healthy female rats and remained higher at T2 and T24 (female versus male or Ovx; resp.). We propose a S1R-dependent mechanism, which contributes to the relative renoprotection of females after I/R injury by enhancing the heat shock response.

Insights into ClpXP proteolysis: heterooligomerization and partial deactivation enhance chaperone affinity and substrate turnover in Listeria monocytogenes.

Caseinolytic proteases (ClpP) are important for recognition and controlled degradation of damaged proteins. While the majority of bacterial organisms utilize only a single ClpP, Listeria monocytogenes expresses two isoforms (LmClpP1 and LmClpP2). LmClpPs assemble into either a LmClpP2 homocomplex or a LmClpP1/2 heterooligomeric complex. The heterocomplex in association with the chaperone ClpX, exhibits a boost in proteolytic activity for unknown reasons. Here, we use a combined chemical and biochemical strategy to unravel two activation principles of LmClpPs. First, determination of apparent affinity constants revealed a 7-fold elevated binding affinity between the LmClpP1/2 heterocomplex and ClpX, compared to homooligomeric LmClpP2. This tighter interaction favors the formation of the proteolytically active complex between LmClpX and LmClpP1/2 and thereby accelerating the overall turnover. Second, screening a diverse library of fluorescent labeled peptides and proteins with various ClpP mutants allowed the individual analysis of substrate preferences for both isoforms within the heterocomplex. In addition to Leu and Met, LmClpP2 preferred a long aliphatic chain (2-Aoc) in the P1 position for cleavage. Strikingly, design and synthesis of a corresponding 2-Aoc chloromethyl ketone inhibitor resulted in stimulation of proteolysis by 160% when LmClpP2 was partially alkylated on 20% of the active sites. Determination of apparent affinity constants also revealed an elevated complex stability between partially modified LmClpP2 and the cognate chaperone LmClpX. Thus, the stimulation of proteolysis through enhanced binding to the chaperone seems to be a characteristic feature of LmClpPs.

σ1-Receptor Agonism Protects against Renal Ischemia-Reperfusion Injury.

Mechanisms of renal ischemia-reperfusion injury remain unresolved, and effective therapies are lacking. We previously showed that dehydroepiandrosterone protects against renal ischemia-reperfusion injury in male rats. Here, we investigated the potential role of σ1-receptor activation in mediating this protection. In rats, pretreatment with either dehydroepiandrosterone or fluvoxamine, a high-affinity σ1-receptor agonist, improved survival, renal function and structure, and the inflammatory response after sublethal renal ischemia-reperfusion injury. In human proximal tubular epithelial cells, stimulation by fluvoxamine or oxidative stress caused the σ1-receptor to translocate from the endoplasmic reticulum to the cytosol and nucleus. Fluvoxamine stimulation in these cells also activated nitric oxide production that was blocked by σ1-receptor knockdown or Akt inhibition. Similarly, in the postischemic rat kidney, σ1-receptor activation by fluvoxamine triggered the Akt-nitric oxide synthase signaling pathway, resulting in time- and isoform-specific endothelial and neuronal nitric oxide synthase activation and nitric oxide production. Concurrently, intravital two-photon imaging revealed prompt peritubular vasodilation after fluvoxamine treatment, which was blocked by the σ1-receptor antagonist or various nitric oxide synthase blockers. In conclusion, in this rat model of ischemia-reperfusion injury, σ1-receptor agonists improved postischemic survival and renal function via activation of Akt-mediated nitric oxide signaling in the kidney. Thus, σ1-receptor activation might provide a therapeutic option for renoprotective therapy.

Role of O-linked N-acetylglucosamine modification in diabetic nephropathy.

Increased O-linked ß-N-acetylglucosamine glycosylation (O-GlcNAcylation) is a known contributor to diabetes; however, its relevance in diabetic nephropathy (DN) is poorly elucidated. Here, we studied the process and enzymes of O-GlcNAcylation with a special emphasis on Akt-endothelial nitric oxide synthase (eNOS) and heat shock protein (HSP)72 signaling. Since tubular injury is the prominent site of DN, the effect of hyperglycemia was first measured in proximal tubular (HK2) cells cultured in high glucose. In vivo O-GlcNAcylation and protein levels of O-GlcNAc transferase (OGT), O-GlcNAcase (OGA), phosphorylated (p)Akt/Akt, peNOS/eNOS, and HSP72 were assessed in the kidney cortex of streptozotocin-induced diabetic rats. The effects of various renin-angiotensin-aldosterone system (RAAS) inhibitors were also evaluated. In proximal tubular cells, hyperglycemia-induced OGT expression led to increased O-GlcNAcylation, which was followed by a compensatory increase of OGA. In parallel, peNOS and pAkt levels decreased, whereas HSP72 increased. In diabetic rats, elevated O-GlcNAcylation was accompanied by decreased OGT and OGA. RAAS inhibitors ameliorated diabetes-induced kidney damage and prevented the elevation of O-GlcNAcylation and the decrement of pAkt, peNOS, and HSP72. In conclusion, hyperglycemia-induced elevation of O-GlcNAcylation contributes to the progression of DN via inhibition of Akt/eNOS phosphorylation and HSP72 induction. RAAS blockers successfully inhibit this process, suggesting a novel pathomechanism of their renoprotective action in the treatment of DN.

The role of sigma-1 receptor and brain-derived neurotrophic factor in the development of diabetes and comorbid depression in streptozotocin-induced diabetic rats.

RATIONALE: Depression is highly prevalent in diabetes (DM). Brain-derived neurotrophic factor (BDNF) which is mainly regulated by the endoplasmic reticulum chaperon sigma-1 receptor (S1R) plays a relevant role in the development of depression. OBJECTIVES: We studied the dose-dependent efficacy of S1R agonist fluvoxamine (FLU) in the prevention of DM-induced depression and investigated the significance of the S1R-BDNF pathway. METHODS: We used streptozotocin to induce DM in adult male rats that were treated for 2 weeks p.o. with either different doses of FLU (2 or 20 mg/bwkg) or FLU + S1R antagonist NE100 (1 mg/bwkg) or vehicle. Healthy controls were also enrolled. Metabolic, behaviour, and neuroendocrine changes were determined, and S1R and BDNF levels were measured in the different brain regions. RESULTS: In DM rats, immobility time was increased, adrenal glands were enlarged, and thymuses were involuted. FLU in 20 mg/bwkg, but not in 2 mg/bwkg dosage, ameliorated depression-like behaviour. S1R and BDNF protein levels were decreased in DM, while FLU induced SIR-BDNF production. NE100 suspended all effects of FLU. CONCLUSIONS: We suggest that disturbed S1R-BDNF signaling in the brain plays a relevant role in DM-induced depression. The activation of this cascade serves as an additional target in the prevention of DM-associated depression.

Programmed Synthesis by Stimuli-Responsive DNAzyme-Modified Mesoporous SiO2 Nanoparticles.

DNAzyme-capped mesoporous SiO2 nanoparticles (MP SiO2 NPs) are applied as stimuli-responsive containers for programmed synthesis. Three types of MP SiO2 NPs are prepared by loading the NPs with Cy3-DBCO (DBCO=dibenzocyclooctyl), Cy5-N3 , and Cy7-N3 , and capping the NP containers with the Mg(2+) , Zn(2+) , and histidine-dependent DNAzyme sequences, respectively. In the presence of Mg(2+) and Zn(2+) ions as triggers, the respective DNAzyme-capped NPs are unlocked, leading to the "click" reaction product Cy3-Cy5. In turn, in the presence of Mg(2+) ions and histidine as triggers the second set of DNAzyme-capped NPs is unlocked leading to the Cy3-Cy7 conjugated product. The unloading of the respective NPs and the time-dependent formation of the products are followed by fluorescence spectroscopy (FRET). A detailed kinetic model for the formation of the different products is formulated and it correlates nicely with the experimental results.

DNA sensors and aptasensors based on the hemin/G-quadruplex-controlled aggregation of Au NPs in the presence of L-cysteine.

L-cysteine induces the aggregation of Au nanoparticles (NPs), resulting in a color transition from red to blue due to interparticle plasmonic coupling in the aggregated structure. The hemin/G-quadruplex horseradish peroxidase-mimicking DNAzyme catalyzes the aerobic oxidation of L-cysteine to cystine, a process that inhibits the aggregation of the NPs. The degree of inhibition of the aggregation process is controlled by the concentration of the DNAzyme in the system. These functions are implemented to develop sensing platforms for the detection of a target DNA, for the analysis of aptamer-substrate complexes, and for the analysis of L-cysteine in human urine samples. A hairpin DNA structure that includes a recognition site for the DNA analyte and a caged G-quadruplex sequence, is opened in the presence of the target DNA. The resulting self-assembled hemin/G-quadruplex acts as catalyst that controls the aggregation of the Au NPs. Also, the thrombin-binding aptamer folds into a G-quadruplex nanostructure upon binding to thrombin. The association of hemin to the resulting G-quadruplex aptamer-thrombin complex leads to a catalytic label that controls the L-cysteine-mediated aggregation of the Au NPs. The hemin/G-qaudruplex-controlled aggregation of Au NPs process is further implemented for visual and spectroscopic detection of L-cysteine concentration in urine samples.