Matrix metalloproteinases mediate influenza A-associated shedding of the alveolar epithelial glycocalyx.

BACKGROUND: The alveolar epithelium is protected by a heparan sulfate-rich, glycosaminoglycan layer called the epithelial glycocalyx. It is cleaved in patients with acute respiratory distress syndrome (ARDS) and in murine models of influenza A (IAV) infection, shedding fragments into the airspace from the cell surface. Glycocalyx shedding results in increased permeability of the alveolar-capillary barrier, amplifying acute lung injury. The mechanisms underlying alveolar epithelial glycocalyx shedding in IAV infection are unknown. We hypothesized that induction of host sheddases such as matrix metalloproteinases (MMPs) during IAV infection results in glycocalyx shedding and increased lung injury. MATERIALS AND METHODS: We measured glycocalyx shedding and lung injury during IAV infection with and without treatment with the pan-MMP inhibitor Ilomastat (ILO) and in an MMP-7 knock out (MMP-7KO) mouse. C57BL/6 or MMP-7KO male and female mice were given IAV A/PR/8/34 (H1N1) at 30,000 PFU/mouse or PBS intratracheally. For some experiments, C56BL/6 mice were infected in the presence of ILO (100mg/kg) or vehicle given daily by IP injection. Bronchoalveolar lavage (BAL) and lung tissue were collected on day 1, 3, and 7 for analysis of glycocalyx shedding (BAL Syndecan-1) and lung injury (histology, BAL protein, BAL cytokines, BAL immune cell infiltrates, BAL RAGE). Expression and localization of the sheddase MMP-7 and its inhibitor TIMP-1 was examined by RNAScope. For in vitro experiments, MLE-12 mouse lung epithelial cells were cultured and treated with active or heat-inactivated heparinase (2.5 U/mL) prior to infection with IAV (MOI 1) and viral load and MMP-7 and TIMP-1 expression analyzed. RESULTS: IAV infection caused shedding of the epithelial glycocalyx into the BAL. Inhibition of MMPs with ILO reduced glycocalyx shedding by 36% (p = 0.0051) and reduced lung epithelial injury by 40% (p = 0.0404). ILO also reduced viral load by 68% (p = 0.027), despite having no significant effect on lung cytokine production. Both MMP-7 and its inhibitor TIMP-1 were upregulated in IAV infected mice: MMP-7 colocalized with IAV, while TIMP-1 was limited to cells adjacent to infection. However, MMP-7KO mice had similar glycocalyx shedding, epithelial injury, and viral load compared to WT littermates, suggesting redundancy in MMP sheddase function in the lung. In vitro, heparinase treatment before infection led to a 52% increase in viral load (p = 0.0038) without altering MMP-7 or TIMP-1 protein levels. CONCLUSIONS: Glycocalyx shedding and MMPs play key roles in IAV-induced epithelial injury, with significant impact on IAV viral load. Further studies are needed to understand which specific MMPs regulate lung epithelial glycocalyx shedding.

South American monsoon intensification during the last millennium driven by joint Pacific and Atlantic forcing.

The South American summer monsoon (SASM) profoundly influences tropical South America's climate, yet understanding its low-frequency variability has been challenging. Climate models and oxygen isotope data have been used to examine the SASM variability over the last millennium (LM) but have, at times, provided conflicting findings, especially regarding its mean-state change from the Medieval Climate Anomaly to the Little Ice Age. Here, we use a paleoclimate data assimilation (DA) method, combining model results and δ18O observations, to produce a δ18O-enabled, dynamically coherent, and spatiotemporally complete austral summer hydroclimate reconstruction over the LM for tropical South America at 5-year resolution. This reconstruction aligns with independent hydroclimate and δ18O records withheld from the DA, revealing a centennial-scale SASM intensification during the MCA-LIA transition period, associated with the southward shift of the Atlantic Intertropical Convergence Zone and the strengthening Pacific Walker circulation (PWC). This highlights the necessity of accurately representing the PWC in climate models to predict future SASM changes.

Does HLA explain the high incidence of childhood-onset type 1 diabetes in the Canary Islands? The role of Asp57 DQB1 molecules.

The Canary Islands inhabitants, a recently admixed population with significant North African genetic influence, has the highest incidence of childhood-onset type 1 diabetes (T1D) in Spain and one of the highest in Europe. HLA accounts for half of the genetic risk of T1D. AIMS: To characterize the classical HLA-DRB1 and HLA-DQB1 alleles in children from Gran Canaria with and without T1D. METHODS: We analyzed classic HLA-DRB1 and HLA-DQB1 alleles in childhood-onset T1D patients (n = 309) and control children without T1D (n = 222) from the island of Gran Canaria. We also analyzed the presence or absence of aspartic acid at position 57 in the HLA-DQB1 gene and arginine at position 52 in the HLA-DQA1 gene. Genotyping of classical HLA-DQB1 and HLA-DRB1 alleles was performed at two-digit resolution using Luminex technology. The chi-square test (or Fisher's exact test) and odds ratio (OR) were computed to assess differences in allele and genotype frequencies between patients and controls. Logistic regression analysis was also used. RESULTS: Mean age at diagnosis of T1D was 7.4 ± 3.6 years (46% female). Mean age of the controls was 7.6 ± 1.1 years (55% female). DRB1*03 (OR = 4.2; p = 2.13-13), DRB1*04 (OR = 6.6; p ≤ 2.00-16), DRB1* 07 (OR = 0.37; p = 9.73-06), DRB1*11 (OR = 0.17; p = 6.72-09), DRB1*12, DRB1*13 (OR = 0.38; p = 1.21-05), DRB1*14 (OR = 0.0; p = 0.0024), DRB1*15 (OR = 0.13; p = 7.78-07) and DRB1*16 (OR = 0.21; p = 0.003) exhibited significant differences in frequency between groups. Among the DQB1* alleles, DQB1*02 (OR: 2.3; p = 5.13-06), DQB1*03 (OR = 1.7; p = 1.89-03), DQB1*05 (OR = 0.64; p = 0.027) and DQB1*06 (OR = 0.19; p = 6.25-14) exhibited significant differences. A total of 58% of the studied HLA-DQB1 genes in our control population lacked aspartic acid at position 57. CONCLUSIONS: In this population, the overall distributions of the HLA-DRB1 and HLA-DQB1 alleles are similar to those in other European populations. However, the frequency of the non-Asp-57 HLA-DQB1 molecules is greater than that in other populations with a lower incidence of T1D. Based on genetic, historical and epidemiological data, we propose that a common genetic background might help explain the elevated pediatric T1D incidence in the Canary Islands, North-Africa and middle eastern countries.

Acute effects of lower limb wearable resistance on horizontal deceleration and change of direction biomechanics.

This study aimed to investigate the acute effects of lower limb wearable resistance on maximal horizontal deceleration biomechanics, across two different assessments. Twenty recreationally trained team sport athletes performed acceleration to deceleration assessments (ADA), and 5-0-5 change of direction (COD) tests across three load conditions (unloaded, 2% of BW, 4% of body weight (BW)), with load attached to the anterior and posterior thighs and shanks. Linear mixed effect models with participant ID as the random effect, and load condition as the fixed effect were used to study load-specific biomechanical differences in deceleration mechanics across both tests. Primary study findings indicate that for the ADA, in the 4% BW condition, participants exhibited significantly greater degrees of Avg Approach Momentum, as well as significant reductions in deceleration phase center of mass (COM) drop, and Avg Brake Step ground contact deceleration (GCD) in both the 2% BW, and 4% BW condition, compared to the unloaded condition. In the 5-0-5 tests, participants experienced significant reductions in Avg Approach Velocity, Avg deceleration (DEC), and Stopping Time in the 4% BW condition compared to the unloaded condition. Similar to the ADA test, participants also experienced significant reductions in Avg Brake Step GCD in both the 2% BW and 4% BW conditions, and significant increases in Avg Approach Momentum in the 4% BW condition, compared to the unloaded condition. Therefore, findings suggest that based on the test, and metric of interest, the addition of lower limb wearable resistance led to acute differences in maximal horizontal deceleration biomechanics. However, future investigations are warranted to further explore if the use of lower limb wearable resistance could present as an effective training tool in enhancing athlete's horizontal deceleration and change of direction performance.

Biological reliability of a movement analysis assessment using a markerless motion capture system.

Introduction: Advances in motion capture technology include markerless systems to facilitate valid data collection. Recently, the technological reliability of this technology has been reported for human movement assessments. To further understand sources of potential error, biological reliability must also be determined. The aim of this study was to determine the day-to-day reliability for a three-dimensional markerless motion capture (MMC) system to quantify 4 movement analysis composite scores, and 81 kinematic variables. Methods: Twenty-two healthy men (n = 11; X ¯ ± SD ; age = 23.0 ± 2.6 years, height = 180.4.8 cm, weight = 80.4 ± 7.3 kg) and women (n = 11; age = 20.8 ± 1.1 years, height = 172.2 ± 7.4 cm, weight = 68.0 ± 7.3 kg) participated in this study. All subjects performed 4 standardized test batteries consisting of 14 different movements on four separate days. A three-dimensional MMC system (DARI Motion, Lenexa, KS) using 8 cameras surrounding the testing area was used to quantify movement characteristics. 1 × 4 RMANOVAs were used to determine significant differences across days for the composite movement analysis scores, and RM-MANOVAs were used to determine test day differences for the kinematic data (p < 0.05). Intraclass correlation coefficients (ICCs) were reported for all variables to determine test reliability. To determine biological variability, mean absolute differences from previously reported technological variability data were subtracted from the total variability data from the present study. Results: No differences were observed for any composite score (i.e., athleticism, explosiveness, quality, readiness; or any of the 81 kinematic variables. Furthermore, 84 of 85 measured variables exhibited good to excellent ICCs (0.61-0.99). When compared to previously reported technological variability data, 62.3% of item variability was due to biological variability, with 66 of 85 variables exhibiting biological variability as the primary source of error (i.e., >50% total variability). Discussion: Combined, these findings effectively add to the body of literature suggesting sufficient reliability for MMC solutions in capturing kinematic features of human movement.

Socio-economic inequalities and heart failure morbidity and mortality: A systematic review and data synthesis.

Socio-economic status (SES) has been associated with incident and prevalent heart failure (HF), as well as its morbidity and mortality. However, the precise nature of the relationship between SES and HF remains unclear due to inconsistent data. This study aims to provide a comprehensive assessment and data synthesis of the relationship between SES and HF morbidity and mortality. We performed a systematic search and data synthesis using six databases following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Guidelines. The included studies comprised observational studies that reported on HF incidence and prevalence, HF hospitalizations, worsening HF (WHF) and all-cause mortality, as well as treatment options (medical, device and advanced HF therapies). SES was measured on both individual and area levels, encompassing single (e.g., income, education, employment, social risk score, living conditions and housing characteristics) and composite indicators. Among the 4124 studies screened, 79 were included, with an additional 5 identified through cross-referencing. In the majority of studies, a low SES was associated with an increased HF incidence (72%) and prevalence (75%). For mortality, we demonstrated that low SES was associated with increased mortality in 45% of the studies, with 18% of the studies showing mixed results (depending on the indicator, gender or follow-up) and 38% showing non-significant results. Similar patterns were observed for the association between SES, WHF, medical therapy prescriptions and the utilization of devices and advanced HF therapies. There was no clear pattern in the used SES indicators and HF outcomes. This systematic review, using contemporary data, shows that while socio-economic disparity may influence HF incidence, management and subsequent adverse events, these associations are not uniformly predictive. Our review highlights that the impact of SES varies depending on the specific indicators used, reflecting the complexity of its influence on health disparities. Assessment and recognition of SES as an important risk factor can assist clinicians in early detection and customizing HF treatment, while also aiding policymakers in optimizing resource allocation.

Impact of Stenting Long Lesions on Clinical Outcomes in Patients Presenting With Acute Coronary Syndrome and Multivessel Disease: Data From the BIOVASC Trial.

An increased total stent length (TSL) might be associated with a higher risk of clinical events; however, in patients with multivessel disease (MVD), a considerable TSL is often required. In patients presenting with acute coronary syndrome and MVD, immediate complete revascularization was associated with shorter TSL in the BIOVASC Trial. This is a subanalysis of the BIOVASC trial comparing clinical outcomes in patients with either <60 or ≥60 mm TSL. The primary outcome was a composite of all-cause mortality, myocardial infarction, any unplanned ischemia driven revascularization, or cerebrovascular events at 2 years after the index procedure. A total of 1,525 patients were enrolled in the BIOVASC trial, of whom 855 had a TSL of ≥60 mm (long TSL). No significant difference was established when comparing patients treated with either long or short TSL in terms of the primary outcome at 2-year follow-up, which occurred in 117 patients (13.7%) in the ≥60 mm group and 69 patients (10.3%) in the <60 mm group (adjusted hazard ratio 1.25, 95% confidence interval 0.92 to 1.69, p = 0.16). Furthermore, no significant differences were observed in the secondary end points. In conclusion, in patients with acute coronary syndrome and MVD, long stenting did not show a significant difference in clinical event rate compared with short stenting.

Impact and limitations of 3D computational modelling in transcatheter mitral valve replacement-a two-centre Dutch experience.

BACKGROUND: Transcatheter mitral valve replacement (TMVR) has emerged as a minimally invasive alternative to mitral valve surgery for patients at high or prohibitive operative risk. Prospective studies reported favourable outcomes in patients with annulus calcification (valve-in-mitral annulus calcification; ViMAC), failed annuloplasty ring (mitral valve-in-ring; MViR), and bioprosthetic mitral valve dysfunction (mitral valve-in-valve; MViV). Multi-slice computed tomography (MSCT)-derived 3D-modelling and simulations may provide complementary anatomical perspectives for TMVR planning. AIMS: We aimed to illustrate the implementation of MSCT-derived modelling and simulations in the workup of TMVR for ViMAC, MViR, and MViV. METHODS: For this retrospective study, we included all consecutive patients screened for TMVR and compared MSCT data, echocardiographic outcomes and clinical outcomes. RESULTS: Sixteen out of 41 patients were treated with TMVR (ViMAC n = 9, MViR n = 3, MViV n = 4). Eleven patients were excluded for inappropriate sizing, 4 for anchoring issues and 10 for an unacceptable risk of left ventricular outflow tract obstruction (LVOTO) based on 3D modelling. There were 3 procedure-related deaths and 1 non-procedure-related cardiovascular death during 30 days of follow-up. LVOTO occurred in 3 ViMAC patients and 1 MViR patient, due to deeper valve implantation than planned in 3 patients, and anterior mitral leaflet displacement with recurrent basal septum thickening in 1 patient. TMVR significantly reduced mitral mean gradients as compared with baseline measurements (median mean gradient 9.5 (9.0-11.5) mm Hg before TMVR versus 5.0 (4.5-6.0) mm Hg after TMVR, p = 0.03). There was no residual mitral regurgitation at 30 days. CONCLUSION: MSCT-derived 3D modelling and simulation provide valuable anatomical insights for TMVR with transcatheter balloon expandable valves in ViMAC, MViR and MViV. Further planning iterations should target the persistent risk for neo-LVOTO.

The three Plasmodium falciparum Aurora-related kinases display distinct temporal and spatial associations with mitotic structures in asexual blood stage parasites and gametocytes.

Aurora kinases are crucial regulators of mitotic cell cycle progression in eukaryotes. The protozoan malaria parasite Plasmodium falciparum replicates via schizogony, a specialized mode of cell division characterized by consecutive asynchronous rounds of nuclear division by closed mitosis followed by a single cytokinesis event producing dozens of daughter cells. P. falciparum encodes three Aurora-related kinases (PfARKs) that have been reported essential for parasite proliferation, but their roles in regulating schizogony have not yet been explored in great detail. Here, we engineered transgenic parasite lines expressing GFP-tagged PfARK1-3 to provide a systematic analysis of their expression timing and subcellular localization throughout schizogony as well as in the non-dividing gametocyte stages, which are essential for malaria transmission. We demonstrate that all three PfARKs display distinct and highly specific and exclusive spatiotemporal associations with the mitotic machinery. In gametocytes, PfARK3 is undetectable, and PfARK1 and PfARK2 show male-specific expression in late-stage gametocytes, consistent with their requirement for endomitosis during male gametogenesis in the mosquito vector. Our combined data suggest that PfARK1 and PfARK2 have non-overlapping roles in centriolar plaque maturation, assembly of the mitotic spindle, kinetochore-spindle attachment and chromosome segregation, while PfARK3 seems to be exquisitely involved in daughter cell cytoskeleton assembly and cytokinesis. These important new insights provide a reliable foundation for future research aiming at the functional investigation of these divergent and possibly drug-targetable Aurora-related kinases in mitotic cell division of P. falciparum and related apicomplexan parasites.IMPORTANCEMalaria parasites replicate via non-conventional modes of mitotic cell division, such as schizogony, employed by the disease-causing stages in the human blood or endomitosis during male gametogenesis in the mosquito vector. Understanding the molecular mechanisms regulating cell division in these divergent unicellular eukaryotes is not only of scientific interest but also relevant to identify potential new antimalarial drug targets. Here, we carefully examined the subcellular localization of all three Plasmodium falciparum Aurora-related kinases (ARKs), distantly related homologs of Aurora kinases that coordinate mitosis in model eukaryotes. Detailed fluorescence microscopy-based analyses revealed distinct, specific, and exclusive spatial associations for each parasite ARK with different components of the mitotic machinery and at different phases of the cell cycle during schizogony and gametocytogenesis. This comprehensive set of results closes important gaps in our fragmentary knowledge on this important group of kinases and offers a valuable source of information for future functional studies.

The impact of simulated 3x3 tournament on vertical jump force-time metrics in national team male basketball players.

With innovative portable force plate systems being widely implemented for lower-body neuromuscular performance assessment in an applied sports setting and the existing gap in the scientific literature regarding player performance during in-game competitive scenarios, the purpose of the present study was to compare changes in countermovement vertical jump (CVJ) performance pre-post a simulated 3×3 basketball tournament. Seven current or former members of a 3×3 national basketball team volunteered to participate in the present investigation. Upon completing standardized warm-up procedures, athletes stepped on a uni-axial force plate system sampling at 1,000 Hz and performed three maximal-effort CVJs with no arm swing. Then, the athletes proceeded to play a simulated 3×3 basketball tournament composed of two consecutive games, separated by a 15-min rest interval. Immediately following the completion of the second game, the identical CVJ testing procedures were repeated. Paired sample t-tests were used to examine pre-post-tournament differences in nineteen CVJ performance metrics (p < 0.05). The results reveal that force-time metrics during both eccentric and concentric phases of the CVJ remain relatively unchanged pre-post simulated 3×3 basketball tournament. However, multiple force-time metrics within the eccentric phase of the CVJ changed by 12.1%-19.1% (e.g., eccentric peak power and peak velocity, eccentric duration), suggesting that the eccentric phase of CVJ might be responsive to performance stimulus to a greater extent than the concentric phase. Overall, these findings further support the importance of comprehensive CVJ analysis when intending to measure changes in neuromuscular performance.

Moderate Aortic Stenosis-Advanced Imaging, Risk Assessment, and Treatment Strategies.

Moderate aortic stenosis is increasingly recognized as a disease entity with poor prognosis. Diagnosis of moderate aortic stenosis may be complemented by laboratory tests and advanced imaging techniques focused at detecting signs of cardiac damage such as increase of cardiac enzymes (N-terminal pro-B-type Natriuretic Peptide, troponin), left ventricular remodeling (hypertrophy, reduced left ventricular ejection fraction), or myocardial fibrosis. Therapy should include guideline-directed optimal medical therapy for heart failure. Patients with signs of cardiac damage may benefit from early intervention, which is the focus of several ongoing randomized controlled trials. As yet, no evidence-based therapy exists to halt the progression of aortic valve calcification.

High-Throughput Assessment of Bile Salt Export Pump Inhibition Using RapidFire-MS and DESI-MS.

The bile salt export pump (BSEP) assay is widely used to evaluate the potential for drug-induced liver injury (DILI) early in the drug discovery process. While traditional liquid chromatography-mass spectrometry (LC-MS)-based approaches have been utilized for BSEP activity testing, they have intrinsic limitations in either throughput or the requirement for sample preparation and are difficult to scale up in order to screen drug candidates. Here we demonstrate the use of two different high-throughput MS methods based on solid-phase extraction (SPE) and desorption electrospray ionization (DESI) for high-throughput BSEP activity assessment in a label-free manner, with minimal needs for sample workup, at sampling rates of ∼11 and ∼5.5 s/sample, respectively. Both approaches were validated, compared, and successfully applied to the evaluation of 96 drug candidates for the inhibition of taurocholic acid (TCA) transport using BSEP vesicles.

Age-specific sex differences in intravascular ultrasound based coronary atherosclerotic plaque characteristics.

Insights in age- and sex-specific coronary atherosclerotic plaque characteristics may contribute to a better understanding of coronary artery disease and, ultimately, to its prevention and treatment. In 307 women and 406 men aged 20 to 90 years undergoing intravascular ultrasound imaging, sex-based differences in coronary atherosclerotic plaque characteristics were mainly present in younger patients, while these differences were less pronounced at advanced age.

Conduction dynamics over time after transcatheter aortic valve replacement: An expert review.

New conduction disorders remain a frequent complication in current transcatheter aortic valve replacement (TAVR) era. Left bundle branch block (LBBB) occurs early in about 20-30 % of TAVR-patients, persists at 1 month in about 35-45 % of cases and will likely remain thereafter. Third-degree atrioventricular block (AV3B) affects approximately 15 % of patients. Pacemaker dependency gradually decreases throughout follow-up and approximately 25-35 % of patients remain pacemaker dependent at one year. We aimed to review what is currently known about the dynamics of acquired conduction disorders, including extraction of predictors, and how to interpret these dynamics in light of an early discharge policy.

Computed tomography to predict pacemaker need after transcatheter aortic valve replacement.

Transcatheter aortic valve replacement (TAVR) is preferred therapy for elderly patients with severe aortic stenosis (AS) and increasingly used in younger patient populations with good safety and efficacy outcomes. However, cardiac conduction abnormalities remain a frequent complication after TAVR ranging from relative benign interventriculair conduction delays to prognostically relevant left bundle branch block and complete atrio-ventricular (AV) block requiring permanent pacemaker implantation (PPI). Although clinical, procedural and electrocardiographic factors have been identified as predictors of this complication, there is a need for advanced strategies to control the burden of conduction defects particularly as TAVR shifts towards younger populations. This state of the art review highlights the value of ECG-synchronized computed tomographic angiography (CTA) evaluation of the aortic root to better understand and manage conduction problems post-TAVR. An update on CTA derived anatomic features related to conduction issues is provided and complemented with computational framework modelling. This CTA-derived 3-dimensional anatomical reconstruction tool generates patient-specific TAVR simulations enabling operators to adapt procedural strategy and implantation technique to mitigate conduction abnormality risks.

Two KaiABC systems control circadian oscillations in one cyanobacterium.

The circadian clock of cyanobacteria, which predicts daily environmental changes, typically includes a standard oscillator consisting of proteins KaiA, KaiB, and KaiC. However, several cyanobacteria have diverse Kai protein homologs of unclear function. In particular, Synechocystis sp. PCC 6803 harbours, in addition to a canonical kaiABC gene cluster (named kaiAB1C1), two further kaiB and kaiC homologs (kaiB2, kaiB3, kaiC2, kaiC3). Here, we identify a chimeric KaiA homolog, named KaiA3, encoded by a gene located upstream of kaiB3. At the N-terminus, KaiA3 is similar to response-regulator receiver domains, whereas its C-terminal domain resembles that of KaiA. Homology analysis shows that a KaiA3-KaiB3-KaiC3 system exists in several cyanobacteria and other bacteria. Using the Synechocystis sp. PCC 6803 homologs, we observe circadian oscillations in KaiC3 phosphorylation in vitro in the presence of KaiA3 and KaiB3. Mutations of kaiA3 affect KaiC3 phosphorylation, leading to growth defects under both mixotrophic and chemoheterotrophic conditions. KaiC1 and KaiC3 exhibit phase-locked free-running phosphorylation rhythms. Deletion of either system (∆kaiAB1C1 or ∆kaiA3B3C3) alters the period of the cellular backscattering rhythm. Furthermore, both oscillators are required to maintain high-amplitude, self-sustained backscatter oscillations with a period of approximately 24 h, indicating their interconnected nature.

Development and preclinical characterization of a novel radiotheranostic EphA2-targeting bicyclic peptide.

Erythropoietin-producing hepatocellular receptor A2 (EphA2), is a receptor tyrosine kinase involved in cell-cell interactions. It is known to be overexpressed in various tumors and is associated with poor prognosis. EphA2 has been proposed as a target for theranostic applications. Low molecular weight peptide-based scaffolds with low nanomolar affinities have been shown to be ideal in such applications. Bicyclic peptides have emerged as an alternative to traditional peptides for this purpose, offering affinities comparable to antibodies due to their constrained nature, along with high tissue penetration, and improved stability compared to linear counterparts. This study presents the development and comprehensive in vitro and in vivo preclinical evaluation of BCY18469, a novel EphA2-targeting bicyclic peptide-based radiotheranostic agent. Methods: The EphA2-targeting Bicycle® peptide BCY18469 was identified through phage-display and chemically optimized. BCY18469 was radiolabeled with 68Ga, 177Lu and 111In. The physicochemical properties, binding affinity and internalization as well as specificity of the peptide were evaluated in vitro. In vivo PET/MR and SPECT/CT imaging studies were performed using [68Ga]Ga-BCY18469 and [111In]In-BCY18469, respectively, along with biodistribution of [177Lu]Lu-BCY18469 up to 24 h post injection in HT1080- and PC-3-tumor bearing BALB/c nu/nu EphA2-overexpressing xenograft mouse models. Results: The EphA2-targeting bicyclic peptide BCY18469 showed high binding affinity toward human and mouse EphA2 (1.9 and 3.8 nM, respectively). BCY18469 specifically bound and internalized into EphA2-expressing HT1080 cells. Imaging studies showed high tumor enrichment at early time-points (SUV of 1.7 g/mL at 1 h p.i. and 1.2 g/mL at 2 h p.i. in PET/MRI, HT1080 xenograft) with tumor contrast as early as 5 min p.i. and kidney-mediated clearance. Biodistribution studies revealed high early tumor uptake (19.5 ± 3.5 %ID/g at 1 h p.i., HT1080 xenograft) with SPECT/CT imaging further confirming these findings (5.7 ± 1.5 %ID/g at 1 h p.i., PC-3 xenograft). Conclusion: BCY18469 demonstrated high affinity, specific targeting of EphA2, a favorable biodistribution profile, and clearance through renal pathways. These findings underscore the potentially important role of bicyclic peptides in advancing radiotheranostic approaches and encourage additional translational research.

Increased forebrain EAAT3 expression confers resilience to chronic stress.

Depression is a disabling and highly prevalent psychiatric illness. Multiple studies have linked glutamatergic dysfunction with the pathophysiology of depression, but the exact alterations in the glutamatergic system that contribute to depressive-like behaviors are not fully understood. Recent evidence suggests that a decreased level in neuronal glutamate transporter (EAAT3), known to control glutamate levels and limit the activation of glutamate receptors at synaptic sites, may contribute to the manifestation of a depressive phenotype. Here, we tested the possibility that increased EAAT3 expression at excitatory synapses could reduce the susceptibility of mice to develop depressive-like behaviors when challenged to a 5-week unpredictable chronic mild stress (UCMS) protocol. Mice overexpressing EAAT3 in the forebrain (EAAT3glo/CMKII) and control littermates (EAAT3glo) were assessed for depressive-like behaviors and long-term memory performance after being subjected to UCMS conditions. We found that, after UCMS, EAAT3glo/CMKII mice did not exhibit depressive-like behaviors or memory alterations observed in control mice. Moreover, we found that EAAT3glo/CMKII mice did not show alterations in phasic dopamine release in the nucleus accumbens neither in long-term synaptic plasticity in the CA1 region of the hippocampus after UCMS, as observed in control littermates. Altogether these results suggest that forebrain EAAT3 overexpression may be related to a resilient phenotype, both at behavioral and functional level, to the deleterious effect of chronic stress, highlighting the importance of neuronal EAAT3 in the pathophysiology of depressive-like behaviors.