The anti-migratory effects of FKBPL and its peptide derivative, AD-01: regulation of CD44 and the cytoskeletal pathway

Targeting oxidative stress in preeclampsia

Preeclampsia is a complex condition characterized by elevated blood pressure and organ damage involving kidneys or liver, resulting in significant morbidity and mortality for both the mother and the fetus. Increasing evidence suggests that oxidative stress, often caused by mitochondrial dysfunction within fetal trophoblast cells may play a major role in the development and progression of preeclampsia. Oxidative stress occurs as a result of an imbalance between the production of reactive oxygen species (ROS) and the capacity of antioxidant defenses, which can lead to placental cellular damage and endothelial cell dysfunction. Targeting oxidative stress appears to be a promising therapeutic approach that has the potential to improve both short- and long-term maternal and fetal outcomes, thus reducing the global burden of preeclampsia. The purpose of this review is to provide a comprehensive account of the mechanisms of oxidative stress in preeclampsia. Furthermore, it also examines potential interventions for reducing oxidative stress in preeclampsia, including natural antioxidant supplements, lifestyle modifications, mitochondrial targeting antioxidants, and pharmacological agents.A better understanding of the mechanism of action of proposed therapeutic strategies targeting oxidative stress is essential for the identification of companion biomarkers and personalized medicine approaches for the development of effective treatments of preeclampsia.

The FKBPL-based therapeutic peptide, AD-01, protects the endothelium from hypoxia-induced damage by stabilising hypoxia inducible factor-α and inflammation

BACKGROUND

Endothelial dysfunction is a hallmark feature of cardiovascular disease (CVD), yet the underlying mechanisms are still poorly understood. This has impeded the development of effective therapies, particularly for peripheral artery disease. FK506-binding protein like (FKBPL) and its therapeutic peptide mimetic, AD-01, are crucial negative regulators of angiogenesis, however their roles in CVD are unknown. In this study, we aimed to elucidate the FKBPL-mediated mechanisms involved in regulating endothelial dysfunction induced by hypoxia or inflammation, and to determine whether AD-01 can effectively restore endothelial function under these conditions.

METHODS

Hindlimb ischemia was induced in mice by ligating the proximal and distal ends of the right femoral artery, and, after three days, the gastrocnemius muscle was collected for immunofluorescence staining, and RNA extraction. A 3D in vitro microfluidics model was developed to determine the endothelial cell migration and impact of FKBPL following treatments with: (i) 24 µM FKBPL targeted siRNA, (ii) 1 mM hypoxia inducible factor (HIF-1)α activator (DMOG), (iii) 50% (v/v) macrophage conditioned media (MCM), ± 100 nM AD-01. Unbiased, untargeted proteomic analysis was conducted via LC-MS/MS to identify protein targets of AD-01.

RESULTS

FKBPL expression is substantially downregulated in mice after hindlimb ischemia (p < 0.05, protein; p < 0.001, mRNA), correlating with increased neovascularization and altered vascular adhesion molecule expression. In our real-time advanced 3D microfluidics model, hypoxia suppressed FKBPL (p < 0.05) and VE-cadherin (p < 0.001) expression, leading to increased endothelial cell number and migration (p < 0.001), which was restored by AD-01 treatment (p < 0.01). Under inflammatory conditions, FKBPL (p < 0.01) and HIF-1α (p < 0.05) expression was elevated, correlating with increased endothelial cell migration (p < 0.05). Unlike hypoxia, AD-01 did not influence endothelial cell migration under inflammatory conditions, but normalized FKBPL (p < 0.001), HIF-1α (p < 0.05) and CD31 (P < 0.05), expression, in 3D microfluidic cell culture. Proteomic analysis revealed that AD-01 treatment in hypoxia enhanced the abundance of tissue remodelling and vascular integrity proteins including collagen alpha-1(XIX) chain and junctional cadherin associated-5 (JCAD) proteins.

CONCLUSIONS

FKBPL represents an important novel mechanism in hypoxia and inflammation-induced angiogenesis. The FKBPL-based therapeutic peptide, AD-01, could be a viable treatment option for CVD-related endothelial cell dysfunction.

MRI radiomics based on machine learning in high-grade gliomas as a promising tool for prediction of CD44 expression and overall survival

We aimed to predict CD44 expression and assess its prognostic significance in patients with high-grade gliomas (HGG) using non-invasive radiomics models based on machine learning. Enhanced magnetic resonance imaging, along with the corresponding gene expression and clinicopathological data, was downloaded from online database. Kaplan-Meier survival curves, univariate and multivariate COX analyses, and time-dependent receiver operating characteristic were used to assess the prognostic value of CD44. Following the screening of radiomic features using repeat least absolute shrinkage and selection operator, two radiomics models were constructed utilizing logistic regression and support vector machine for validation purposes. The results indicated that CD44 protein levels were higher in HGG compared to normal brain tissues, and CD44 expression emerged as an independent biomarker of diminished overall survival (OS) in patients with HGG. Moreover, two predictive models based on seven radiomic features were built to predict CD44 expression levels in HGG, achieving areas under the curves (AUC) of 0.809 and 0.806, respectively. Calibration and decision curve analysis validated the fitness of the models. Notably, patients with high radiomic scores presented worse OS (p < 0.001). In summary, our results indicated that the radiomics models effectively differentiate CD44 expression level and OS in patients with HGG.

Evaluating oxidative stress targeting treatments in in vitro models of placental stress relevant to preeclampsia

Background

Preeclampsia is a complex pregnancy disorder characterized by the new onset of hypertension and organ dysfunction, often leading to significant maternal and fetal morbidity and mortality. Placental dysfunction is a hallmark feature of preeclampsia, which is often caused by inappropriate trophoblast cell function in association with oxidative stress, inflammation and/or pathological hypoxia. This study explores the role of oxidative stress in trophoblast cell-based models mimicking the preeclamptic placenta and evaluates potential therapeutic strategies targeting these mechanisms.

Methods

Uric acid (UA) and malondialdehyde (MDA) concentrations were measured in human plasma from women with preeclampsia (n = 24) or normotensive controls (n = 14) using colorimetric assays. Custom-made first trimester trophoblast cell line, ACH-3P, was exposed to various preeclampsia-like stimuli including hypoxia mimetic (dimethyloxalylglycine or DMOG, 1 mM), inflammation (tumour necrosis factor or TNF-α, 10 ng/mL) or mitochondria dysfunction agent, (Rhodamine-6G or Rho-6G, 1 μg/mL), ± aspirin (0.5 mM), metformin (0.5 mM), AD-01 (100 nM) or resveratrol (15 µM), for 48 h. Following treatments, UA/MDA, proliferation (MTT), wound scratch and cytometric bead, assays, were performed.

Results

Overall, MDA plasma concentration was increased in the preeclampsia group compared to healthy controls (p < 0.001) whereas UA showed a trend towards an increase (p = 0.06); when adjusted for differences in gestational age at blood sampling, MDA remained (p < 0.001) whereas UA became (p = 0.03) significantly correlated with preeclampsia. Our 2D first trimester trophoblast cell-based in vitro model of placental stress as observed in preeclampsia, mimicked the increase in UA concentration following treatment with DMOG (p < 0.0001), TNF-α (p < 0.05) or Rho-6G (p < 0.001) whereas MDA cell concentration increased only in the presence of DMOG (p < 0.0001) or Rho-6G (p < 0.001). Metformin was able to abrogate DMOG- (p < 0.01), Rho-6G- (p < 0.0001) or TNF-α- (p < 0.01) induced increase in UA, or DMOG- (p < 0.0001) or TNF-α- (p < 0.05)induced increase in MDA. AD-01 abrogated UA or MDA increase in the presence of TNF-α (p < 0.001) or Rho-6G (p < 0.001)/DMOG (p < 0.0001), respectively. The preeclampsia-like stimuli also mimicked adverse impact on trophoblast cell proliferation, migration and inflammation, most of which were restored with either aspirin, metformin, resveratrol, or AD-01 (p < 0.05).

Conclusion

Our 2D in vitro models recapitulate the response of the first trimester trophoblast cells to preeclampsia-like stresses, modelling inappropriate placental development, and demonstrate therapeutic potential of repurposed treatments.

Resolving the current controversy of use and reuse of housekeeping proteins in ageing research: Focus on saving people's tax dollars

The use of housekeeping genes and proteins to normalize mRNA and protein levels in biomedical research has faced growing scrutiny. Researchers encounter challenges in determining the optimal frequency for running housekeeping proteins such as β-actin, Tubulin, and GAPDH for nuclear-encoded proteins, and Porin, HSP60, and TOM20 for mitochondrial proteins alongside experimental proteins. The regulation of these proteins varies with age, gender, disease progression, epitope nature, gel running conditions, and their reported sizes can differ among antibody suppliers. Additionally, anonymous readers have raised concerns about peer-reviewed and published articles, creating confusion and concern within the research and academic institutions. To clarify these matters, this minireview discusses the role of reference housekeeping proteins in Western blot analysis and outlines key considerations for their use as normalization controls. Instead of Western blotting of housekeeping proteins, staining of total proteins, using Amido Black and Coomassie Blue can be visualized the total protein content on a membrane. The reducing repeated Western blotting analysis of housekeeping proteins, will save resources, time and efforts and in turn increase the number of competitive grants from NIH and funding agencies. We also discussed the use of dot blots over traditional Western blots, when protein levels are low in rare tissues/specimens and cell lines. We sincerely hope that the facts, figures, and discussions presented in this article will clarify the current controversy regarding housekeeping protein(s) use, reuse, and functional aspects of housekeeping proteins. The contents presented in our article will be useful to students, scholars and researchers of all levels in cell biology, protein chemistry and mitochondrial research.

Hsa_circ_0001402 alleviates vascular neointimal hyperplasia through a miR-183-5p-dependent regulation of vascular smooth muscle cell proliferation, migration, and autophagy

INTRODUCTION

Vascular neointimal hyperplasia, a pathological process observed in cardiovascular diseases such as atherosclerosis and pulmonary hypertension, involves the abundant presence of vascular smooth muscle cells (VSMCs). The proliferation, migration, and autophagy of VSMCs are associated with the development of neointimal lesions. Circular RNAs (circRNAs) play critical roles in regulating VSMC proliferation and migration, thereby participating in neointimal hyperplasia. However, the regulatory roles of circRNAs in VSMC autophagy remain unclear.

OBJECTIVES

We aimed to identify circRNAs that are involved in VSMC autophagy-mediated neointimal hyperplasia, as well as elucidate the underlying mechanisms.

METHODS

Dual-luciferase reporter gene assay was performed to validate two competing endogenous RNA axes, hsa_circ_0001402/miR-183-5p/FKBP prolyl isomerase like (FKBPL) and hsa_circ_0001402/miR-183-5p/beclin 1 (BECN1). Cell proliferation and migration analyses were employed to investigate the effects of hsa_circ_0001402, miR-183-5p, or FKBPL on VSMC proliferation and migration. Cell autophagy analysis was conducted to reveal the role of hsa_circ_0001402 or miR-183-5p on VSMC autophagy. The role of hsa_circ_0001402 or miR-183-5p on neointimal hyperplasia was evaluated using a mouse model of common carotid artery ligation.

RESULTS

Hsa_circ_0001402 acted as a sponge for miR-183-5p, leading to the suppression of miR-183-5p expression. Through direct interaction with the coding sequence (CDS) of FKBPL, miR-183-5p promoted VSMC proliferation and migration by decreasing FKBPL levels. Besides, miR-183-5p reduced BECN1 levels by targeting the 3'-untranslated region (UTR) of BECN1, thus inhibiting VSMC autophagy. By acting as a miR-183-5p sponge, overexpression of hsa_circ_0001402 increased FKBPL levels to inhibit VSMC proliferation and migration, while simultaneously elevating BECN1 levels to activate VSMC autophagy, thereby alleviating neointimal hyperplasia.

CONCLUSION

Hsa_circ_0001402, acting as a miR-183-5p sponge, increases FKBPL levels to inhibit VSMC proliferation and migration, while enhancing BECN1 levels to activate VSMC autophagy, thus alleviating neointimal hyperplasia. The hsa_circ_0001402/miR-183-5p/FKBPL axis and hsa_circ_0001402/miR-183-5p/BECN1 axis may offer potential therapeutic targets for neointimal hyperplasia.

Quantitative Point of Care Tests for Timely Diagnosis of Early-Onset Preeclampsia with High Sensitivity and Specificity

Preeclampsia is a heterogeneous and multiorgan cardiovascular disorder of pregnancy. Here, we report the development of a novel strip-based lateral flow assay (LFA) using lanthanide-doped upconversion nanoparticles conjugated to antibodies targeting two different biomarkers for detection of preeclampsia. We first measured circulating plasma FKBPL and CD44 protein concentrations from individuals with early-onset preeclampsia (EOPE), using ELISA. We confirmed that the CD44/FKBPL ratio is reduced in EOPE with a good diagnostic potential. Using our rapid LFA prototypes, we achieved an improved lower limit of detection: 10 pg ml-1 for FKBPL and 15 pg ml-1 for CD44, which is more than one order lower than the standard ELISA method. Using clinical samples, a cut-off value of 1.24 for CD44/FKBPL ratio provided positive predictive value of 100 % and the negative predictive value of 91 %. Our LFA shows promise as a rapid and highly sensitive point-of-care test for preeclampsia.

Association of Vascular Endothelial Growth Factors (VEGFs) with Recurrent Miscarriage: A Systematic Review of the Literature

Recurrent miscarriage (RM) can be defined as two or more consecutive miscarriages before 20 weeks' gestation. Vascular endothelial growth factors (VEGFs) play an important role in endometrial angiogenesis and decidualization, prerequisites for successful pregnancy outcomes. We conducted a systematic review of the published literature investigating the role of VEGFs in RM. In particular, we explored the methodological inconsistencies between the published reports on this topic. To our knowledge, this is the first systematic literature review to examine the role of VEGFs in RM. Our systematic search followed PRISMA guidelines. Three databases, Medline (Ovid), PubMed, and Embase, were searched. Assessment-bias analyses were conducted using the Joanna Bigger Institute critical appraisal method for case-control studies. Thirteen papers were included in the final analyses. These studies included 677 cases with RM and 724 controls. Endometrial levels of VEGFs were consistently lower in RM cases compared to controls. There were no consistent significant findings with respect to VEGFs levels in decidua, fetoplacental tissues, and serum when RM cases were compared to controls. The interpretation of studies that explored the relationship between VEGFs and RM is hampered by inconsistencies in defining clinical, sampling, and analytical variables. To clarify the association between VEGF and RM in future studies, researchers ideally should use similarly defined clinical groups, similar samples collected in the same way, and laboratory analyses undertaken using the same methods.

FK506-Binding Protein like (FKBPL) Has an Important Role in Heart Failure with Preserved Ejection Fraction Pathogenesis with Potential Diagnostic Utility

Heart failure (HF) is the leading cause of hospitalisations worldwide, with only 35% of patients surviving the first 5 years after diagnosis. The pathogenesis of HF with preserved ejection fraction (HFpEF) is still unclear, impeding the implementation of effective treatments. FK506-binding protein like (FKBPL) and its therapeutic peptide mimetic, AD-01, are critical mediators of angiogenesis and inflammation. Thus, in this study, we investigated-for the first time-FKBPL's role in the pathogenesis and as a biomarker of HFpEF. In vitro models of cardiac hypertrophy following exposure to a hypertensive stimulus, angiotensin-II (Ang-II, 100 nM), and/or AD-01 (100 nM), for 24 and 48 h were employed as well as human plasma samples from people with different forms of HFpEF and controls. Whilst the FKBPL peptide mimetic, AD-01, induced cardiomyocyte hypertrophy in a similar manner to Ang-II (p < 0.0001), when AD-01 and Ang-II were combined together, this process was abrogated (p < 0.01-0.0001). This mechanism appears to involve a negative feedback loop related to FKBPL (p < 0.05). In human plasma samples, FKBPL concentration was increased in HFpEF compared to controls (p < 0.01); however, similar to NT-proBNP and Gal-3, it was unable to stratify between different forms of HFpEF: acute HFpEF, chronic HFpEF and hypertrophic cardiomyopathy (HCM). FKBPL may be explored for its biomarker and therapeutic target potential in HFpEF.

A placenta-on-a-chip model to determine the regulation of FKBPL and galectin-3 in preeclampsia

Preeclampsia is a pregnancy-specific cardiovascular disorder, involving significant maternal endothelial dysfunction. Although inappropriate placentation due to aberrant angiogenesis, inflammation and shallow trophoblast invasion are the root causes of preeclampsia, pathogenic mechanisms are poorly understood, particularly in early pregnancy. Here, we first confirm the abnormal expression of important vascular and inflammatory proteins, FK506-binding protein-like (FKBPL) and galectin-3 (Gal-3), in human plasma and placental tissues from women with preeclampsia and normotensive controls. We then employ a three-dimensional microfluidic placental model incorporating human umbilical vein endothelial cells (HUVECs) and a first trimester trophoblast cell line (ACH-3P) to investigate FKBPL and Gal-3 signaling in inflammatory conditions. In human samples, both circulating (n = 17 controls; n = 30 preeclampsia) and placental (n ≥ 6) FKBPL and Gal-3 levels were increased in preeclampsia compared to controls (plasma: FKBPL, p < 0.0001; Gal-3, p < 0.01; placenta: FKBPL, p < 0.05; Gal-3, p < 0.01), indicative of vascular dysfunction in preeclampsia. In our placenta-on-a-chip model, we show that endothelial cells are critical for trophoblast-mediated migration and that trophoblasts effectively remodel endothelial vascular networks. Inflammatory cytokine tumour necrosis factor-α (10 ng/mL) modulates both FKBPL and Gal-3 signaling in conjunction with trophoblast migration and impairs vascular network formation (p < 0.005). Our placenta-on-a-chip recapitulates aspects of inappropriate placental development and vascular dysfunction in preeclampsia.

Functions of the Hsp90-Binding FKBP Immunophilins

The Hsp90 chaperone is known to interact with a diverse array of client proteins. However, in every case examined, Hsp90 is also accompanied by a single or several co-chaperone proteins. One class of co-chaperone contains a tetratricopeptide repeat (TPR) domain that targets the co-chaperone to the C-terminal region of Hsp90. Within this class are Hsp90-binding peptidylprolyl isomerases, most of which belong to the FK506-binding protein (FKBP) family. Despite the common association of FKBP co-chaperones with Hsp90, it is abundantly clear that the client protein influences, and is often influenced by, the particular FKBP bound to Hsp90. Examples include Xap2 in aryl hydrocarbon receptor complexes and FKBP52 in steroid receptor complexes. In this chapter, we discuss the known functional roles played by FKBP co-chaperones and, where possible, relate distinctive functions to structural differences between FKBP members.

A first-in-human Phase I dose-escalation trial of the novel therapeutic peptide, ALM201, demonstrates a favourable safety profile in unselected patients with ovarian cancer and other advanced solid tumours

Background

We aimed to assess the safety, tolerability and pharmacokinetics of a novel anti-angiogenic peptide.

Methods

We used an open-label, multicentre, dose-escalation Phase I trial design in patients with solid tumours. ALM201 was administered subcutaneously once daily for 5 days every week in unselected patients with solid tumours.

Results

Twenty (8 male, 12 female) patients with various solid tumours were treated (18 evaluable for toxicity) over eight planned dose levels (10–300 mg). ALM201 was well-tolerated at all dose levels without CTCAE grade 4 toxicities. Adverse events were predominantly grades 1–2, most commonly, localised injection-site reactions (44.4%), vomiting (11%), fatigue (16.7%), arthralgia (5.6%) and headache (11%). Thrombosis occurred in two patients at the 100 mg and 10 mg dose levels. The MTD was not reached, and a recommended Phase II dose (RP2D) based on feasibility was declared. Plasma exposure increased with dose (less than dose-proportional at the two highest dose levels). No peptide accumulation was evident. The median treatment duration was 11.1 (range 3–18) weeks. Four of 18 evaluable patients (22%) had stable disease.

Conclusions

Doses up to 300 mg of ALM201 subcutaneously are feasible and well-tolerated. Further investigation of this agent in selected tumour types/settings would benefit from patient-selection biomarkers.

Characterisation of cardiac health in the reduced uterine perfusion pressure model and a 3D cardiac spheroid model, of preeclampsia

Background

Preeclampsia is a dangerous cardiovascular disorder of pregnancy that leads to an increased risk of future cardiovascular and metabolic disorders. Much of the pathogenesis and mechanisms involved in cardiac health in preeclampsia are unknown. A novel anti-angiogenic protein, FKBPL, is emerging as having a potential role in both preeclampsia and cardiovascular disease (CVD). Therefore, in this study we aimed to characterise cardiac health and FKBPL regulation in the rat reduced uterine perfusion pressure (RUPP) and a 3D cardiac spheroid model of preeclampsia.

Methods

The RUPP model was induced in pregnant rats and histological analysis performed on the heart, kidney, liver and placenta (n ≥ 6). Picrosirius red staining was performed to quantify collagen I and III deposition in rat hearts, placentae and livers as an indicator of fibrosis. RT-qPCR was used to determine changes in Fkbpl, Icam1, Vcam1, Flt1 and Vegfa mRNA in hearts and/or placentae and ELISA to evaluate cardiac brain natriuretic peptide (BNP45) and FKBPL secretion. Immunofluorescent staining was also conducted to analyse the expression of cardiac FKBPL. Cardiac spheroids were generated using human cardiac fibroblasts and human coronary artery endothelial cells and treated with patient plasma from normotensive controls, early-onset preeclampsia (EOPE) and late-onset preeclampsia (LOPE); n = 3. FKBPL and CD31 expression was quantified by immunofluorescent labelling.

Results

The RUPP procedure induced significant increases in blood pressure (p < 0.001), collagen deposition (p < 0.001) and cardiac BNP45 (p < 0.05). It also induced a significant increase in cardiac FKBPL mRNA (p < 0.05) and protein  expression  (p < 0.01). RUPP placentae also exhibited increased collagen deposition and decreased Flt1 mRNA expression (p < 0.05). RUPP kidneys revealed an increase in average glomerular size (p < 0.05). Cardiac spheroids showed a significant increase in FKBPL expression when treated with LOPE plasma (p < 0.05) and a trend towards increased FKBPL expression following treatment with EOPE plasma (p = 0.06).

Conclusions

The rat RUPP model induced cardiac, renal and placental features reflective of preeclampsia. FKBPL was increased in the hearts of RUPP rats and cardiac spheroids treated with plasma from women with preeclampsia, perhaps reflective of restricted angiogenesis and inflammation in this disorder. Elucidation of these novel FKBPL mechanisms in cardiac health in preeclampsia could be key in preventing future CVD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13293-021-00376-1.

Role of A Novel Angiogenesis FKBPL-CD44 Pathway in Preeclampsia Risk Stratification and Mesenchymal Stem Cell Treatment

CONTEXT

Preeclampsia is a leading cardiovascular complication in pregnancy lacking effective diagnostic and treatment strategies.

OBJECTIVE

To investigate the diagnostic and therapeutic target potential of the angiogenesis proteins, FK506-binding protein like (FKBPL) and CD44.

DESIGN AND INTERVENTION

FKBPL and CD44 plasma concentration or placental expression were determined in women pre- or postdiagnosis of preeclampsia. Trophoblast and endothelial cell function was assessed following mesenchymal stem cell (MSC) treatment and in the context of FKBPL signaling.

SETTINGS AND PARTICIPANTS

Human samples prediagnosis (15 and 20 weeks of gestation; n ≥ 57), or postdiagnosis (n = 18 for plasma; n = 4 for placenta) of preeclampsia were used to determine FKBPL and CD44 levels, compared to healthy controls. Trophoblast or endothelial cells were exposed to low/high oxygen, and treated with MSC-conditioned media (MSC-CM) or a FKBPL overexpression plasmid.

MAIN OUTCOME MEASURES

Preeclampsia risk stratification and diagnostic potential of FKBPL and CD44 were investigated. MSC treatment effects and FKBPL-CD44 signaling in trophoblast and endothelial cells were assessed.

RESULTS

The CD44/FKBPL ratio was reduced in placenta and plasma following clinical diagnosis of preeclampsia. At 20 weeks of gestation, a high plasma CD44/FKBPL ratio was independently associated with the 2.3-fold increased risk of preeclampsia (odds ratio = 2.3, 95% confidence interval [CI] 1.03-5.23, P = 0.04). In combination with high mean arterial blood pressure (>82.5 mmHg), the risk further increased to 3.9-fold (95% CI 1.30-11.84, P = 0.016). Both hypoxia and MSC-based therapy inhibited FKBPL-CD44 signaling, enhancing cell angiogenesis.

CONCLUSIONS

The FKBPL-CD44 pathway appears to have a central role in the pathogenesis of preeclampsia, showing promising utilities for early diagnostic and therapeutic purposes.

FKBPL and SIRT-1 Are Downregulated by Diabetes in Pregnancy Impacting on Angiogenesis and Endothelial Function

Diabetes in pregnancy is associated with adverse pregnancy outcomes including preterm birth. Although the mechanisms leading to these pregnancy complications are still poorly understood, aberrant angiogenesis and endothelial dysfunction play a key role. FKBPL and SIRT-1 are critical regulators of angiogenesis, however, their roles in pregnancies affected by diabetes have not been examined before in detail. Hence, this study aimed to investigate the role of FKBPL and SIRT-1 in pre-gestational (type 1 diabetes mellitus, T1D) and gestational diabetes mellitus (GDM). Placental protein expression of important angiogenesis proteins, FKBPL, SIRT-1, PlGF and VEGF-R1, was determined from pregnant women with GDM or T1D, and in the first trimester trophoblast cells exposed to high glucose (25 mM) and varying oxygen concentrations [21%, 6.5%, 2.5% (ACH-3Ps)]. Endothelial cell function was assessed in high glucose conditions (30 mM) and following FKBPL overexpression. Placental FKBPL protein expression was downregulated in T1D (FKBPL; p<0.05) whereas PlGF/VEGF-R1 were upregulated (p<0.05); correlations adjusted for gestational age were also significant. In the presence of GDM, only SIRT-1 was significantly downregulated (p<0.05) even when adjusted for gestational age (r=-0.92, p=0.001). Both FKBPL and SIRT-1 protein expression was reduced in ACH-3P cells in high glucose conditions associated with 6.5%/2.5% oxygen concentrations compared to experimental normoxia (21%; p<0.05). FKBPL overexpression in endothelial cells (HUVECs) exacerbated reduction in tubule formation compared to empty vector control, in high glucose conditions (junctions; p<0.01, branches; p<0.05). In conclusion, FKBPL and/or SIRT-1 downregulation in response to diabetic pregnancies may have a key role in the development of vascular dysfunction and associated complications affected by impaired placental angiogenesis.

FKBPL is associated with metabolic parameters and is a novel determinant of cardiovascular disease

Type 2 diabetes (T2D) is associated with increased risk of cardiovascular disease (CVD). As disturbed angiogenesis and endothelial dysfunction are strongly implicated in T2D and CVD, we aimed to investigate the association between a novel anti-angiogenic protein, FK506-binding protein like (FKBPL), and these diseases. Plasma FKBPL was quantified by ELISA cross-sectionally in 353 adults, consisting of 234 T2D and 119 non-diabetic subjects with/without CVD, matched for age, BMI and gender. FKBPL levels were higher in T2D (adjusted mean: 2.03 ng/ml ± 0.90 SD) vs. non-diabetic subjects (adjusted mean: 1.79 ng/ml ± 0.89 SD, p = 0.02), but only after adjustment for CVD status. In T2D, FKBPL was negatively correlated with fasting blood glucose, HbA1c and diastolic blood pressure (DBP), and positively correlated with age, known diabetes duration, waist/hip ratio, urinary albumin/creatinine ratio (ACR) and fasting C-peptide. FKBPL plasma concentrations were increased in the presence of CVD, but only in the non-diabetic group (CVD: 2.02 ng/ml ± 0.75 SD vs. no CVD: 1.68 ng/ml ± 0.79 SD, p = 0.02). In non-diabetic subjects, FKBPL was positively correlated with an established biomarker for CVD, B-type Natriuretic Peptide (BNP), and echocardiographic parameters of diastolic dysfunction. FKBPL was a determinant of CVD in the non-diabetic group in addition to age, gender, total-cholesterol and systolic blood pressure (SBP). FKBPL may be a useful anti-angiogenic biomarker in CVD in the absence of diabetes and could represent a novel CVD mechanism.

FKBPL-based peptide, ALM201, targets angiogenesis and cancer stem cells in ovarian cancer

Background

ALM201 is a therapeutic peptide derived from FKBPL that has previously undergone preclinical and clinical development for oncology indications and has completed a Phase 1a clinical trial in ovarian cancer patients and other advanced solid tumours.

Methods

In vitro, cancer stem cell (CSC) assays in a range of HGSOC cell lines and patient samples, and in vivo tumour initiation, growth delay and limiting dilution assays, were utilised. Mechanisms were determined by using immunohistochemistry, ELISA, qRT-PCR, RNAseq and western blotting. Endogenous FKBPL protein levels were evaluated using tissue microarrays (TMA).

Results

ALM201 reduced CSCs in cell lines and primary samples by inducing differentiation. ALM201 treatment of highly vascularised Kuramochi xenografts resulted in tumour growth delay by disruption of angiogenesis and a ten-fold decrease in the CSC population. In contrast, ALM201 failed to elicit a strong antitumour response in non-vascularised OVCAR3 xenografts, due to high levels of IL-6 and vasculogenic mimicry. High endogenous tumour expression of FKBPL was associated with an increased progression-free interval, supporting the protective role of FKBPL in HGSOC.

Conclusion

FKBPL-based therapy can (i) dually target angiogenesis and CSCs, (ii) target the CD44/STAT3 pathway in tumours and (iii) is effective in highly vascularised HGSOC tumours with low levels of IL-6.

A Three-Dimensional In Vitro Coculture Model to Quantify Breast Epithelial Cell Adhesion to Endothelial Cells

Three-dimensional (3D) in vitro culture models better recapitulate the tissue microenvironment, and therefore may provide a better platform to evaluate therapeutic effects on adhesive cell-cell interactions. The objective of this study was to determine if AD-01, a peptide derivative of FK506-binding protein like that is reported to bind to the adhesion receptor CD44, would induce a greater reduction in breast epithelial spheroid adhesion to endothelial tube-like networks in our 3D coculture model system compared to two-dimensional (2D) culture. MCF10A, MCF10A-NeuN, MDA-MB-231, and MCF7 breast epithelial cells were pretreated with AD-01 either as single cells or as spheroids. Breast epithelial cell adhesion to 2D tissue culture substrates was first measured, followed by spheroid formation (breast cell-cell adhesion) and spheroid adhesion to Matrigel or endothelial networks. Finally, CD44 expression was quantified in breast epithelial cells in 2D and 3D culture. Our results show that AD-01 had the largest effect on spheroid formation, specifically in breast cancer cell lines. AD-01 also inhibited breast cancer spheroid adhesion to and migration along endothelial networks. The different breast epithelial cell lines expressed more CD44 when cultured as 3D spheroids, but this did not universally translate into higher protein levels. This study shows that 3D coculture models can enable unique insights into cell adhesion, migration, and cell-cell interactions, thereby enhancing understanding of basic biological mechanisms. Furthermore, such 3D coculture systems may also represent a more relevant testing platform for understanding the mechanism-of-action of new therapeutic agents. Impact Statement Cell adhesion is inherently different in two dimensional (2D) compared to three dimensional (3D) culture; yet, most adhesion assays in academia and industry are still conducted in 2D because few simple, yet effective, adhesion models exist in 3D. Recently we developed a 3D in vitro coculture model to examine breast epithelial spheroid interactions with endothelial tubes. We now show that this 3D coculture model can effectively be used to interrogate and quantify drug-induced differences in breast epithelial cell adhesion that are unique to 3D cocultures. This 3D coculture adhesion model can furthermore be modified for use with other cell types to better predict drug effects on cell-vasculature adhesion.

FKBPL and its peptide derivatives inhibit endocrine therapy resistant cancer stem cells and breast cancer metastasis by downregulating DLL4 and Notch4

BACKGROUND

Optimising breast cancer treatment remains a challenge. Resistance to therapy is a major problem in both ER- and ER+ breast cancer. Tumour recurrence after chemotherapy and/or targeted therapy leads to more aggressive tumours with enhanced metastatic ability. Self-renewing cancer stem cells (CSCs) have been implicated in treatment resistance, recurrence and the development of metastatic disease.

METHODS

In this study, we utilised in vitro, in vivo and ex vivo breast cancer models using ER+ MCF-7 and ER- MDA-MB-231 cells, as well as solid and metastatic breast cancer patient samples, to interrogate the effects of FKBPL and its peptide therapeutics on metastasis, endocrine therapy resistant CSCs and DLL4 and Notch4 expression. The effects of FKBPL overexpression or peptide treatment were assessed using a t-test or one-way ANOVA with Dunnett's multiple comparison test.

RESULTS

We demonstrated that FKBPL overexpression or treatment with FKBPL-based therapeutics (AD-01, pre-clinical peptide /ALM201, clinical peptide) inhibit i) CSCs in both ER+ and ER- breast cancer, ii) cancer metastasis in a triple negative breast cancer metastasis model and iii) endocrine therapy resistant CSCs in ER+ breast cancer, via modulation of the DLL4 and Notch4 protein and/or mRNA expression. AD-01 was effective at reducing triple negative MDA-MB-231 breast cancer cell migration (n ≥ 3, p < 0.05) and invasion (n ≥ 3, p < 0.001) and this was translated in vivo where AD-01 inhibited breast cancer metastasis in MDA-MB-231-lucD3H1 in vivo model (p < 0.05). In ER+ MCF-7 cells and primary breast tumour samples, we demonstrated that ALM201 inhibits endocrine therapy resistant mammospheres, representative of CSC content (n ≥ 3, p < 0.05). Whilst an in vivo limiting dilution assay, using SCID mice, demonstrated that ALM201 alone or in combination with tamoxifen was very effective at delaying tumour recurrence by 12 (p < 0.05) or 21 days (p < 0.001), respectively, by reducing the number of CSCs. The potential mechanism of action, in addition to CD44, involves downregulation of DLL4 and Notch4.

CONCLUSION

This study demonstrates, for the first time, the pre-clinical activity of novel systemic anti-cancer therapeutic peptides, ALM201 and AD-01, in the metastatic setting, and highlights their impact on endocrine therapy resistant CSCs; both areas of unmet clinical need.

Targeting cancer stem cells in the clinic: Current status and perspectives

Resistance to chemotherapy and cancer relapse are major clinical challenges attributed to a sub population of cancer stem cells (CSCs). The concept of CSCs has been the subject of intense research by the oncology community since evidence for their existence was first published over twenty years ago. Emerging data indicates that they are also able to evade novel therapies such as targeted agents, immunotherapies and anti-angiogenics. The inability to appropriately identify and isolate CSCs is a major hindrance to the field and novel technologies are now being utilized. Agents that target CSC-associated cell surface receptors and signaling pathways have generated promising pre-clinical results and are now entering clinical trial. Here we discuss and evaluate current therapeutic strategies to target CSCs.

Comparison of the adolescent and adult mouse prefrontal cortex proteome

Adolescence is a developmental period characterized by unique behavioral phenotypes (increased novelty seeking, risk taking, sociability and impulsivity) and increased risk for destructive behaviors, impaired decision making and psychiatric illness. Adaptive and maladaptive adolescent traits have been associated with development of the medial prefrontal cortex (mPFC), a brain region that mediates regulatory control of behavior. However, the molecular changes that underlie brain development and behavioral vulnerability have not been fully characterized. Using high-throughput 2D DIGE spot profiling with identification by MALDI-TOF mass spectrometry, we identified 62 spots in the PFC that exhibited age-dependent differences in expression. Identified proteins were associated with diverse cellular functions, including intracellular signaling, synaptic plasticity, cellular organization and metabolism. Separate Western blot analyses confirmed age-related changes in DPYSL2, DNM1, STXBP1 and CFL1 in the mPFC and expanded these findings to the dorsal striatum, nucleus accumbens, motor cortex, amygdala and ventral tegmental area. Ingenuity Pathway Analysis (IPA) identified functional interaction networks enriched with proteins identified in the proteomics screen, linking age-related alterations in protein expression to cellular assembly and development, cell signaling and behavior, and psychiatric illness. These results provide insight into potential molecular components of adolescent cortical development, implicating structural processes that begin during embryonic development as well as plastic adaptations in signaling that may work in concert to bring the cortex, and other brain regions, into maturity.

FKBPL: a marker of good prognosis in breast cancer

FK506-binding protein-like (FKBPL) has established roles as an anti-tumor protein, with a therapeutic peptide based on this protein, ALM201, shortly entering phase I/II clinical trials. Here, we evaluated FKBPL's prognostic ability in primary breast cancer tissue, represented on tissue microarrays (TMA) from 3277 women recruited into five independent retrospective studies, using immunohistochemistry (IHC). In a meta-analysis, FKBPL levels were a significant predictor of BCSS; low FKBPL levels indicated poorer breast cancer specific survival (BCSS) (hazard ratio (HR) = 1.30, 95% confidence interval (CI) 1.14–1.49, p < 0.001). The prognostic impact of FKBPL remained significant after adjusting for other known prognostic factors (HR = 1.25, 95% CI 1.07–1.45, p = 0.004). For the sub-groups of 2365 estrogen receptor (ER) positive patients and 1649 tamoxifen treated patients, FKBPL was significantly associated with BCSS (HR = 1.34, 95% CI 1.13–1.58, p < 0.001, and HR = 1.25, 95% CI 1.04–1.49, p = 0.02, respectively). A univariate analysis revealed that FKBPL was also a significant predictor of relapse free interval (RFI) within the ER positive patient group, but it was only borderline significant within the smaller tamoxifen treated patient group (HR = 1.32 95% CI 1.05–1.65, p = 0.02 and HR = 1.23 95% CI 0.99–1.54, p = 0.06, respectively). The data suggests a role for FKBPL as a prognostic factor for BCSS, with the potential to be routinely evaluated within the clinic.

RALA-mediated delivery of FKBPL nucleic acid therapeutics

AIMS

RALA is a novel 30 mer bioinspired amphipathic peptide that is showing promise for gene delivery. Here, we used RALA to deliver the FK506-binding protein like - FKBPL gene (pFKBPL) - a novel member of the immunophilin protein family. FKBPL is a secreted protein, with overexpression shown to inhibit angiogenesis, tumor growth and stemness, through a variety of intra- and extracellular signaling mechanisms. We also elucidated proangiogenic activity and stemness after utilizing RALA to deliver siRNA (siFKBPL).

MATERIALS & METHODS

The RALA/pFKBPL and RALA/siFKBPL nanoparticles were characterized in terms of size, charge, stability and toxicity. Overexpression and knockdown of FKBPL was assessed in vitro and in vivo.

RESULTS

RALA delivered both pFKBPL and siFKBPL with less cytotoxicity than commercially available counterparts. In vivo, RALA/pFKBPL delivery retarded tumor growth, and prolonged survival with an associated decrease in angiogenesis, while RALA/siFKBPL had no effect on tumor growth rate or survival, but resulted in an increase in angiogenesis and stemness.

CONCLUSION

RALA is an effective delivery system for both FKBPL DNA and RNAi and highlights an alternative therapeutic approach to harnessing FKBPL's antiangiogenic and antistemness activity.

RhoA/mDia-1/profilin-1 signaling targets microvascular endothelial dysfunction in diabetic retinopathy

BACKGROUND

Diabetic retinopathy (DR) is a major cause of blindness in the working-age populations of developed countries, and effective treatments and prevention measures have long been the foci of study. Patients with DR invariably demonstrate impairments of the retinal microvascular endothelium. Many observational and preclinical studies have shown that angiogenesis and apoptosis play crucial roles in the pathogenesis of DR. Increasing evidence suggests that in DR, the small guanosine-5'-triphosphate-binding protein RhoA activates its downstream targets mammalian Diaphanous homolog 1 (mDia-1) and profilin-1, thus affecting important cellular functions, including cell morphology, motility, secretion, proliferation, and gene expression. However, the specific underlying mechanism of disease remains unclear.

CONCLUSION

This review focuses on the RhoA/mDia-1/profilin-1 signaling pathway that specifically triggers endothelial dysfunction in diabetic patients. Recently, RhoA and profilin-1 signaling has attracted a great deal of attention in the context of diabetes-related research. However, the precise molecular mechanism by which the RhoA/mDia-1/profilin-1 pathway is involved in progression of microvascular endothelial dysfunction (MVED) during DR has not been determined. This review briefly describes each feature of the cascade before exploring the most recent findings on how the pathway may trigger endothelial dysfunction in DR. When the underlying mechanisms are understood, novel therapies seeking to restore the endothelial homeostasis comprised in DR will become possible.

FKBPL is a critical antiangiogenic regulator of developmental and pathological angiogenesis

OBJECTIVE

The antitumor effects of FK506-binding protein like (FKBPL) and its extracellular role in angiogenesis are well characterized; however, its role in physiological/developmental angiogenesis and the effect of FKBPL ablation has not been evaluated. This is important as effects of some angiogenic proteins are dosage dependent. Here we evaluate the regulation of FKBPL secretion under angiogenic stimuli, as well as the effect of FKBPL ablation in angiogenesis using mouse and zebrafish models.

APPROACH AND RESULTS

FKBPL is secreted maximally by human microvascular endothelial cells and fibroblasts, and this was specifically downregulated by proangiogenic hypoxic signals, but not by the angiogenic cytokines, VEGF or IL8. FKBPL's critical role in angiogenesis was supported by our inability to generate an Fkbpl knockout mouse, with embryonic lethality occurring before E8.5. However, whilst Fkbpl heterozygotic embryos showed some vasculature irregularities, the mice developed normally. In murine angiogenesis models, including the ex vivo aortic ring assay, in vivo sponge assay, and tumor growth assay, Fkbpl(+/-) mice exhibited increased sprouting, enhanced vessel recruitment, and faster tumor growth, respectively, supporting the antiangiogenic function of FKBPL. In zebrafish, knockdown of zFkbpl using morpholinos disrupted the vasculature, and the phenotype was rescued with hFKBPL. Interestingly, this vessel disruption was ineffective when zcd44 was knocked-down, supporting the dependency of zFkbpl on zCd44 in zebrafish.

CONCLUSIONS

FKBPL is an important regulator of angiogenesis, having an essential role in murine and zebrafish blood vessel development. Mouse models of angiogenesis demonstrated a proangiogenic phenotype in Fkbpl heterozygotes.

Functions of the Hsp90-binding FKBP immunophilins

Hsp90 functionally interacts with a broad array of client proteins, but in every case examined Hsp90 is accompanied by one or more co-chaperones. One class of co-chaperone contains a tetratricopeptide repeat domain that targets the co-chaperone to the C-terminal region of Hsp90. Within this class are Hsp90-binding peptidylprolyl isomerases, most of which belong to the FK506-binding protein (FKBP) family. Despite the common association of FKBP co-chaperones with Hsp90, it is now clear that the client protein influences, and is influenced by, the particular FKBP bound to Hsp90. Examples include Xap2 in aryl hydrocarbon receptor complexes and FKBP52 in steroid receptor complexes. In this chapter, we discuss the known functional roles played by FKBP co-chaperones and, where possible, relate distinctive functions to structural differences between FKBP members.

Brefeldin A reduces anchorage-independent survival, cancer stem cell potential and migration of MDA-MB-231 human breast cancer cells

Cancer stem cells (CSCs) are a subset of cancer cells in tumors or established cancer cell lines that can initiate and sustain the growth of tumors in vivo. Cancer stem cells can be enriched in serum-free, suspended cultures that allow the formation of tumorspheres over several days to weeks. Brefeldin A (BFA) is a mycotoxin that induces endoplasmic reticulum (ER) stress in eukaryotic cells. We found that BFA, at sub-microgram per milliliter concentrations, preferentially induced cell death in MDA-MB-231 suspension cultures (EC₅₀: 0.016 µg/mL) compared to adhesion cultures. BFA also effectively inhibited clonogenic activity and the migration and matrix metalloproteinases-9 (MMP-9) activity of MDA-MB-231 cells. Western blotting analysis indicated that the effects of BFA may be mediated by the down-regulation of breast CSC marker CD44 and anti-apoptotic proteins Bcl-2 and Mcl-1, as well as the reversal of epithelial-mesenchymal transition. Furthermore, BFA also displayed selective cytotoxicity toward suspended MDA-MB-468 cells, and suppressed tumorsphere formation in T47D and MDA-MB-453 cells, suggesting that BFA may be effective against breast cancer cells of various phenotypes.

Targeting treatment-resistant breast cancer stem cells with FKBPL and its peptide derivative, AD-01, via the CD44 pathway

PURPOSE

FK506-binding protein like (FKBPL) and its peptide derivative, AD-01, have already shown tumor growth inhibition and CD44-dependent antiangiogenic activity. Here, we explore the ability of AD-01 to target CD44-positive breast cancer stem cells (BCSC).

EXPERIMENTAL DESIGN

Mammosphere assays and flow cytometry were used to analyze the effect of FKBPL overexpression/knockdown and AD-01 treatment ± other anticancer agents on BCSCs using breast cancer cell lines (MCF-7/MDA-231/ZR-75), primary patient samples, and xenografts. Delays in tumor initiation were evaluated in vivo. The anti-stem cell mechanisms were determined using clonogenic assays, quantitative PCR (qPCR), and immunofluorescence.

RESULTS

AD-01 treatment was highly effective at inhibiting the BCSC population by reducing mammosphere-forming efficiency and ESA(+)/CD44(+)/CD24(-) or aldehyde dehydrogenase (ALDH)(+) cell subpopulations in vitro and tumor initiation in vivo. The ability of AD-01 to inhibit the self-renewal capacity of BCSCs was confirmed; mammospheres were completely eradicated by the third generation. The mechanism seems to be due to AD-01-mediated BCSC differentiation shown by a significant decrease in the number of holoclones and an associated increase in meroclones/paraclones; the stem cell markers, Nanog, Oct4, and Sox2, were also significantly reduced. Furthermore, we showed additive inhibitory effects when AD-01 was combined with the Notch inhibitor, DAPT. AD-01 was also able to abrogate a chemo- and radiotherapy-induced enrichment in BCSCs. Finally, FKBPL knockdown led to an increase in Nanog/Oct4/Sox2 and an increase in BCSCs, highlighting a role for endogenous FKBPL in stem cell signaling.

CONCLUSIONS

AD-01 has dual antiangiogenic and anti-BCSC activity, which will be advantageous as this agent enters clinical trial.