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Peptidyl prolyl isomerases (PPIases) are well‐conserved protein‐folding enzymes that moonlight as regulators of bacterial virulence. Peptidyl prolyl isomerase A, PPiA (Rv0009) is a secretory protein of Mycobacterium tuberculosis that possesses sequence and structural similarity to eukaryotic cyclophilins. In this study, we validated the interaction of PPiA with stimulator of interferon genes (STING) using both, Escherichia coli‐based and mammalian in vitro expression systems. In vitro pull‐down assays confirmed that the cytosolic domain of STING interacts with PPiA, and moreover, we found that PPiA could induce dimerization of STING in macrophages. In silico docking analyses suggested that the PXXP (PDP) motif of PPiA is crucial for interaction with STING, and concordantly, mutations in the PDP domain (PPiA MUT‐II) abrogated this interaction, as well as the ability of PPiA to facilitate STING dimerization. In agreement with these observations, fluorescence microscopy demonstrated that STING and wild‐type PPiA, but not PPiA MUT‐II, could colocalize when expressed in HEK293 cells. Highlighting the importance of the PDP domain further, PPiA, but not PPiA MUT‐II could activate Tank binding kinase 1 (TBK1)‐interferon regulatory factor 3 (IRF3) signaling to promote the release of interferon‐beta (IFNβ). PPiA, but not PPiA MUT‐II expressed in Mycobacterium smegmatis induced IFNβ release and facilitated bacterial survival in macrophages in a STING‐dependent manner. The PPiA‐induced release of IFNβ was c‐GAS independent. We conclude that PPiA is a previously undescribed mycobacterial regulator of STING‐dependent type I interferon production from macrophages. [ABSTRACT FROM AUTHOR]

The opening of the mitochondrial permeability transition pore (PTP), a Ca2+‐dependent pore located in the inner mitochondrial membrane, triggers mitochondrial outer membrane permeabilization (MOMP) and induces organelle rupture. However, the underlying mechanism of PTP‐induced MOMP remains unclear. Mitochondrial carrier homolog 2 (MTCH2) mediates MOMP process by facilitating the recruitment of tBID to mitochondria. Here, we show that MTCH2 binds to cyclophilin D (CyPD) and promotes the dimerization of F‐ATP synthase via interaction with subunit j. The interplay between MTCH2 and subunit j coordinates MOMP and PTP to mediate the occurrence of mitochondrial permeability transition. Knockdown of CyPD, MTCH2 and subunit j markedly sensitizes cells to RSL3‐induced ferroptosis, which is prevented by MitoTEMPO, suggesting that mitochondrial permeability transition mediates ferroptosis defense. [ABSTRACT FROM AUTHOR]

Background and Hypothesis Cognitive deficits in schizophrenia are linked to dysfunctions of the dorsolateral prefrontal cortex (DLPFC), including alterations in parvalbumin (PV)-expressing interneurons (PVIs). Redox dysregulation and oxidative stress may represent convergence points in the pathology of schizophrenia, causing dysfunction of GABAergic interneurons and loss of PV. Here, we show that the mitochondrial matrix protein cyclophilin D (CypD), a critical initiator of the mitochondrial permeability transition pore (mPTP) and modulator of the intracellular redox state, is altered in PVIs in schizophrenia. Study Design Western blotting was used to measure CypD protein levels in postmortem DLPFC specimens of schizophrenic patients (n  = 27) and matched comparison subjects with no known history of psychiatric or neurological disorders (n  = 26). In a subset of this cohort, multilabel immunofluorescent confocal microscopy with unbiased stereological sampling methods were used to quantify (1) numbers of PVI across the cortical mantle (20 unaffected comparison, 14 schizophrenia) and (2) PV and CypD protein levels from PVIs in the cortical layers 2–4 (23 unaffected comparison, 18 schizophrenia). Study Results In schizophrenic patients, the overall number of PVIs in the DLPFC was not significantly altered, but in individual PVIs of layers 2–4 PV protein levels decreased along a superficial-to-deep gradient when compared to unaffected comparison subjects. These laminar-specific PVI alterations were reciprocally linked to significant CypD elevations both in PVIs and total DLPFC gray matter. Conclusions Our findings support previously reported PVI anomalies in schizophrenia and suggest that CypD-mediated mPTP formation could be a potential contributor to PVI dysfunction in schizophrenia. [ABSTRACT FROM AUTHOR]

The mitochondrial permeability transition pore (mPTP) is a supramolecular channel that regulates exchange of solutes across cristae membranes, with executive roles in mitochondrial function and cell death. The contribution of the mPTP to normal physiology remains debated, although evidence implicates the mPTP in mitochondrial inner membrane remodeling in differentiating progenitor cells. Here, we demonstrate that strict control over mPTP conductance shapes metabolic machinery as cells transit toward hematopoietic identity. Cells undergoing the endothelial-to-hematopoietic transition (EHT) tightly control chief regulatory elements of the mPTP. During EHT, maturing arterial endothelium restricts mPTP activity just prior to hematopoietic commitment. After transition in cellular identity, mPTP conductance is restored. In utero treatment with NIM811, a molecule that blocks sensitization of the mPTP to opening by Cyclophilin D (CypD), amplifies oxidative phosphorylation (OXPHOS) in hematopoietic precursors and increases hematopoiesis in the embryo. Additionally, differentiating pluripotent stem cells (PSCs) acquire greater organization of mitochondrial cristae and hematopoietic activity following knockdown of the CypD gene, Ppif. Conversely, knockdown of Opa1, a GTPase critical for proper cristae architecture, induces cristae irregularity and impairs hematopoiesis. These data elucidate a mechanism that regulates mitochondrial maturation in hematopoietic precursors and underscore a role for the mPTP in the acquisition of hematopoietic fate. Examination of mitochondria in embryonic blood cell development exposes a mechanism that regulates mitochondrial cristae biogenesis and function during the endothelial-to-hematopoietic transition. [ABSTRACT FROM AUTHOR]

Immunosuppression is a major hallmark of tumor progression in non‐small cell lung cancer (NSCLC). Cluster of differentiation 147 (CD147), an important pro‐tumorigenic factor, is closely linked to NSCLC immunosuppression. However, the role of CD147 di‐methylation in the immunosuppressive tumor microenvironment (TME) remains unclear. Here, di‐methylation of CD147 at Lys148 (CD147‐K148me2) is identified as a common post‐translational modification (PTM) in NSCLC that is significantly associated with unsatisfying survival outcomes among NSCLC sufferers, especially those in the advanced stages of the disease. The methyltransferase NSD2 catalyzes CD147 to generate CD147‐K148me2. Further analysis demonstrates that CD147‐K148me2 reestablishes the immunosuppressive TME and promotes NSCLC progression. Mechanistically, this modification promotes the interaction between cyclophilin A (CyPA) and CD147, and in turn, increases CCL5 gene transcription by activating p38‐ZBTB32 signaling, leading to increased NSCLC cell‐derived CCL5 secretion. Subsequently, CD147‐K148me2‐mediated CCL5 upregulation facilitates M2‐like tumor‐associated macrophage (TAM) infiltration in NSCLC tissues via CCL5/CCR5 axis‐dependent intercellular crosstalk between tumor cells and macrophages, which is inhibited by blocking CD147‐K148me2 with the targeted antibody 12C8. Overall, this study reveals the role of CD147‐K148me2‐driven intercellular crosstalk in the development of NSCLC immunosuppression, and provides a potential interventional strategy for PTM‐targeted NSCLC therapy. [ABSTRACT FROM AUTHOR]

Cyclophilins (Cyps), characterized as peptidyl-prolyl cis-trans isomerases (PPIases), are highly conserved and ubiquitous, playing a crucial role in protein folding and cellular signaling. This review summarizes the biochemical pathways mediated by Cyps, including their involvement in pathological states such as viral replication, inflammation, and cancer progression, to underscore the therapeutic potential of Cyp inhibition. The exploration of Cyp inhibitors (CypI) in this review, particularly non-immunosuppressive cyclosporine A (CsA) derivatives, highlights their significance as therapeutic agents. The structural and functional nuances of CsA derivatives are examined, including their efficacy, mechanism of action, and the balance between therapeutic benefits and off-target effects. The landscape of CypI is evaluated to emphasize the clinical need for targeted approaches to exploit the complex biology of Cyps and to propose future directions for research that may enhance the utility of non-immunosuppressive CsA derivatives in treating diseases where Cyps play a key pathological role. [ABSTRACT FROM AUTHOR]

AbstractThe neurogenetics and vision community recently mourned William L. Pak, PhD, whose pioneering work spearheaded the genetic, electrophysiological, and molecular bases of biological processes underpinning vision. This essay provides a historical background to the daunting challenges and personal experiences that carved the path to seminal findings. It also reflects on the intellectual framework, mentoring philosophy, and inspirational legacy of Bill Pak's research. An emphasis and perspectives are placed on the discoveries and implications to date of the phosphatidylinositol-specific phospholipase C (PI-PLC), NorpA, and the cyclophilin, NinaA of the fruit fly, Drosophila melanogaster, and their respective mammalian homologues, PI-PLCβ4, and cyclophilin-related protein, Ran-binding protein 2 (Ranbp2) in critical biological processes and diseases of photoreceptors and other neurons. [ABSTRACT FROM AUTHOR]

Cyclophilin A (CypA), the cellular receptor of the immunosuppressant cyclosporin A (CsA), is an abundant cytosolic protein and is involved in a variety of diseases. For example, CypA supports cancer proliferation and mediates viral infections, such as the human immunodeficiency virus 1 (HIV-1). Here, we present the design of PROTAC (proteolysis targeting chimera) compounds against CypA to induce its intracellular proteolysis and to investigate their effect on immune cells. Interestingly, upon connecting to E3 ligase ligands, both peptide-based low-affinity binders and CsA-based high-affinity binders can degrade CypA at nM concentration in HeLa cells and fibroblast cells. As the immunosuppressive effect of CsA is not directly associated with the binding of CsA to CypA but the inhibition of phosphatase calcineurin by the CypA:CsA complex, we investigated whether a CsA-based PROTAC compound could induce CypA degradation without affecting the activation of immune cells. P3, the most efficient PROTAC compound discovered from this study, could deplete CypA in lymphocytes without affecting cell proliferation and cytokine production. This work demonstrates the feasibility of the PROTAC approach in depleting the abundant cellular protein CypA at low drug dosage without affecting immune cells, allowing us to investigate the potential therapeutic effects associated with the endogenous protein in the future. [ABSTRACT FROM AUTHOR]

Protein evolution is guided by structural, functional, and dynamical constraints ensuring organismal viability. Pseudogenes are genomic sequences identified in many eukaryotes that lack translational activity due to sequence degradation and thus over time have undergone "devolution." Previously pseudogenized genes sometimes regain their protein-coding function, suggesting they may still encode robust folding energy landscapes despite multiple mutations. We study both the physical folding landscapes of protein sequences corresponding to human pseudogenes using the Associative Memory, Water Mediated, Structure and Energy Model, and the evolutionary energy landscapes obtained using direct coupling analysis (DCA) on their parent protein families. We found that generally mutations that have occurred in pseudogene sequences have disrupted their native global network of stabilizing residue interactions, making it harder for them to fold if they were translated. In some cases, however, energetic frustration has apparently decreased when the functional constraints were removed. We analyzed this unexpected situation for Cyclophilin A, Profilin-1, and Small Ubiquitin-like Modifier 2 Protein. Our analysis reveals that when such mutations in the pseudogene ultimately stabilize folding, at the same time, they likely alter the pseudogenes' former biological activity, as estimated by DCA. We localize most of these stabilizing mutations generally to normally frustrated regions required for binding to other partners. [ABSTRACT FROM AUTHOR]

Mitochondrial dysfunction is an early pathological feature of Alzheimer disease and plays a crucial role in the development and progression of Alzheimer's disease. Strategies to rescue mitochondrial function and cognition remain to be explored. Cyclophilin D (CypD), the peptidylprolyl isomerase F (PPIase), is a key component in opening the mitochondrial membrane permeability transition pore, leading to mitochondrial dysfunction and cell death. Blocking membrane permeability transition pore opening by inhibiting CypD activity is a promising therapeutic approach for Alzheimer's disease. However, there is currently no effective CypD inhibitor for Alzheimer's disease, with previous candidates demonstrating high toxicity, poor ability to cross the blood–brain barrier, compromised biocompatibility and low selectivity. Here, we report a new class of non-toxic and biocompatible CypD inhibitor, ebselen, using a conventional PPIase assay to screen a library of ∼2000 FDA-approved drugs with crystallographic analysis of the CypD-ebselen crystal structure (PDB code: 8EJX). More importantly, we assessed the effects of genetic and pharmacological blockade of CypD on Alzheimer's disease mitochondrial and glycolytic bioenergetics in Alzheimer's disease-derived mitochondrial cybrid cells, an ex vivo human sporadic Alzheimer's disease mitochondrial model, and on synaptic function, inflammatory response and learning and memory in Alzheimer's disease mouse models. Inhibition of CypD by ebselen protects against sporadic Alzheimer's disease- and amyloid-β-induced mitochondrial and glycolytic perturbation, synaptic and cognitive dysfunction, together with suppressing neuroinflammation in the brain of Alzheimer's disease mouse models, which is linked to CypD-related membrane permeability transition pore formation. Thus, CypD inhibitors have the potential to slow the progression of neurodegenerative diseases, including Alzheimer's disease, by boosting mitochondrial bioenergetics and improving synaptic and cognitive function. [ABSTRACT FROM AUTHOR]

The long-term high-fat diet (HFD) can cause myocardial lipotoxicity, which is characterized pathologically by myocardial hypertrophy, fibrosis, and remodeling and clinically by cardiac dysfunction and heart failure in patients with obesity and diabetes. Circular RNAs (circRNAs), a novel class of noncoding RNA characterized by a ring formation through covalent bonds, play a critical role in various cardiovascular diseases. However, few studies have been conducted to investigate the role and mechanism of circRNA in myocardial lipotoxicity. Here, we found that circ_005077, formed by exon 2–4 of Crmp1, was significantly upregulated in the myocardium of an HFD-fed rat. Furthermore, we identified circ_005077 as a novel ferroptosis-related regulator that plays a role in palmitic acid (PA) and HFD-induced myocardial lipotoxicity in vitro and in vivo. Mechanically, circ_005077 interacted with Cyclophilin A (CyPA) and inhibited its degradation via the ubiquitination proteasome system (UBS), thus promoting the interaction between CyPA and p47phox to enhance the activity of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase responsible for ROS generation, subsequently inducing ferroptosis. Therefore, our results provide new insights into the mechanisms of myocardial lipotoxicity, potentially leading to the identification of a novel therapeutic target for the treatment of myocardial lipotoxicity in the future. [ABSTRACT FROM AUTHOR]

A family of Peptidyl-prolyl isomerases (PPIases), called Cyclophilins, localize to numerous intracellular and extracellular locations where they contribute to a variety of essential functions. We previously reported that non-immunosuppressive pan-cyclophilin inhibitor drugs like reconfilstat (CRV431) or NV556 decreased multiple aspects of non-alcoholic fatty liver disease (NAFLD) in mice under two different non-alcoholic steatohepatitis (NASH) mouse models. Both CRV431 and NV556 inhibit several cyclophilin isoforms, among which cyclophilin D (CypD) has not been previously investigated in this context. It is unknown whether it is necessary to simultaneously inhibit multiple cyclophilin family members to achieve therapeutic benefits or if loss-of-function of one is sufficient. Furthermore, narrowing down the isoform most responsible for a particular aspect of NAFLD/NASH, such as hepatocellular carcinoma (HCC), would allow for more precise future therapies. Features of human diabetes-linked NAFLD/NASH can be reliably replicated in mice by administering a single high dose of streptozotocin to disrupt pancreatic beta cells, in conjunction with a high sugar, high fat, high cholesterol western diet over the course of 30 weeks. Here we show that while both wild-type (WT) and Ppif-/- CypD KO mice develop multipe severe NASH disease features under this model, the formation of HCC nodules was significantly blunted only in the CypD KO mice. Furthermore, of differentially expressed transcripts in a qPCR panel of select HCC-related genes, nearly all were downregulated in the CypD KO background. Cyclophilin inhibition is a promising and novel avenue of treatment for diet-induced NAFLD/NASH. This study highlights the impact of CypD loss-of-function on the development of HCC, one of the most severe disease outcomes. [ABSTRACT FROM AUTHOR]

Human myxovirus resistance 2 (MX2/MXB) is an interferon-induced GTPase that inhibits human immunodeficiency virus-1 (HIV-1) infection by preventing nuclear import of the viral preintegration complex. The HIV-1 capsid (CA) is the major viral determinant for sensitivity to MX2, and complex interactions between MX2, CA, nucleoporins (Nups), cyclophilin A (CypA), and other cellular proteins influence the outcome of viral infection. To explore the interactions between MX2, the viral CA, and CypA, we utilized a CRISPR-Cas9/AAV approach to generate CypA knock-out cell lines as well as cells that express CypA from its endogenous locus, but with specific point mutations that would abrogate CA binding but should not affect enzymatic activity or cellular function. We found that infection of CypA knock-out and point mutant cell lines with wild-type HIV-1 and CA mutants recapitulated the phenotypes observed upon cyclosporine A (CsA) addition, indicating that effects of CsA treatment are the direct result of blocking CA-CypA interactions and are therefore independent from potential interactions between CypA and MX2 or other cellular proteins. Notably, abrogation of GTP hydrolysis by MX2 conferred enhanced antiviral activity when CA-CypA interactions were abolished, and this effect was not mediated by the CA-binding residues in the GTPase domain, or by phosphorylation of MX2 at position T151. We additionally found that elimination of GTPase activity also altered the Nup requirements for MX2 activity. Our data demonstrate that the antiviral activity of MX2 is affected by CypA-CA interactions in a virus-specific and GTPase activity-dependent manner. These findings further highlight the importance of the GTPase domain of MX2 in regulation of substrate specificity and interaction with nucleocytoplasmic trafficking pathways. Author summary: HIV-1 entry into the nucleus is an essential step in viral replication that involves complex interactions between the viral capsid and multiple cellular proteins, including the proline isomerase cyclophilin A. Nuclear entry of HIV-1 and other primate lentiviruses is inhibited by the antiviral protein MX2. Here, we show that direct interactions between capsid and cyclophilin A affect the antiviral activity and specificity of MX2, and that these interactions are altered when the enzymatic activity of MX2 is eliminated. We demonstrate that abolishing enzymatic activity of MX2 also alters the requirements for nuclear pore complex components for viral restriction. Our study provides new insights into how the enzymatic function of MX2 affects inhibition of lentiviral nuclear import. [ABSTRACT FROM AUTHOR]

Cyclophilin A, a widely prevalent cellular protein, exhibits peptidyl-prolyl cis-trans isomerase activity. This protein is predominantly located in the cytosol; additionally, it can be secreted by the cells in response to inflammatory stimuli. Cyclophilin A has been identified to be a key player in many of the biological events and is therefore involved in several diseases, including vascular and inflammatory diseases, immune disorders, aging, and cancers. It represents an attractive target for therapeutic intervention with small molecule inhibitors such as cyclosporin A. Recently, a number of novel inhibitors of cyclophilin A have emerged. However, it remains elusive whether and how many cyclophilin A inhibitors function in the inflammatory diseases and cancers. In this review, we discuss current available data about cyclophilin A inhibitors, including cyclosporin A and its derivatives, quinoxaline derivatives, and peptide analogues, and outline the most recent advances in clinical trials of these agents. Inhibitors of cyclophilin A are poised to enhance our comprehension of the molecular mechanisms that underpin inflammatory diseases and cancers associated with cyclophilin A. This advancement will aid in the development of innovative pharmaceutical treatments in the future. [ABSTRACT FROM AUTHOR]

Introduction: Loss of proteasome function, proteinopathy, and proteotoxicity may cause neurodegeneration across the human lifespan in several forms of brain injury and disease. Drugs that activate brain proteasomes in vivo could thus have a broad therapeutic impact in neurology. Methods: Using pigs, a clinically relevant large animal with a functionally compartmental gyrencephalic cerebral cortex, we evaluated the localization and biochemical activity of brain proteasomes and tested the ability of small molecules to activate brain proteasomes. Results: By Western blotting, proteasome protein subunit PSMB5 and PSMA3 levels were similar in different pig brain regions. Immunohistochemistry for PSMB5 showed localization in the cytoplasm (diffuse and particulate) and nucleus (cytoplasm < nucleus). Some PSMB5 immunoreactivity was colocalized with mitochondrial (voltage-gated anion channel and cyclophilin D) and cell death (Aven) proteins in the neuronal soma and neuropil in the neocortex of pig and human brains. In the nucleus, PSMB5 immunoreactivity was diffuse, particulate, and clustered, including perinucleolar decorations. By fluorogenic assay, proteasome chymotrypsin-like activities (CTL) in crude tissue soluble fractions were generally similar within eight different pig brain regions. Proteasome CTL activity in the hippocampus was correlated with activity in nasal mucosa biopsies. In pilot analyses of subcellular fractions of pig cerebral cortex, proteasome CTL activity was highest in the cytosol and then ~50% lower in nuclear fractions; ~15-20% of total CTL activity was in pure mitochondrial fractions. With in-gel activity assay, 26S-singly and -doubly capped proteasomes were the dominant forms in the pig cerebral cortex. With a novel in situ histochemical activity assay, MG132-inhibitable proteasome CTL activity was localized to the neuropil, as a mosaic, and to cell bodies, nuclei, and centrosome-like perinuclear satellites. In piglets treated intravenously with pyrazolone derivative and chlorpromazine over 24 h, brain proteasome CTL activity was modestly increased. Discussion: This study shows that the proteasome in the pig brain has relative regional uniformity, prominent nuclear and perinuclear presence with catalytic activity, a mitochondrial association with activity, 26S-single cap dominance, and indications from small molecule systemic administration of pyrazolone derivative and chlorpromazine that brain proteasome function appears safely activable. [ABSTRACT FROM AUTHOR]

Mastitis is one of the most frequent and costly diseases affecting dairy cattle. Natural antibodies (immunoglobulins) and cyclophilin A (CyPA), the most abundant member of the family of peptidyl prolyl cis / trans isomerases, in milk may serve as indicators of mastitis resistance in dairy cattle. However, genetic information for CyPA is not available, and knowledge on the genetic and nongenetic relationships between these immune-related traits and somatic cell score (SCS) and milk yield in dairy cattle is sparse. Therefore, we aimed to comprehensively evaluate whether immune-related traits consisting of 5 Ig classes (IgG, IgG 1 , IgG 2 , IgA, and IgM) and CyPA in the test-day milk of Holstein cows can be used as genetic indicators of mastitis resistance by evaluating the genetic and nongenetic relationships with SCS in milk. The nongenetic factors affecting immune-related traits and the effects of these traits on SCS were evaluated. Furthermore, the genetic parameters of immune-related traits according to health status and genetic relationships under different SCS environments were estimated. All immune-related traits were significantly associated with SCS and directly proportional. Additionally, evaluation using a classification tree revealed that IgA, IgG 2 , and IgG were associated with SCS levels. Genetic factor analyses indicated that heritability estimates were low for CyPA (0.08) but moderate for IgG (0.37), IgA (0.44), and IgM (0.44), with positive genetic correlations among Ig (0.25–0.96). We also evaluated the differences in milk yield and SCS of cows between the low and high groups according to their sires' estimated breeding value for immune-related traits. In the high group, IgA had a significantly lower SCS in milk at 7 to 30 d compared with that in the low group. Furthermore, the Ig in milk had high positive genetic correlations between healthy and infected conditions (0.82–0.99), suggesting that Ig in milk under healthy conditions could interact with those under infected conditions, owing to the genetic ability based on the level of Ig in milk. Thus, Ig in milk are potential indicators for the genetic selection of mastitis resistance. However, because only the relationship between immune-related traits and SCS was investigated in this study, further study on the relationship between clinical mastitis and Ig in milk is needed before Ig can be used as an indicator of mastitis resistance. [ABSTRACT FROM AUTHOR]

Cyclophilins are a diverse family of peptidyl-prolyl isomerases (PPIases) of importance in a variety of essential cellular functions. We previously reported that the pan-cyclophilin inhibitor drug reconfilstat (CRV431) decreased disease in mice under the western-diet and carbon tetrachloride (CCl4) non-alcoholic steatohepatitis (NASH) model. CRV431 inhibits several cyclophilin isoforms, among which cyclophilin A (CypA) and B (CypB) are the most abundant. It is not known whether simultaneous inhibition of multiple cyclophilin family members is necessary for the observed therapeutic effects or if loss-of-function of one is sufficient. Identifying the responsible isoform(s) would enable future fine-tuning of drug treatments. Features of human liver fibrosis and complete NASH can be reliably replicated in mice by administration of intraperitoneal CCl4 alone or CCl4 in conjunction with high sugar, high cholesterol western diet, respectively. Here we show that while wild-type (WT) and Ppia-/- CypA KO mice develop severe NASH disease features under these models, Ppib-/- CypB KO mice do not, as measured by analysis of picrosirius red and hematoxylin & eosin-stained liver sections and TNFα immuno-stained liver sections. Cyclophilin inhibition is a promising and novel avenue of treatment for diet-induced NASH. In this study, mice without CypB, but not mice without CypA, were significantly protected from the development of the characteristic features of NASH. These data suggest that CypB is necessary for NASH disease progression. Further investigation is necessary to determine whether the specific role of CypB in the endoplasmic reticulum secretory pathway is of significance to its effect on NASH development. [ABSTRACT FROM AUTHOR]

Aims Cyclophilin A (CyPA) induces leucocyte recruitment and platelet activation upon release into the extracellular space. Extracellular CyPA therefore plays a critical role in immuno-inflammatory responses in tissue injury and thrombosis upon platelet activation. To date, CD147 (EMMPRIN) has been described as the primary receptor mediating extracellular effects of CyPA in platelets and leucocytes. The receptor for advanced glycation end products (RAGE) shares inflammatory and prothrombotic properties and has also been found to have similar ligands as CD147. In this study, we investigated the role of RAGE as a previously unknown interaction partner for CyPA. Methods and results Confocal imaging, proximity ligation, co-immunoprecipitation, and atomic force microscopy were performed and demonstrated an interaction of CyPA with RAGE on the cell surface. Static and dynamic cell adhesion and chemotaxis assays towards extracellular CyPA using human leucocytes and leucocytes from RAGE-deficient Ager −/− mice were conducted. Inhibition of RAGE abrogated CyPA-induced effects on leucocyte adhesion and chemotaxis in vitro. Accordingly, Ager −/− mice showed reduced leucocyte recruitment and endothelial adhesion towards CyPA in vivo. In wild-type mice, we observed a downregulation of RAGE on leucocytes when endogenous extracellular CyPA was reduced. We furthermore evaluated the role of RAGE for platelet activation and thrombus formation upon CyPA stimulation. CyPA-induced activation of platelets was found to be dependent on RAGE, as inhibition of RAGE, as well as platelets from Ager −/− mice showed a diminished activation and thrombus formation upon CyPA stimulation. CyPA-induced signalling through RAGE was found to involve central signalling pathways including the adaptor protein MyD88, intracellular Ca2+ signalling, and NF-κB activation. Conclusion We propose RAGE as a hitherto unknown receptor for CyPA mediating leucocyte as well as platelet activation. The CyPA–RAGE interaction thus represents a novel mechanism in thrombo-inflammation. [ABSTRACT FROM AUTHOR]

Cyclophilin A regulates the biological behavior of placental trophoblast cells in severe preeclampsia by regulating oxygen inducible factor (hypoxia-inducible factor-1 alpha) signal pathway. JEG3 cell line was selected and randomly divided into control group (minimum essential medium 1 l containing 10 % fetal bovine serum) (group A), low dose group (cyclophilin A protein concentration was 1 pg/ml) (group B) and high dose group (cyclophilin A protein concentration was 3 pg/ml) (group C). The apoptosis of JEG3 cells was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling method, the expression of tumor necrosis factor-alpha, interleukin-6 and interleukin-1 beta messenger ribonucleic acid in JEG3 cells was detected by quantitative read-time polymerase chain reaction method, and the expression of cleaved caspase-3, caspase-3, cleaved poly (ADP-ribose) polymerase 1, poly (ADP-ribose) polymerase 1, p53 and hypoxia-inducible factor-1 alpha protein was detected by Western bolting. Quantitative polymerase chain reaction assay showed that the expression levels of tumor necrosis factor-alpha, interleukin-6 and interleukin-1 beta in group B and group C were raised than those in group A, and the expression levels of tumor necrosis factor-alpha, interleukin-6 and interleukin-1 beta increased with the increase of cyclophilin A concentration. Western blotting detection showed that the cleaved caspase-3 expression level of JEG3 cells in group B and C was raised than that in group A, and increased with the increase of concentration, while the expression of cleaved poly (ADP-ribose) polymerase 1 in group C was raised than that in group A. The levels of hypoxia-inducible factor-1 alpha in JEG3 cells were higher in both the group B and C compared to the group A, and they further increased with the rise in concentration. Cyclophilin A can promote inflammation by increasing the expression of tumor necrosis factor-alpha, interleukin-6 and interleukin-1 beta in trophoblasts, and accelerate the apoptosis of trophoblasts by activating caspase-3 pathway, which is an important pathogenic factor of preeclampsia. This mechanism may be related to the regulation of hypoxia-inducible factor-1 alpha signal pathway. [ABSTRACT FROM AUTHOR]

Influenza virus has been one of the most prevalent and researched viruses globally. Consequently, there is ample information available about influenza virus lifecycle and pathogenesis. However, there is plenty yet to be known about the determinants of influenza virus pathogenesis and disease severity. Influenza virus exploits host factors to promote each step of its lifecycle. In turn, the host deploys antiviral or restriction factors that inhibit or restrict the influenza virus lifecycle at each of those steps. Two broad categories of host restriction factors can exist in virus-infected cells: (1) encoded by the interferon-stimulated genes (ISGs) and (2) encoded by the constitutively expressed genes that are not stimulated by interferons (non-ISGs). There are hundreds of ISGs known, and many, e.g., Mx, IFITMs, and TRIMs, have been characterized to restrict influenza virus infection at different stages of its lifecycle by (1) blocking viral entry or progeny release, (2) sequestering or degrading viral components and interfering with viral synthesis and assembly, or (3) bolstering host innate defenses. Also, many non-ISGs, e.g., cyclophilins, ncRNAs, and HDACs, have been identified and characterized to restrict influenza virus infection at different lifecycle stages by similar mechanisms. This review provides an overview of those ISGs and non-ISGs and how the influenza virus escapes the restriction imposed by them and aims to improve our understanding of the host restriction mechanisms of the influenza virus. [ABSTRACT FROM AUTHOR]

Simple Summary: Colorectal cancer ranks as the second most common cause of cancer-related deaths. In this research, we analyzed the prognostic and predictive roles of three potential serum biomarkers (Cyclophilin A (CypA), copeptin and Tie2) in 56 patients with metastatic colorectal cancer treated with bevacizumab and chemotherapy. We assessed the serum levels of biomarkers before and after one and six months of therapy. Based on Kaplan–Meier curves and multivariate Cox analysis, low levels of CypA at baseline and after one month of treatment were associated with better overall survival, being independent prognostic factors after adjustment for baseline and post-treatment factors. For copeptin and Tie2, the results show no correlation between these biomarkers and overall survival or progression-free survival. Colorectal cancer (CRC) ranks as second most common cause of cancer-related deaths. The CRC management considerably improved in recent years, especially due to biological therapies such as bevacizumab. The lack of predictive or prognostic biomarkers remains one of the major disadvantages of using bevacizumab in the CRC management. We performed a prospective study to analyze the prognostic and predictive roles of three potential serum biomarkers (Cyclophilin A (CypA), copeptin and Tie2) investigated by ELISA in 56 patients with metastatic CRC undergoing bevacizumab and chemotherapy between May 2019 and September 2021 at baseline and after one and six months of therapy. We showed that low levels of CypA at baseline and after one month of treatment were associated with better overall survival (OS) (42 versus 24 months, p = 0.029 at baseline; 42 versus 25 months, p = 0.039 after one month). For copeptin and Tie2, Kaplan–Meier curves showed no correlation between these biomarkers and OS or progression-free survival. When adjusting for baseline and post-treatment factors, a multivariate Cox analysis showed that low values of CypA at baseline and after one month of treatment were independent prognostic factors for OS and correlated with a better prognosis in metastatic CRC patients. [ABSTRACT FROM AUTHOR]

Cyclophilin A (CypA), the first member of cyclophilins, is distributed extensively in eukaryotic and prokaryotic cells, primarily localized in the cytoplasm. In addition to acting as an intracellular receptor for cyclosporin A (CSA), CypA plays a crucial role in diseases such as aging and tumorigenesis. Apoptosis, a form of programmed cell death, is able to balance the rate of cell viability and death. In this review, we focus on the effects of CypA on apoptosis and the relationship between specific mechanisms of CypA promoting or inhibiting apoptosis and diseases, including tumorigenesis, cardiovascular diseases, organ injury, and microbial infections. Notably, the process of CypA promoting or inhibiting apoptosis is closely related to disease development. Finally, future prospects for the association of CypA and apoptosis are discussed, and a comprehensive understanding of the effects of CypA on apoptosis in relation to diseases is expected to provide new insights into the design of CypA as a therapeutic target for diseases. Key points: • Understand the effect of CypA on apoptosis. • CypA affects apoptosis through specific pathways. • The effect of CypA on apoptosis is associated with a variety of disease processes. [ABSTRACT FROM AUTHOR]

Introduction: Mild traumatic brain injury (mTBI) and hypertension synergize to induce persistent disruption of the blood–brain barrier (BBB), neuroinflammation and cognitive decline. However, the underlying mechanisms are not known. Cerebral production of Cyclophilin A (CyPA) is induced in hypertension and after TBI, and it was demonstrated to activate the nuclear factor-κB (NF-kB)- matrix-metalloproteinase-9 (MMP-9) pathway in cerebral vessels leading to BBB disruption. Methods: To test the role of CyPA in mTBI- and hypertension-induced BBB disruption we induced mTBI in normotensive and spontaneously hypertensive rats (SHR), then the animals were treated with cyclosporine A (a specific inhibitor of CyPA production) or vehicle for 7 days. We assessed BBB permeability and integrity, cerebral expression and activity of the CyPA-NF-kB-MMP-9 pathway, extravasation of fibrin and neuroinflammation. Results: We found that mild TBI induced BBB disruption and upregulation of the CyPANF- kB-MMP-9 pathway in hypertension, which were prevented by blocking CyPA. Cyclosporine treatment and preservation of BBB function prevented accumulation of blood-derived fibrin in the brain parenchyma of hypertensive rats after mTBI and reversed increased neuroinflammation. Discussion: We propose that mTBI and hypertension interact to promote BBB disruption via the CyPA-NF-kB-MMP-9 pathway, and inhibition of cyclophilin production after mTBI may exert neuroprotection and improve cognitive function in hypertensive patients. [ABSTRACT FROM AUTHOR]

Stuttering is a common speech disorder that interrupts speech fluency and tends to cluster in families. Typically, stuttering is characterized by speech sounds, words or syllables which may be repeated or prolonged and speech that may be further interrupted by hesitations or 'blocks'. Rare variants in a small number of genes encoding lysosomal pathway proteins have been linked to stuttering. We studied a large four-generation family in which persistent stuttering was inherited in an autosomal dominant manner with disruption of the cortico-basal-ganglia-thalamo-cortical network found on imaging. Exome sequencing of three affected family members revealed the PPID c.808C>T (p.Pro270Ser) variant that segregated with stuttering in the family. We generated a Ppid p.Pro270Ser knock-in mouse model and performed ex vivo imaging to assess for brain changes. Diffusion-weighted MRI in the mouse revealed significant microstructural changes in the left corticospinal tract, as previously implicated in stuttering. Quantitative susceptibility mapping also detected changes in cortico-striatal-thalamo-cortical loop tissue composition, consistent with findings in affected family members. This is the first report to implicate a chaperone protein in the pathogenesis of stuttering. The humanized Ppid murine model recapitulates network findings observed in affected family members. [ABSTRACT FROM AUTHOR]

The rather few cases of humans infected by HIV-1 N, O, or P raise the question of their incomplete adaptation to humans. We hypothesized that early postentry restrictions may be relevant for the impaired spread of these HIVs. One of the best-characterized species-specific restriction factors is TRIM5α. HIV-1 M can escape human (hu) TRIM5a restriction by binding cyclophilin A (CYPA, also known as PPIA, peptidylprolyl isomerase A) to the so-called CYPA-binding loop of its capsid protein. How non-M HIV-1s interact with huTRIM5a is ill-defined. By testing full-length reporter viruses (κ env) of HIV-1 N, O, P, and SIVgor (simian IV of gorillas), we found that in contrast to HIV-1 M, the nonpandemic HIVs and SIVgor showed restriction by huTRIM5α. Work to identify capsid residues that mediate susceptibility to huTRIM5α revealed that residue 88 in the capsid CYPA-binding loop was important for such differences. There, HIV-1 M uses alanine to resist, while non-M HIV-1s have either valine or methionine, which avail them for huTRIM5α. Capsid residue 88 determines the sensitivity to TRIM5α in an unknown way. Molecular simulations indicated that capsid residue 88 can affect trans-to-cis isomerization patterns on the capsids of the viruses we tested. These differential CYPA usages by pandemic and nonpandemic HIV-1 suggest that the enzymatic activity of CYPA on the viral core might be important for its protective function against huTRIM5α. [ABSTRACT FROM AUTHOR]

Penicillium species are an industrially important group of fungi. Cyclophilins are ubiquitous proteins and several members of this family exhibit peptidyl-prolyl cis–trans isomerase (PPIase) activity. We had earlier demonstrated that the salt-induced PPIase activity in a halotolerant strain of P. oxalicum was associated with enhanced expression of a cyclophilin gene, PoxCYP18. Cloning and characterization of PoxCYP18 revealed that its cDNA consists of 522 bp encoding a protein of 173 amino acid residues, with predicted molecular mass and pI values of 18.91 kDa and 8.87, respectively. The recombinant PoxCYP18 can catalyze cis–trans isomerization of peptidyl-prolyl bond with a catalytic efficiency of 1.46 × 107 M−1 s−1 and is inhibited specifically only by cyclosporin A, with an inhibition constant of 5.04 ± 1.13 nM. PoxCYP18 consists of two cysteine residues at positions − 45 and − 170, and loses its activity under oxidizing conditions. Substitution of these residues alone or together by site-directed mutagenesis revealed that the PPIase activity of PoxCYP18 is regulated through a redox mechanism involving the formation of disulfide linkages. Heterologous expression of PoxCYP18 conferred enhanced tolerance to salt stress in transgenic E. coli cells, implying that this protein imparts protection to cellular processes against salt-induced damage. [ABSTRACT FROM AUTHOR]

Cyclophilin E (CypE) belongs to the cyclophilin family and exhibits peptidyl-prolyl cis-trans isomerase (PPIase) activity. It participates in various biological processes through the regulation of peptidyl-prolyl isomerization. However, the specific role of CypE in osteoblast differentiation has not yet been elucidated. In this study, we first discovered the positive impact of CypE on osteoblast differentiation through gain or loss of function experiments. Mechanistically, CypE enhances the transcriptional activity of Runx2 through its PPIase activity. Furthermore, we identified the involvement of the Akt signaling pathway in CypE's function in osteoblast differentiation. Taken together, our findings indicate that CypE plays an important role in osteoblast differentiation as a positive regulator by increasing the transcriptional activity of Runx2. [ABSTRACT FROM AUTHOR]

The HIV-1 genome encodes a small number of proteins with structural, enzymatic, regulatory, and accessory functions. These viral proteins interact with a number of host factors to promote the early and late stages of HIV-1 infection. During the early stages of infection, interactions between the viral proteins and host factors enable HIV-1 to enter the target cell, traverse the cytosol, dock at the nuclear pore, gain access to the nucleus, and integrate into the host genome. Similarly, the viral proteins recruit another set of host factors during the late stages of infection to orchestrate HIV-1 transcription, translation, assembly, and release of progeny virions. Among the host factors implicated in HIV-1 infection, Cyclophilin A (CypA) was identified as the first host factor to be packaged within HIV-1 particles. It is now well established that CypA promotes HIV-1 infection by directly binding to the viral capsid. Mechanistic models to pinpoint CypA's role have spanned from an effect in the producer cell to the early steps of infection in the target cell. In this review, we will describe our understanding of the role(s) of CypA in HIV-1 infection, highlight the current knowledge gaps, and discuss the potential role of this host factor in the post-nuclear entry steps of HIV-1 infection. [ABSTRACT FROM AUTHOR]

There is an urgent need for the identification of new drugs that inhibit HCV-induced hepatocellular carcinoma (HCC). Our work demonstrates that cyclophilin inhibitors (CypIs) represent such new drugs. We demonstrate that the nonimmunosuppressive cyclosporine A (CsA) analog (CsAa) rencofilstat possesses dual therapeutic activities for the treatment of HCV infection and HCV-induced HCC. Specifically, we show that the HCV infection of humanized mice results in the progressive development of HCC. This is true for the four genotypes tested (1 to 4). Remarkably, we demonstrate that rencofilstat inhibits the development of HCV-induced HCC in mice even when added 16 weeks after infection when HCC is well established. Importantly, we show that rencofilstat drastically reduces HCC progression independently of its anti-HCV activity. Indeed, the CypI rencofilstat inhibits HCC, while other anti-HCV agents such as NS5A (NS5Ai) and NS5B (NS5Bi) fail to reduce HCC. In conclusion, this study shows for the first time that the CypI rencofilstat represents a potent therapeutic agent for the treatment of HCV-induced HCC. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) play an important role in gene regulation. In Arabidopsis, mature miRNAs are processed from primary miRNA transcripts by the Dicing complex that contains Dicer-like 1 (DCL1), SERRATE (SE), and Hyponastic Leaves 1 (HYL1). The Dicing complex can form nuclear dicing bodies (D-bodies) through SE phase separation. Here, we report that Cyclophilin71 (CYP71), a peptidyl-prolyl isomerase (PPIase), positively regulates miRNA processing. We show that CYP71 directly interacts with SE and enhances its phase separation, thereby promoting the formation of D-body and increasing the activity of the Dicing complex. We further show that the PPIase activity is important for the function of CYP71 in miRNA production. Our findings reveal orchestration of miRNA processing by a cyclophilin protein and suggest the involvement of peptidyl-prolyl cis–trans isomerization, a structural mechanism, in SE phase separation and miRNA processing. [ABSTRACT FROM AUTHOR]

Cyclophilins (CyPs) are involved in basic cellular functions and a wide variety of pathophysiological processes. Many CyPs have been identified as the aetiological agent and influence on the immune system. In the present study, the physicochemical and immunologic characteristics of three proteins of CyPs family (CyPA, CyPB and CyPE) were analyzed. The results indicated that CyPE showed a closer evolutionary relationship with allergenic CyPA. The structure and antigenicity of CyPE was significantly similar with CyPA. B-cell epitopes of CyPE and CyPA were predicted via multiple immunoinformatics tools. Three consensus B-cell epitopes of CyPE and CyPAs were finally determined. To verify results of in silico analysis, three proteins of CyPs family (CyPA, CyPE and CyPB) were cloned and expressed from Dermatophagoides pteronyssinus. ELISA results indicated that the positive reaction rates of the three proteins to patient serum are CyPA (21.4%), CyPE (7.1%), and CyPB (0%), illustrating that the IgE activity was exhibited in CypA and CypE excluding CyPB. Structure and immunoinformatics analysis demonstrated that the RNA-binding motif of CyPE could reduce the immunogenicity of PPIase domain of CyPE. The reason that CyPB has no IgE activity might be the structure mutation of CyPB on B-cell epitopes. [ABSTRACT FROM AUTHOR]

Mitochondrial dysfunction plays a pivotal role in numerous complex diseases. Understanding the molecular mechanisms by which the "powerhouse of the cell" turns into the "factory of death" is an exciting yet challenging task that can unveil new therapeutic targets. The mitochondrial matrix protein CyPD is a peptidylprolyl cis-trans isomerase involved in the regulation of the permeability transition pore (mPTP). The mPTP is a multi-conductance channel in the inner mitochondrial membrane whose dysregulated opening can ultimately lead to cell death and whose involvement in pathology has been extensively documented over the past few decades. Moreover, several mPTP-independent CyPD interactions have been identified, indicating that CyPD could be involved in the fine regulation of several biochemical pathways. To further enrich the picture, CyPD undergoes several post-translational modifications that regulate both its activity and interaction with its clients. Here, we will dissect what is currently known about CyPD and critically review the most recent literature about its involvement in neurodegenerative disorders, focusing on Alzheimer's Disease and Parkinson's Disease, supporting the notion that CyPD could serve as a promising therapeutic target for the treatment of such conditions. Notably, significant efforts have been made to develop CyPD-specific inhibitors, which hold promise for the treatment of such complex disorders. [ABSTRACT FROM AUTHOR]

Introduction: Multiple myeloma (MM) is a hematological blood cancer of the bone marrow that remains largely incurable, in part due to its physical interactions with the bone marrow microenvironment. Such interactions enhance the homing, proliferation, and drug resistance of MM cells. Specifically, adhesion receptors and homing factors, E-selectin (ES) and cyclophilin A (CyPA), respectively, expressed by bone marrow endothelial cells enhance MM colonization and dissemination. Thus, silencing of ES and CyPA presents a potential therapeutic strategy to evade MM spreading. However, small molecule inhibition of ES and CyPA expressed by bone marrow endothelial cells remains challenging, and blocking antibodies induce further MM propagation. Therefore, ES and CyPA are promising candidates for inhibition via RNA interference (RNAi). Methods: Here, we utilized a previously developed lipid–polymer nanoparticle for RNAi therapy, that delivers siRNA to the bone marrow perivascular niche. We utilized our platform to co-deliver ES and CyPA siRNAs to prevent MM dissemination in vivo. Results: Lipid-polymer nanoparticles effectively downregulated ES expression in vitro, which decreased MM cell adhesion and migration through endothelial monolayers. Additionally, in vivo delivery of lipid-polymer nanoparticles co-encapsulating ES and CyPA siRNA extended survival in a xenograft mouse model of MM, either alone or in combination with the proteasome inhibitor bortezomib. Conclusions: Our combination siRNA lipid-polymer nanoparticle therapy presents a vascular microenvironment-targeting strategy as a potential paradigm shift for MM therapies, which could be extended to other cancers that colonize the bone marrow. [ABSTRACT FROM AUTHOR]

Cyclophilins (CyPs) are a family of enzymes involved in protein folding. Trypanosoma cruzi, the causative agent of Chagas disease, has a 19-kDa cyclophilin, TcCyP19, that was found to be secreted in parasite stages of the CL Brener clone and recognized by sera from T. cruzi-infected mice and patients. The levels of specific antibodies against TcCyP19 in T. cruzi-infected mice and subjects before and after drug treatment were measured by an in-house enzyme linked immunosorbent assay (ELISA). Mice in the acute and chronic phase of infection, with successful trypanocidal treatments, showed significantly lower anti-TcCyP19 antibody levels than untreated mice. In children and adults chronically infected with T. cruzi, a significant decrease in the anti-TcCyP19 titers was observed after 12 months of etiological treatment. This decrease was maintained in adult chronic patients followed-up 30–38 months post-treatment. These results encourage further studies on TcCyP19 as an early biomarker of trypanocidal treatment efficiency. [ABSTRACT FROM AUTHOR]

Interferon-stimulated genes (ISG) and microRNA (miRNA) present in maternal circulation have been reported to be diagnostic of pregnancy in cattle prior to day (d)30 of gestation. The objective of this study was to assess specific ISG and miRNA abundance on d 18 of gestation. Cattle were subjected to estrous synchronization and artificially inseminated to a single Angus sire. At time of insemination (d 0) and d 18 post-insemination, blood was collected and total RNA isolated. Differential abundance (DA) in specific ISG and miRNA between d 0 and d 18 samples in pregnant (n = 10) and open (n = 10) cows were assessed via RT-qPCR. The relative Ct values were normalized using abundance of cyclophilin or the geometric mean of specific miRNA for the ISG and miRNA genes of interest, respectively. The DA of the ISG were increased due to pregnancy (p < 0.05); however, there was no expected day of gestation by pregnancy interaction. Relative abundance of Bta-miR-16 increased on d18 regardless of pregnancy status (p < 0.05). None of the miRNA evaluated in this study were associated with pregnancy status. These data indicate that certain ISG may serve as early indicators of pregnancy in cattle, but abundance of the miRNA does not. [ABSTRACT FROM AUTHOR]

The precise balance of Th1, Th2, and Th17 cytokines is a key factor in successful pregnancy and normal embryonic development. However, to date, not all humoral factors that regulate and influence physiological pregnancy have been completely studied. Our data here pointed out cyclophilin A (CypA) as the adverse pro-inflammatory factor negatively affecting fetal development and associated with pregnancy complications. In different mouse models in vivo, we demonstrated dramatic embryotoxicity and teratogenicity of increased CypA levels during pregnancy. Using generated transgenic models, we showed that CypA overexpression in fetal tissues induced the death of all transgenic fetuses and complete miscarriage. Administration of recombinant human CypA in a high dose to pregnant females during fetal organogenesis (6.5–11.5 dpc) exhibited teratogenic effects, causing severe defects in the brain and bone development that could lead to malformations and postnatal behavioral and cognitive disorders in the offspring. Embryotoxic and teratogenic effects could be mediated by CypA-induced up-regulation of M1 macrophage polarization via activation of the STAT1/3 signaling pathways. Here, we propose secreted CypA as a novel marker of complicated pregnancy and a therapeutic target for the correction of pregnancy complications. [ABSTRACT FROM AUTHOR]

Introduction: The high levels of angiotensin II (Ang II) can modify the vascular tone, enhance vascular smooth muscle cells (VSMCs) proliferation and hypertrophy and increase the inflammatory cellular infiltration into the vessel wall. The old herbal nonpharmacological agent, Hibiscus (HS) sabdariffa L has multiple cardioprotective impacts; thus, we investigated the role of HS extract in amelioration of renovascular hypertension (RVH)-induced aortic remodeling. Materials and methods: Thirty-five rats (7/group) were randomly allocated into 5 groups; group: I: Control-sham group, and RVH groups; II, III, IV, and V. The rats in RVH groups were subjected to the modified Goldblatt two-kidneys, one clip (2K1C) for induction of hypertension. In group: II, the rats were left untreated whereas in group III, IV, and V: RVH-rats were treated for 6 weeks with low dose hibiscus (LDH), medium dose hibiscus (MDH), and high dose hibiscus (HDH) respectively. Results: We found that the augmented pro-contractile response of the aortic rings was ameliorated secondary to the in-vivo treatment with HS dose dependently. The cyclophilin A (CyPA) protein levels positively correlated with the vascular adhesion molecule-1 (VCAM-1) and ERK1/2, which, in turn, contribute to the reactive oxygen species (ROS) production. Daily HS intake modified aortic renovation by enhancing the antioxidant capacity, restraining hypertrophy and fibrosis, downregulation of the metastasis associated lung adenocarcinoma transcript (MALAT1), and cyclophilin A (CyPA)/ERK1/2 levels. Discussion: Adding to the multiple beneficial effects, HS aqueous extract was able to inhibit vascular smooth muscle cell proliferation induced by 2K1C model. Thus, adding more privilege for the utilization of the traditional herbal extracts to attenuate RVH-induced aortopathy. [ABSTRACT FROM AUTHOR]

Cyclophilin D (CypD) is regulated during the innate immune response of insects. However, the mechanism by which CypD is activated under innate immunosuppression is not understood. Microplitis bicoloratus bracovirus (MbBV), a symbiotic virus in the parasitoid wasp, Microplitis bicoloratus, suppresses innate immunity in parasitized Spodoptera litura. Here, we demonstrate that MbBV promotes the CypD acetylation of S. litura, resulting in an immunosuppressive phenotype characterized by increased apoptosis of hemocytes and MbBV-infected cells. Under MbBV infection, the inhibition of CypD acetylation significantly rescued the apoptotic cells induced by MbBV, and the point-mutant fusion proteins of CypDK125R-V5 were deacetylated. The CypD-V5 fusion proteins were acetylated in MbBV-infected cells. Deacetylation of CypDK125R-V5 can also suppress the MbBV-induced increase in apoptosis. These results indicate that CypD is involved in the MbBV-suppressed innate immune response via the CypD-acetylation pathway and S. litura CypD is acetylated on K125. [ABSTRACT FROM AUTHOR]

The isomerase activity of Cyclophilin A is important for midbody abscission during cell division, however, to date, midbody substrates remain unknown. In this study, we report that the GTP-binding protein Septin 2 interacts with Cyclophilin A. We highlight a dynamic series of Septin 2 phenotypes at the midbody, previously undescribed in human cells. Furthermore, Cyclophilin A depletion or loss of isomerase activity is sufficient to induce phenotypic Septin 2 defects at the midbody. Structural and molecular analysis reveals that Septin 2 proline 259 is important for interaction with Cyclophilin A. Moreover, an isomerisation-deficient EGFP-Septin 2 proline 259 mutant displays defective midbody localisation and undergoes impaired abscission, which is consistent with data from cells with loss of Cyclophilin A expression or activity. Collectively, these data reveal Septin 2 as a novel interacting partner and isomerase substrate of Cyclophilin A at the midbody that is required for abscission during cytokinesis in cancer cells. [ABSTRACT FROM AUTHOR]

Quantitative real-time PCR (qRT-PCR) in sweet potatoes requires accurate data normalization; however, there are insufficient studies on appropriate reference genes for gene expression analysis. We examined variations in the expression of eight candidate reference genes in the leaf and root tissues of sweet potatoes (eight nonvirus-infected or eight virus-infected samples). Parallel analyses with geNorm, NormFinder, and Best-Keeper show that different viral infections and origin tissues affect the expression levels of these genes. Based on the results of the evaluation of the three software, the adenosine diphosphate-ribosylation factor is suitable for nonvirus or virus-infected sweet potato leaves. Cyclophilin and ubiquitin extension proteins are suitable for nonvirus-infected sweet potato leaves. Phospholipase D1 alpha is suitable for virus-infected sweet potato leaves. Actin is suitable for roots of nonvirus-infected sweet potatoes. Glyceraldehyde-3-phosphate dehydrogenase is suitable for virus-infected sweet potato roots. The research provides appropriate reference genes for further analysis in leaf and root samples of viruses in sweet potatoes. [ABSTRACT FROM AUTHOR]

This document is an erratum for three articles published in Critical Care Medicine. The first erratum corrects an error in an article about the interactions between Cyclophilin A and Cluster of Differentiation 147 in early brain injury after subarachnoid hemorrhage in rats. The second erratum corrects the title of an abstract about machine learning models for predicting mortality in sepsis. The third erratum corrects the final author listed in an article about pediatric lung disease in resource-limited settings. [Extracted from the article]

Cyclophilins are a family of chaperones involved in inflammation and cell death. Cyclophilin B is released by inflammatory cells and acts through the receptor CD147, affecting matrix metalloproteases release, whilst cyclophilin D participates in hypoxia-induced apoptosis. Previous studies related hormones like estradiol or prolactin to these proteins, however, their blood concentrations across the menstrual cycle have not been determined. In this work, eleven healthy women (BMI: 21.8 kg/m2) were monitored during a single menstrual cycle, making blood extractions at follicular, periovulatory and mid-luteal phases. Hormone and cyclophilin levels were determined in each phase. Statistical differences were determined by repeated measures ANOVA and estimated marginal means tests, or by Friedman and Dunn-Bonferroni tests for parametric and non-parametric variables, respectively. Bivariate correlations were evaluated with the Spearman coefficient. Cyclophilin B concentrations presented significant differences during the menstrual cycle (p = 0.012). The highest levels of this protein were found at follicular extraction, followed by a decrease at periovulatory phase and a slight increase at mid-luteal phase. Cyclophilin D showed the same profile, although statistical significance was not reached. This immunophilin exhibited a positive correlation with luteinizing hormone at periovulatory phase (r = 0.743, p = 0.009) and with follicle stimulating hormone at mid-luteal phase (r = 0.633, p = 0.036). This is the first study describing the changes in cyclophilin B concentrations across the menstrual cycle, as well as the association of luteinizing and follicle stimulating hormones with cyclophilin D. These results suggest a role of these proteins in the cyclic inflammatory events that affect female reproductive system that should be explored. [ABSTRACT FROM AUTHOR]

Non-small cell lung cancer (NSCLC) is a fatal malignant tumor with a high mortality rate. Cancer stem cells (CSCs) play pivotal roles in tumor initiation and progression, treatment resistance, and NSCLC recurrence. Therefore, the development of novel therapeutic targets and anticancer drugs that effectively block CSC growth may improve treatment outcomes in patients with NSCLC. In this study, we evaluated, for the first time, the effects of natural cyclophilin A (CypA) inhibitors, including 23-demethyl 8,13-deoxynargenicin (C9) and cyclosporin A (CsA), on the growth of NSCLC CSCs. C9 and CsA more sensitively inhibited the proliferation of epidermal growth factor receptor (EGFR)-mutant NSCLC CSCs than EGFR wild-type NSCLC CSCs. Both compounds suppressed the self-renewal ability of NSCLC CSCs and NSCLC-CSC-derived tumor growth in vivo. Furthermore, C9 and CsA inhibited NSCLC CSC growth by activating the intrinsic apoptotic pathway. Notably, C9 and CsA reduced the expression levels of major CSC markers, including integrin α6, CD133, CD44, ALDH1A1, Nanog, Oct4, and Sox2, through dual downregulation of the CypA/CD147 axis and EGFR activity in NSCLC CSCs. Our results also show that the EGFR tyrosine kinase inhibitor afatinib inactivated EGFR and decreased the expression levels of CypA and CD147 in NSCLC CSCs, suggesting close crosstalk between the CypA/CD147 and EGFR pathways in regulating NSCLC CSC growth. In addition, combined treatment with afatinib and C9 or CsA more potently inhibited the growth of EGFR-mutant NSCLC CSCs than single-compound treatments. These findings suggest that the natural CypA inhibitors C9 and CsA are potential anticancer agents that suppress the growth of EGFR-mutant NSCLC CSCs, either as monotherapy or in combination with afatinib, by interfering with the crosstalk between CypA/CD147 and EGFR. [ABSTRACT FROM AUTHOR]

Introduction: Airway epithelial mitochondrial injury is an important pathogenesis of chronic obstructive pulmonary disease (COPD). Cyclophilin D (CypD) is a component of mitochondrial permeability transition pore and related to mitochondrial damage. However, the role of CypD in airway epithelial mitochondrial injury and COPD pathogenesis remains unclear. Methods: CypD expression in human airway epithelium was determined by immunohistochemistry, and mitochondrial structure of airway epithelial cell was observed under the transmission electron microscopy. The expression of CypD signaling pathway in cigarette smoke extract (CSE)-treated airway epithelial cells was measured by real-time PCR and Western-blot. CSE-induced damage of airway epithelial cell and mitochondria was further studied. Results: Immunohistochemistry and transmission electron microscopy analysis revealed that CypD expression in airway epithelium was significantly increased associated with notable airway epithelial mitochondrial structure damage in the patients with COPD. The mRNA and protein expression of CypD was significantly increased in concentration- and time-dependent manners when airway epithelial cells were treated with CSE. CypD siRNA pretreatment significantly suppressed the increases of CypD and Bax expression, and reduced the decline of Bcl-2 expression in 7.5% CSE-treated airway epithelial cells. Furthermore, CypD silencing significantly attenuated mitochondrial damage and cell apoptosis, and increased cell viability when airway epithelial cells were stimulated with 7.5% CSE. Conclusion: These data suggest that CypD signaling pathway is involved in the pathogenesis of COPD and provide a potential therapeutic target for COPD. [ABSTRACT FROM AUTHOR]

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Cyclophilin (CYP) plays an important role in plant response to stress, and OsCYP2, one gene of cyclophlilin family, is involved in auxin signal transduction and stress signaling in rice. However, the mechanism that OsCYP2 is involved in rice response to low temperature is still unclear. We identified a new OsCYP2 allelic mutant, lrl3, with fewer lateral roots, and the differences in shoot height, primary root length and adventitious root length increased with the growth process compared to the wild-type plant. Auxin signaling pathway was also affected and became insensitive to gravity. The transgenic rice plants with over-expression of OsCYP2 were more tolerant to low temperature than the wild-type plants, suggesting that OsCYP2 was involved in the low temperature response in rice. In addition, OsCYP2 negatively regulated the expression of OsTPS38, a terpene synthase gene, and was dependent on the OsCDPK7-mediated pathway in response to low temperature stress. OsTPS38-overexpressed transgenic line ox-2 was more sensitive to low temperature. Therefore, OsCYP2 may negatively regulate OsTPS38 through an OsCDPK7-dependent pathway to mediate the response to low temperature in rice. These results provide a new basis for auxin signaling genes to regulate rice response to low temperature stress. [ABSTRACT FROM AUTHOR]

Adoptive T-cell therapy (ACT) is successfully applied in cancer treatment; however, its efficiency can be limited by a low viability, short persistence time, and loss of functional activity of T-cells after adoptive transfer. The search for novel immunomodulators that can improve the viability, expansion, and functions of T-cells after their infusion with the minimal side effects could contribute to the development of more efficient and safe ACT strategies. Recombinant human cyclophilin A (rhCypA) is of particular interest in this respect, as it exhibits pleiotropic immunomodulatory activity and stimulates both innate and adaptive anti-tumor immunity. Here, we evaluated the effect of rhCypA on the efficacy of ACT in the mouse EL4 lymphoma model. Lymphocytes from transgenic 1D1a mice with an inborn pool of EL4-specific T-cells were used as a source of tumor-specific T-cells for ACT. In models of immunocompetent and immunodeficient transgenic mice, the course (3 days) rhCypA administration was shown to significantly stimulate EL4 rejection and prolong the overall survival of tumor-bearing mice after adoptive transfer of lowered doses of transgenic 1D1a cells. Our studies showed that rhCypA significantly improved the efficacy of ACT by enhancing the effector functions of tumor-specific cytotoxic T-cells. These findings open up the prospects for the development of innovative strategies of adoptive T-cell immunotherapy for cancer using rhCypA as an alternative to existing cytokine therapies. [ABSTRACT FROM AUTHOR]