FK506 binding proteins and inflammation related signalling pathways; basic biology, current status and future prospects for pharmacological intervention

FKBP5 mediates glucocorticoid signaling in estrogen deficiency-associated endothelial dysfunction

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of mortality among postmenopausal women, with atherosclerosis being a major underlying factor. Endothelial dysfunction, a key initiating event in atherosclerosis, can be triggered by hormonal and metabolic changes. While estrogen deficiency has been linked to increased cardiovascular risk, the molecular mechanisms by which it exacerbates endothelial dysfunction, particularly in the presence of elevated glucocorticoid levels, remain poorly understood. This study aims to explore the role of FK506-binding protein 5 (FKBP5) in mediating glucocorticoid-induced endothelial dysfunction in estrogen-deficient females.

METHODS

Estrogen deficiency was developed in female mice by ovariectomy (OVX). Female mice and human umbilical vein endothelial cells (HUVECs) were treated with dexamethasone (DEX) to mimic elevated cortisol levels in vivo and vitro. Endothelial function of the mice aorta was assessed using wire myography. Oxidative stress and inflammation were evaluated through reactive oxygen species (ROS) detection, immunofluorescence and mRNA expression analysis. The selective FKBP5 inhibitor SAFit2 was used to study the functional role of FKBP5 in these processes.

RESULTS

Estrogen deficiency contributed to endothelial dysfunction in female mice, an effect exacerbated by elevated glucocorticoid levels. FKBP5 expression was upregulated in both ovariectomized mice aortas and DEX-treated endothelial cells. Inhibition of FKBP5 reversed endothelial dysfunction, reduced ROS levels, and suppressed the expression of pro-inflammatory mediators, including ICAM-1, IL-1β, TNF-α, and NF-κB.

CONCLUSION

FKBP5 mediates glucocorticoid-induced endothelial dysfunction under estrogen-deficient conditions. Inhibition of FKBP5 represents a promising therapeutic strategy to ameliorate endothelial dysfunction and improve vascular health in estrogen-deficient women.

Species-specific in vivo exposure assessment and in vivo-in vitro correlation of the carboxylate esters prodrug HD56 targeting FK506 binding proteins: The pivotal role of humanized mice

HD561, which was designed to enhance nerve growth, was re-engineered into HD56, a carboxylic acid ester prodrug. The goal of this study was to compare the druggability, species differences, and the correlation between in vitro and in vivo transformation of HD56 to HD561 from a pharmacokinetic (PK) perspective, offering a scientific basis for HD56's clinical research. The bidirectional transmembrane transport of HD56 and HD561 was investigated using Caco-2 cells and LLC-PK1 cells overexpressing MDR1 monolayer cells. Recombinant enzymes and chemical inhibition methods were employed to identify the reaction phenotyping. The conversion of HD56 to HD561 was compared in hepatic and intestinal microsomes, as well as plasma, across different species, including humans, rats, monkeys, and mice with humanized liver. PK studies were conducted in rats, monkeys, and mice with different humanized liver proportions (Hu-URG, Hu-URG-Low, and Hu-URG-High). Finally, an in vivo-in vitro correlation was established between the conversion rate of HD56 to HD561. Results showed that HD56 had better permeability than HD561. HD56 could be hydrolyzed by carboxylesterase 1 to HD561 and be metabolized by cytochrome P450 isoenzymes, while HD561 underwent further metabolism via CYP2C9. Significant species differences existed, and a good in vivo-in vitro correlation was only achieved in humanized mice (r = 0.98). Both in vitro and in vivo PK characteristics of HD56 were remarkably superior to those of HD561, suggesting that HD56 held promise for development. Humanized liver mice serve as a powerful model to address the issue of species differences in ester prodrugs. SIGNIFICANCE STATEMENT: Prodrug HD56 showed superior pharmacokinetic properties compared with the active compound HD561, guiding similar prodrug research. The use of chimeric mice with human hepatocytes, for the first time, to study carboxylesterase (CES) prodrug HD56 provides a model that closely mimics human metabolism. Findings deepen understanding of HD56's behavior and offer a predictive tool for CES prodrugs' metabolic fate, streamlining drug development and improving preclinical accuracy.

Potential roles of inhalation aromatherapy on stress-induced depression by inhibiting inflammation in the peripheral olfactory system

According to principles of Traditional Chinese Medicine, the nose is the passage for exogenous evil to invade the body, while essential or volatile oils extracted from herbs have the effects of dispelling melancholy, repelling foulness, and resuscitation with aromatics. Inhalation aromatherapy can target the brain and has a potential therapeutic effect on mood disorders. However, in particular, the mechanism of the effect of inhalation aromatherapy on the olfactory mucosa (OM) of the nasal cavity at the peripheral level, the first step in olfactory detection, where olfactory sensory neurons (OSNs) relay information to brain for signal processing, remains unclear. Here, we examined the roles of inhalation aromatherapy with compound essential oils derived from Bergamot, Peppermint and Rosa rugose on chronic unpredictable mild stress (CUMS)-induced depression and explored potential therapeutic targets in the peripheral OM. We found that inhalation aromatherapy effectively ameliorated CUMS-induced depression and olfactory dysfunction in rats. Strikingly, inhalation aromatherapy improved pathological changes, significantly reduced apoptosis levels, and promoted olfactory neurogenesis in the OM, which may contribute to the beneficial effects on the olfactory function of depressed rats. Further, inhalation aromatherapy significantly may reverse inflammation levels in the OM through Sirt1/FKBP5/GR/NF-κB signaling pathway, and prevented neuroinflammation in other parts of the olfactory system such as the hippocampus and prefrontal cortex, which may play a role in the olfactory impairments in rats with depression. Collectively, we have demonstrated that inhalation aromatherapy could efficiently prevent the local inflammatory responses in the OM of CUMS depression model rats. These findings provide new insights into the treatment of depression with aromatherapy, as well as new concept for the identification of novel antidepressant strategies.

In silico identification of novel ligands targeting stress-related human FKBP5 protein in mental disorders

FK506-binding protein 51 (FKBP51 or FKBP5) serves as a crucial stress modulator implicated in mental disorders, presenting a potential target for intervention. Inhibitors like SAFit2, rapamycin, and tacrolimus exhibit promising interactions with this protein. Despite these advances, challenges persist in diversifying FKBP5 ligands, prompting further exploration of interaction partners. Hence, this study aims to identify other potential ligands. Employing molecular docking, we generated complexes with various ligands (rapamycin, tacrolimus, SAFit2-Selective antagonist of FKBP51 by induced fit, ascomycin, pimecrolimus, rosavin, salidroside, curcumin, apigenin, uvaricin, ruscogenin, neoruscogenin, pumicalagin, castalagin, and grandinin). We identified the top 3 best ligands, of which ruscogenin and neoruscogenin had notable abilities to cross the blood-brain barrier and have high gastrointestinal absorption, like curcumin. Toxicity predictions show ruscogenin and neoruscogenin to be the least toxic based on oral toxicity classification (Class VI). Tyrosine (Tyr113) formed consistent interactions with all ligands in the complex, reinforcing their potential and involvement in stress modulation. Molecular dynamic (MD) simulation validated strong interactions between our three key ligands and FKBP5 protein and provided an understanding of the stability of the complex. The binding free energy (ΔG) of the best ligands (based on pharmacological properties) from MD simulation analysis is -31.78 kcal/mol for neoruscogenin, -30.41 kcal/mol for ruscogenin, and -27.6 kcal/mol for curcumin. These molecules, therefore, can serve as therapeutic molecules or biomarkers for research in stress-impacted mental disorders. While offering therapeutic implications for mental disorders by attenuating stress impact, it is crucial to emphasize that these ligands' transition to clinical applications necessitates extensive experimental research, including clinical trials, to unravel the intricate molecular and neural pathways involved in these interactions.

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.

FK506-binding proteins: Emerging target and therapeutic opportunity in multiple tumors

The FK506-binding protein (FKBP) family plays a key role in a variety of tumors and is involved in the regulation of important signaling pathways including AKT, NF-κB and p53, which affects cell proliferation, migration, and multiple cell death modes. Here, we summarize the findings that different FKBP family members exhibit dual functions of promoting or inhibiting tumorigenesis in different types of tumors. The expression levels of FKBP family members are closely related to the prognosis of patients, thus might be used as potential diagnostic and prognostic biomarkers. In the future, it is necessary to combine single-cell sequencing to resolve the spatial distribution of FKBP isoforms, develop clinical validation to promote the translation from molecular mechanism to precision therapy.

Distinct single-cell transcriptional profile in CD4+ T-lymphocytes among obese children with asthma

Obesity is a risk factor for asthma morbidity, associated with less responsiveness to inhaled corticosteroids. CD4+ T cells are central to the immunology of asthma and may contribute to the unique obese asthma phenotype. We sought to characterize the single-cell CD4+ transcriptional profile differences in obese children with asthma compared with normal-weight children with asthma. Eight normal-weight and obese participants with asthma were clinically phenotyped and matched based on asthma control. Peripheral blood (PB) CD4+ T cells were sorted, and single-cell RNA sequencing was conducted. Cell clusters were identified by canonical gene expression and differential gene expression and reactome pathway analysis was applied. The obese PB bulk transcriptomic signature from the U-BIOPRED pediatric cohort was assessed in our cohort as well. Obese children with asthma have a distinct CD4+ transcriptional profile with differential gene expression. There were more activated protein tyrosine phosphate receptor type C (PTPRC)high cells and less PTPRClow in children with obesity. Children with obesity had higher enrichment of the neutrophil degranulation, interleukin-7 (IL-7) receptor, and IL-7-related janus kinase-signal transducer and activator of transcription signaling pathways. Genes previously associated with more severe asthma, IL-32, FKBP5 gene expression, IL-6, and Rho transcriptional signaling, were also enriched in obese children with asthma. Our findings shed insight into the molecular mechanisms underpinning more severe and steroid-resistant asthma among children with obesity. Further investigation is needed to identify potential new therapeutic targets for this group.NEW & NOTEWORTHY This study identified unique contributors to asthma in children with obesity and found novel pathways. Increased expression of IL-7R, IL-32, PARP-1, FKBP5 gene, IL-6, and Rho transcriptional signaling were observed in obese individuals with asthma.

Chaihu Shugan San Exerts Antidepressant Effects by Regulating Glucocorticoid Metabolism in CUMS Rats and Network Pharmacology Provides Complementary Mechanistic Insights

Traditional Chinese medicine Chaihu Shugan San (CSGS) is a classic Chinese herb prescription for improving depression, but its specific molecular mechanism has not been fully clarified. This study integrates network pharmacology and experimental validation to investigate CSGS's antidepressant effects, focusing on its impact on GC metabolism and related pathways. In this research, the antidepressant mechanism of CSGS in relation to the depression model induced by chronic unpredictable mild stress will be discussed. High-performance liquid tandem mass spectrometry was applied for the verification of the grown metabolites' economic vitality in rat plasma and the prefrontal cortex. The revelation of behavioral test results showed that the administration of CSGS improved depression symptoms significantly at the end of the administration period, which was 8 weeks. Network pharmacology was used to assist in verifying and improving the mechanism by which the active ingredients of CSGS affect the glucocorticoid metabolic pathway to exert antidepressant effects. CSGS significantly improved glucocorticoid (GC) metabolism by reducing corticosterone (CORT) levels and increasing dehydrocorticosterone (11-DHCORT) and the 11-DHCORT/CORT ratio in plasma and PFC. It regulated GC metabolism in the liver and PFC by downregulating GC synthase (11β-HSD1) and upregulating GC metabolic enzymes (11β-HSD2). Additionally, CSGS restored GC signaling by upregulating GR and HSP-90α, downregulating FKBP51 and HSP-70, and alleviating inflammation by inhibiting NF-κB P65 and HAT expression. These effects, particularly in the liver and PFC, were stronger than those with fluoxetine. Network pharmacology revealed that CSGS targets multiple pathways including PI3K-Akt, FoxO, HIF-1, and mTOR. These results indicate that CSGS can improve the depressive state of rats by regulating glucocorticoid metabolism and other related pathways as well as downstream signaling proteins.

Baicalin alleviates lipid metabolism disorders in diabetic kidney disease via targeting FKBP51

BACKGROUND

Diabetic kidney disease (DKD) represents the primary aetiological factor in end-stage renal disease, wherein lipid metabolism disorders contribute to the progression of DKD. Baicalin, a composition from Scutellaria baicalensis, has exhibited the potential to mitigate lipid metabolism disorders of DKD, but the precise mechanisms remain unclear.

METHODS

High-fat-diet (HFD)/streptozotocin (STZ)-induced DKD mouse model was established to appraise the effects of baicalin on renal function, dyslipidemia, and renal ectopic lipid deposition. The effects of baicalin on lipid accumulation in vitro were assessed in tubular epithelial cells derived from mice (TCMK-1) treated with palmitic acid (PA). The potential targets of baicalin were identified by drug affinity responsive target stability (DARTS) -LC/MS. The impact of the identified target on lipid metabolism was elucidated in TCMK-1 cells through both knockdown and overexpression experiments.

RESULTS

The findings indicated that baicalin effectively mitigated dyslipidemia and renal ectopic lipid deposition in the HFD/STZ-induced DKD mouse model. FK506-binding protein 51(FKBP51) was identified as an endogenous target of baicalin, with the Tyr113 residue playing a crucial role in the binding interaction. Additionally, FKBP51 knockdown brought about intracellular lipid accumulation, but FKBP51 overexpression was found to effectively counteract the lipid accumulation induced by PA. Further investigation revealed that FKBP51 regulates lipid accumulation through the Tyr113 residue. Notably, the lipid-lowering effect of baicalin was diminished following FKBP51 knockdown.

CONCLUSION

This study first identifies that FKBP51 is beneficial for lipid metabolism homeostasis in DKD and suggests baicalin as an effective molecule for targeting FKBP51 in the treatment of lipid metabolism disorders associated with DKD.

Multi-omics elucidates the kidney damage caused by aquatic Cu via the gut-kidney axis in ducks

Copper (Cu) is an essential trace element for biological growth and development. Excessive intake of Cu exists harmful effects on organisms. However, whether excessive Cu intake induces kidney function damage by gut microbiota regulation remains unclear. Ducks are important species of waterfowl that are often exposed to Cu contamination in water sources. In this study, we aim to elucidate the effects of Cu exposure on renal inflammation through the gut-kidney axis in ducks. The ducks were gavaged with different doses of CuSO4 (0, 100, and 200 mg/kg body weight) for 4 weeks. Results indicate that Cu exposure causes pathological damage to the kidney, with a significant increase in the levels of TNFα, IL-6, and IL-1β in both serum and renal tissue. 16S rDNA analysis revealed that the relative abundances of Candidatus_Saccharimonas and Bacteroides were significantly reduced in the Cu-induced group. Transcriptomic analysis of kidney tissue reveals that following Cu exposure, 30 genes show significant differential expression. GO and KEGG enrichment analyses were most involved in Interleukin-1 Receptor Activity, Taurine and hypotaurine metabolism, Nitrogen metabolism, and Proximal tubule bicarbonate reclamation. Metabolomic analysis revealed that 28 metabolites are present in both kidney tissue and cecal contents. Correlation analysis revealed a strong correlation among 5 common metabolites: Aminoglutethimide, Boscalid, Dantrolene, Cer[ns] d34:1, and Stearidonic acid. In the cecum, these five metabolites are closely associated with 26 intestinal microorganisms, including Bacteroides, Candidatus_Saccharimonas, and Colidextribacter. In the kidney, apart from Stearidonic acid, the other four metabolites are closely correlated with genes such as FOS, and IL1RL1. Overall, our study indicates that excessive Cu induces significant kidney inflammation, the metabolites alteration and gut microbiota disorders. These findings shed light on the underlying mechanisms of Cu-induced kidney damage via the indirect pathway of the gut-kidney axis.

Enhanced ovarian FKBP51 expression is associated with ovarian aging: a molecular insight for age-related fertility in women

OBJECTIVE

To study the relationship between FK506-binding protein 51 (FKBP51) and ovarian aging and/or diminished ovarian reserve (DOR) in human ovaries by comparing FKBP51 levels in granulosa cells (GCs) and cumulus cells (CCs), collected during controlled ovarian stimulation (COS) from women of advanced reproductive age and/or with a diagnosis of DOR with that of young women with normal ovarian reserve. To explore the association between increased FKBP51 expression and human ovarian aging further, expression of FKBP51 was compared in ovarian stroma of postmenopausal vs. premenopausal women. Lastly, this relation was further queried by comparing ovarian expression of several collagen genes as markers of ovarian fibrosis in 14-month-old wild-type (Fkbp5+/+) and Fkbp5 knockout (Fkbp5-/-) mice.

DESIGN

Laboratory-based experimental study.

SUBJECTS

Samples collected included follicular fluid, CCs, GCs, and serum from group 1: young women with normal ovarian reserve (<35 years; n = 12); group 2: DOR (antimüllerian hormone <1 ng/mL; n = 10); and group 3: women of advanced age with normal ovarian reserve (>37 years; n = 8). Ovarian stromal tissues obtained from surgical specimen of post-menopausal (50-65 years; n = 6) and pre-menopausal (18-30 years; n = 6). Ovarian tissues from 14-month-old Fkbp5+/+and Fkbp5-/- mice. All the experiments were performed at an academic-affiliated assisted reproductive technology unit/laboratory.

EXPOSURE

Comparison of FKBP51 expression in GCs and CCs from women undergoing COS, ovarian stromal tissue from pre- and post-menopausal women, and ovarian tissue from aged Fkbp5+/+and Fkbp5-/- mice.

MAIN OUTCOME MEASURES

(1) Level of FKBP51 in human GCs and CCs, collected during COS by performing real-time quantitative polymerase chain reaction (qPCR). (2) Immunohistochemistry to detect FKBP51 levels and Picrosirius Red staining to detect collagen deposition in human ovarian stromal tissue. (3) Real-time qPCR to compare expression levels of several collagen genes in Fkbp5+/+ and Fkbp5-/- old mice ovaries. Serum and follicular fluid levels of transforming growth factor β1, and soluble endoglin measured by enzyme-linked immunosorbent assay.

RESULTS

Immunohistochemistry revealed that FKBP51 histologic score levels in ovarian stromal tissue were significantly higher in postmenopausal vs. premenopausal women (mean ± SEM, 160.52 ± 17.75 vs. 120.67 ± 14.33; P=.002). Stronger Picrosirius Red staining, suggestive of fibrosis, was seen in ovarian stromal tissue of postmenopausal vs. premenopausal women (54.06 ± 6.94 vs. 37.50 ± 14.29; P=.02). Analysis of qPCR revealed that (1) Col1a1, Col1a2, Col3a1 levels were significantly lower in ovaries obtained from 14-month-old Fkbp5-/- vs. Fkbp5+/+ mice; (2) FKBP5 levels significantly increased in CCs of advanced age women vs. younger women (1.71 ± 0.22 vs. 1.11 ± 0.15; P=.03); and (3) FKBP5 levels were approximately threefold higher in GCs of women with DOR vs. age-matched control (3.22 ± 1.11 vs. 1.30 ± 0.54; P=.03).

CONCLUSION

This study for the first time demonstrates expression profile of FKBP51 in human ovary and its potential role in ovarian aging. Our results indicate that the up-regulation of FKBP51 is associated with ovarian aging. Moreover, in women undergoing in vitro fertilization treatment, enhanced FKBP51 expression is seen in those with DOR or women of advanced maternal reproductive age, who have poor prognosis. Therefore, drugs targeting inhibition of FKBP51 expression and/or activity may delay ovarian aging or treat premature ovarian aging.

The Role of HSP90 Molecular Chaperones in Depression: Potential Mechanisms

Major depressive disorder (MDD) is characterized by high rates of disability and death and has become a public health problem that threatens human life and health worldwide. HPA axis disorder and neuroinflammation are two common biological abnormalities in MDD patients. Hsp90 is an important molecular chaperone that is widely distributed in the organism. Hsp90 binds to the co-chaperone and goes through a molecular chaperone cycle to complete its regulation of the client protein. Numerous studies have demonstrated that Hsp90 regulates how the HPA axis reacts to stress and how GR, the HPA axis' responsive substrate, matures. In addition, Hsp90 exhibits pro-inflammatory effects that are closely related to neuroinflammation in MDD. Currently, Hsp90 inhibitors have made some progress in the treatment of a variety of human diseases, but they still need to be improved. Further insight into the role of Hsp90 in MDD provides new ideas for the development of new antidepressant drugs targeting Hsp90.

Tacrolimus: Physicochemical stability challenges, analytical methods, and new formulations

Tacrolimus, a potent immunosuppressant, is widely used in several formulations to treat organ rejection in transplant patients. However, its physicochemical stability poses significant challenges, including thermal instability, photostability issues, low solubility, and drug-excipient incompatibility. This review article focuses on the details of these challenges and discusses the analytical methods employed to study tacrolimus stability, such as thermal, spectroscopic, and chromatographic methods in different formulations. New formulations to enhance tacrolimus stability are explored, including lipid-based nanocarriers, polymers, and thin film freezing. Researchers and formulators can optimize tacrolimus formulations to improve efficacy and patient outcomes by understanding and addressing these stability challenges.

Mitochondrial-nuclear communication by FKBP51 shuttling

The HSP90-binding immunophilin FKBP51 is a soluble protein that shows high homology and structural similarity with FKBP52. Both immunophilins are functionally divergent and often show antagonistic actions. They were first described in steroid receptor complexes, their exchange in the complex being the earliest known event in steroid receptor activation upon ligand binding. In addition to steroid-related events, several pleiotropic actions of FKBP51 have emerged during the last years, ranging from cell differentiation and apoptosis to metabolic and psychiatric disorders. On the other hand, mitochondria play vital cellular roles in maintaining energy homeostasis, responding to stress conditions, and affecting cell cycle regulation, calcium signaling, redox homeostasis, and so forth. This is achieved by proteins that are encoded in both the nuclear genome and mitochondrial genes. This implies active nuclear-mitochondrial communication to maintain cell homeostasis. Such communication involves factors that regulate nuclear and mitochondrial gene expression affecting the synthesis and recruitment of mitochondrial and nonmitochondrial proteins, and/or changes in the functional state of the mitochondria itself, which enable mitochondria to recover from stress. FKBP51 has emerged as a serious candidate to participate in these regulatory roles since it has been unexpectedly found in mitochondria showing antiapoptotic effects. Such localization involves the tetratricopeptide repeats domains of the immunophilin and not its intrinsic enzymatic activity of peptidylprolyl-isomerase. Importantly, FKBP51 abandons the mitochondria and accumulates in the nucleus upon cell differentiation or during the onset of stress. Nuclear FKBP51 enhances the enzymatic activity of telomerase. The mitochondrial-nuclear trafficking is reversible, and certain situations such as viral infections promote the opposite trafficking, that is, FKBP51 abandons the nucleus and accumulates in mitochondria. In this article, we review the latest findings related to the mitochondrial-nuclear communication mediated by FKBP51 and speculate about the possible implications of this phenomenon.

Necroptosis and autophagy in cisplatinum-triggered nephrotoxicity: Novel insights regarding their prognostic and diagnostic potential

Necroptosis is an innovative class of programmed autophagy (Atg) and necrosis; considered as a type of homeostatic housekeeping machinery that have observed an escalating concern due to its power in alleviating Cisplatinum-induced nephrotoxicity. This article elucidated in details the prospective role of both autophagy and necroptosis on Cisplatinum-triggered nephrotoxicity and investigating more potent therapy via lactoferrin and Ti-NPS conjugation. Cisplatinum is a commonly used chemotherapeutic drug; one of the limiting adverse actions of cisplatinum is renal toxicity. Upon cisplatinum administration, autophagy is highly stimulated in the kidney to shield against nephrotoxicity. Atg is a lysosomal degradation process which discards detorirated proteins to retain cell homeostasis. This article summarizes necroptosis progress in reconizing cisplatinum nephrotoxicity and debates how this progress can help in discovering more potent therapy via lactoferrin and Ti-NPS conjugation via monitoring autophagy and apoptotic biomarkers X-box-binding protein 1 (XBP), C/EBP homologous protein (CHOP), hypoxanthine phosphoribosyltransferase-1 (HPRT), FKBP prolyl isomerase 1B (FKBP), Cellular myelocytomatosis oncogene (C-myc), tumor suppressor gene (P53) and tumor necrosis factor (TNF-α). Cisplatinum nephrotoxicity was conducted in rat model via an oral dose of (2 mg/kg BW) for one month furthermore a comparative study was conducted among TiNPs-loaded Cisplatinum and Lactoferrin loaded Cisplatinum. Loaded drug delivery system counteracted Cisplatinum triggered nephrotoxicity via controlling autophagy and apoptotic XBP, CHOP, HPRT, FKBP, C-myc, P53 and TNF-α signaling pathway.

Differential Dynamics and Roles of FKBP51 Isoforms and Their Implications for Targeted Therapies

The expression of FKBP5, and its resulting protein FKBP51, is strongly induced by glucocorticoids. Numerous studies have explored their involvement in a plethora of cellular processes and diseases. There is, however, a lack of knowledge on the role of the different RNA splicing variants and the two protein isoforms, one missing functional C-terminal motifs. In this study, we use in vitro models (HeLa and Jurkat cells) as well as peripheral blood cells of a human cohort (N = 26 male healthy controls) to show that the two expressed variants are both dynamically upregulated following dexamethasone, with significantly earlier increases (starting 1-2 h after stimulation) in the short isoform both in vitro and in vivo. Protein degradation assays in vitro showed a reduced half-life (4 h vs. 8 h) of the shorter isoform. Only the shorter isoform showed a subnuclear cellular localization. The two isoforms also differed in their effects on known downstream cellular pathways, including glucocorticoid receptor function, macroautophagy, immune activation, and DNA methylation regulation. The results shed light on the difference between the two variants and highlight the importance of differential analyses in future studies with implications for targeted drug design.

In Vitro Safety Study on the Use of Cold Atmospheric Plasma in the Upper Respiratory Tract

Cold atmospheric plasma (CAP) devices generate reactive oxygen and nitrogen species, have antimicrobial and antiviral properties, but also affect the molecular and cellular mechanisms of eukaryotic cells. The aim of this study is to investigate CAP treatment in the upper respiratory tract (URT) to reduce the incidence of ventilator-associated bacterial pneumonia (especially superinfections with multi-resistant pathogens) or viral infections (e.g., COVID-19). For this purpose, the surface-microdischarge-based plasma intensive care (PIC) device was developed by terraplasma medical GmbH. This study analyzes the safety aspects using in vitro assays and molecular characterization of human oral keratinocytes (hOK), human bronchial-tracheal epithelial cells (hBTE), and human lung fibroblasts (hLF). A 5 min CAP treatment with the PIC device at the "throat" and "subglottis" positions in the URT model did not show any significant differences from the untreated control (ctrl.) and the corresponding pressurized air (PA) treatment in terms of cell morphology, viability, apoptosis, DNA damage, and migration. However, pro-inflammatory cytokines (MCP-1, IL-6, and TNFα) were induced in hBTE and hOK cells and profibrotic molecules (collagen-I, FKBP10, and αSMA) in hLF at the mRNA level. The use of CAP in the oropharynx may make an important contribution to the recovery of intensive care patients. The results indicate that a 5 min CAP treatment in the URT with the PIC device does not cause any cell damage. The extent to which immune cell activation is induced and whether it has long-term effects on the organism need to be carefully examined in follow-up studies in vivo.

Network analysis and experimental verification of Salvia miltiorrhiza Bunge-Reynoutria japonica Houtt. drug pair in the treatment of non-alcoholic fatty liver disease

CONTEXT

There are currently no approved specific clinical drugs for non-alcoholic fatty liver disease (NAFLD). Salvia miltiorrhiza Bunge-Reynoutria japonica Houtt. drug pair (SRDP) has been widely used in the treatment of chronic liver diseases. However, the mechanism of SRDP treating NAFLD remains unclear.

OBJECTIVE

Based on network analysis and in vitro experimental verification, we investigated the effect of SRDP on lipid deposition and explored its possible mechanism for the treatment of NAFLD.

METHODS

The TCMSP platform was used to screen the active metabolites of SRDP and corresponding targets. The GeneCards and OMIM databases were used to screen the NAFLD targets. The drug-disease intersecting targets were extracted to obtain the potential targets. Then the protein-protein interaction (PPI) and drug-active metabolites-target-disease network map was constructed. The DAVID database was performed to GO and KEGG pathway enrichment analysis for the intersecting targets. The core active metabolite and signaling pathway were verified by in vitro experiments.

RESULTS

Network analysis predicted 59 active metabolites and 89 targets of SRDP for the treatment of NAFLD. 112 signaling pathways were enriched for KEGG pathways, including PI3K-AKT signaling pathway,etc. It was confirmed that luteolin, the core active metabolite of SRDP, effectively reduced fat accumulation and intracellular triglyceride content in HepG2 fatty liver cell model. Luteolin could inhibit mTOR pathway by inhibiting PI3K-AKT signaling pathway phosphorylation, thereby activating autophagy to alleviate NAFLD. DISCUSSION AND CONCLUSION: The results of this study validate and predict the possible role of various active metabolites of SRDP in the treatment of NAFLD through multiple targets and signaling pathways. The core active metabolite of SRDP, luteolin can alleviate NAFLD by acting on the PI3K-AKT-mTOR signaling pathway to induce autophagy.

Overexpressed FKBP5 mediates colorectal cancer progression and sensitivity to FK506 treatment via the NF-κB signaling pathway

Colorectal cancer (CRC) is a common and deadly tumor. FK506-binding protein 5 (FKBP5) is associated with some cancers, but the role of FKBP5 in CRC is not clear. The present study aimed to reveal the relationship between FKBP5 and CRC and to uncover the roles of FK506 in CRC. In total, 96 CRC patients were recruited. Survival analysis was conducted using the Kaplan-Meier method and COX regression analyses. Bioinformatics analyses were performed to explore the functions of FKBP5. The mechanisms of FKBP5 and the roles of FK506 in CRC progression were clarified by immunohistochemistry, MTS, scratch assay, transwell and flow cytometric analyses via in vitro and in vivo experiments. FKBP5 was overexpressed in 77 cancer tissues compared to that in matched normal tissues, and the overall survival rate of these patients was relatively shorter. Bioinformatics analyses showed that FKBP5 regulates proliferation, invasion, migration, epithelial-mesenchymal transition and nuclear factor-kappa B (NF-κB) signaling. The upregulation or downregulation of FKBP5 dramatically increases or decreases the proliferation, invasion and migration abilities of CRC cells. The expression of NF-κB, inhibitor B kinase α, matrix metalloproteinase-2 and metalloproteinase-9 positively correlated with FKBP5. FK506 inhibits the progression of CRC via the FKBP5/NF-κB signaling pathway. Our study identified a regulatory role for FKBP5 in CRC progression. Therefore, targeting FKBP5 may provide a novel treatment approach for CRC. FK506 can inhibit the progression of CRC by restraining the FKBP5/NF-κB signaling pathway and is expected to become a new drug for the treatment of CRC.

SPI1 activates TGF-β1/PI3K/Akt signaling through transcriptional upregulation of FKBP12 to support the mesenchymal phenotype of glioma stem cells

Glioma stem cells (GSCs) exhibit diverse molecular subtypes with the mesenchymal (MES) population representing the most malignant variant. The oncogenic potential of Salmonella pathogenicity island 1 (SPI1), an oncogenic transcription factor, has been established across various human malignancies. In this study, we explored the association between the SPI1 pathway and the MES GSC phenotype. Through comprehensive analysis of the Cancer Genome Atlas and Chinese Glioma Genome Atlas glioma databases, along with patient-derived GSC cultures, we analyzed SPI1 expression. Using genetic knockdown and overexpression techniques, we assessed the functional impact of SPI1 on GSC MES marker expression, invasion, proliferation, self-renewal, and sensitivity to radiation in vitro, as well as its influence on tumor formation in vivo. Additionally, we investigated the downstream signaling cascades activated by SPI1. Our findings revealed a positive correlation between elevated SPI1 expression and the MES phenotype, which in turn, correlated with poor survival. SPI1 enhanced GSC MES differentiation, self-renewal, and radioresistance in vitro, promoting tumorigenicity in vivo. Mechanistically, SPI1 augmented the transcriptional activity of both TGF-β1 and FKBP12 while activating the non-canonical PI3K/Akt pathway. Notably, inhibition of TGF-β1/PI3K/Akt signaling partially attenuated SPI1-induced GSC MES differentiation and its associated malignant phenotype. Collectively, our results underscore SPI1's role in activating TGF-β1/PI3K/Akt signaling through transcriptional upregulation of FKBP12, thereby supporting the aggressive MES phenotype of GSCs. Therefore, SPI1 emerges as a potential therapeutic target in glioma treatment.

The high FKBP1A expression in WBCs as a potential screening biomarker for pancreatic cancer

Given the limitation of current routine approaches for pancreatic cancer screening and detection, the mortality rate of pancreatic cancer cases is still critical. The development of blood-based molecular biomarkers for pancreatic cancer screening and early detection which provide less-invasive, high-sensitivity, and cost-effective, is urgently needed. The goal of this study is to identify and validate the potential molecular biomarkers in white blood cells (WBCs) of pancreatic cancer patients. Gene expression profiles of pancreatic cancer patients from NCBI GEO database were analyzed by CU-DREAM. Then, mRNA expression levels of three candidate genes were determined by quantitative RT-PCR in WBCs of pancreatic cancer patients (N = 27) and healthy controls (N = 51). ROC analysis was performed to assess the performance of each candidate gene. A total of 29 upregulated genes were identified and three selected genes were performed gene expression analysis. Our results revealed high mRNA expression levels in WBCs of pancreatic cancer patients in all selected genes, including FKBP1A (p < 0.0001), PLD1 (p < 0.0001), and PSMA4 (p = 0.0002). Among candidate genes, FKBP1A mRNA expression level was remarkably increased in the pancreatic cancer samples and also in the early stage (p < 0.0001). Moreover, FKBP1A showed the greatest performance to discriminate patients with pancreatic cancer from healthy individuals than other genes with the 88.9% sensitivity, 84.3% specificity, and 90.1% accuracy. Our findings demonstrated that the alteration of FKBP1A gene in WBCs serves as a novel valuable biomarker for patients with pancreatic cancer. Detection of FKBP1A mRNA expression level in circulating WBCs, providing high-sensitive, less-invasive, and cost-effective, is simple and feasible for routine clinical setting that can be applied for pancreatic cancer screening and early detection.

Proteome-wide Mendelian randomization identifies therapeutic targets for ankylosing spondylitis

Background

Ankylosing Spondylitis (AS) is a chronic inflammatory disorder which can lead to considerable pain and disability. Mendelian randomization (MR) has been extensively applied for repurposing licensed drugs and uncovering new therapeutic targets. Our objective is to pinpoint innovative therapeutic protein targets for AS and assess the potential adverse effects of druggable proteins.

Methods

We conducted a comprehensive proteome-wide MR study to assess the causal relationships between plasma proteins and the risk of AS. The plasma proteins were sourced from the UK Biobank Pharma Proteomics Project (UKB-PPP) database, encompassing GWAS data for 2,940 plasma proteins. Additionally, GWAS data for AS were extracted from the R9 version of the Finnish database, including 2,860 patients and 270,964 controls. The colocalization analysis was executed to identify shared causal variants between plasma proteins and AS. Finally, we examined the potential adverse effects of druggable proteins for AS therapy by conducting a phenome-wide association study (PheWAS) utilizing the extensive Finnish database in version R9, encompassing 2,272 phenotypes categorized into 46 groups.

Results

The findings revealed a positive genetic association between the predicted plasma levels of six proteins and an elevated risk of AS, while two proteins exhibited an inverse association with AS risk (P fdr < 0.05). Among these eight plasma proteins, colocalization analysis identified AIF1, TNF, FKBPL, AGER, ALDH5A1, and ACOT13 as shared variation with AS(PPH3+PPH4>0.8), suggesting that they represent potential direct targets for AS intervention. Further phenotype-wide association studies have shown some potential side effects of these six targets (P fdr < 0.05).

Conclusion

Our investigation examined the causal connections between six plasma proteins and AS, providing a comprehensive understanding of potential therapeutic targets.

The molecular response of Mytilus coruscus mantle to shell damage under acute acidified sea water revealed by iTRAQ based quantitative proteomic analysis

Mytilus coruscus is an economically important marine bivalve that lives in estuarine sea areas with seasonal coastal acidification and frequently suffers shell injury in the natural environment. However, the molecular responses and biochemical properties of Mytilus under these conditions are not fully understood. In the present study, we employed tandem mass spectrometry combined with isobaric tagging to identify differentially expressed proteins in the mantle tissue of M. coruscus under different short-term treatments, including shell-complete mussels raised in normal seawater (pH 8.1), shell-damaged mussels raised in normal seawater (pH 8.1), and acidified seawater (pH 7.4). A total of 2694 proteins were identified in the mantle, and analysis of their relative abundance from the three different treatments revealed alterations in the proteins involved in immune regulation, oxidation-reduction processes, protein folding and processing, energy provision, and cytoskeleton. The results obtained by quantitative proteomic analysis of the mantle allowed us to delineate the molecular strategies adopted by M. coruscus in the shell repair process in acidified environments, including an increase in proteins involved in oxidation-reduction processes, protein processing, and cell growth at the expense of proteins involved in immune capacity and energy metabolism. SIGNIFICANCE: The impact of global ocean acidification on calcifying organisms has become a major ecological and environmental problem in the world. Mytilus coruscus is an economically important marine bivalve living in estuary sea area with seasonal coastal acidification, and frequently suffering shell injury in natural environment. Molecular responses of M coruscus under the shell damage and acute acidification is still largely unknown. For this reason, iTRAQ based quantitative proteomic and histological analysis of the mantle from M. coruscus under shell damage and acute acidification were performed, for revealing the proteomic response and possible adaptation mechanism of Mytilus under combined shell damage and acidified sea water, and understanding how the mussel mantle implement a shell-repair process under acidified sea water. Our study provides important data for understanding the shell repair process and proteomic response of Mytilus under ocean acidification, and providing insights into potential adaptation of mussels to future global change.

Protective effect of FKBP12 on dextran sulfate sodium-induced ulcerative colitis in mice as a tacrolimus receptor

Ulcerative colitis (UC) is a multifactorial intestinal disease with a high incidence. In recent years, there has been an urgent need for pleiotropic drugs with a clear biosafety profile. Tacrolimus (TAC) is an immunosuppressant with stronger in vivo effects and better gastrointestinal absorption and is considered a potential treatment for UC. FKBP12 is a mediator of TAC immunosuppression; however, it is unclear whether it can participate in the development of UC in combination with TAC. The purpose of this study is to preliminarily validate the function of FKBP12 by establishing dextran sulfate sodium (DSS)-induced UC model and TAC treatment. The results revealed that TAC was effective in alleviating DSS-induced UC symptoms such as body weight and disease activity index (DAI). TAC significantly protects colonic tissue and attenuates DSS-induced histomorphological changes. In addition, FKBP12 is down-regulated in the intestinal tissue of DSS-induced UC mice and in serum samples of UC patients. In conclusion, our study revealed that FKBP12 may act as a TAC receptor to have anti-inflammatory and protective effects on DSS-induced UC in mice, which will provide a new option for the treatment of UC.

FKBP4 correlates with CD8+ T cells and lymphatic metastases in oral squamous cell carcinoma

OBJECTIVES

To identify the engagement of CD8+ T cells in the lymph node metastasis (LNM) of oral squamous cell carcinoma (OSCC) and significant CD8+ T cell-related genes regulating the LNM.

SUBJECTS AND METHODS

Tumor samples of primary OSCC patients were obtained (n = 71). CD8 expression in LNM- and LNM+ tumors were identified using tissue microarray (TMA)-based immunohistochemistry (IHC) and compared using the Mann-Whitney U test. The LNM status, as well as the metagene expression of CD8+ T cells of OSCC patients, were obtained from The Cancer Genome Atlas (TCGA) database. Metagenes related to LNM were screened using logistic regression analyses and further identified using TMA-based IHC.

RESULTS

CD8 was significantly positively associated with LNM (p < 0.05). Furthermore, tumors with higher expression of FKBP4 had significantly higher LNM rate (HR: 1.63; 95% CI: 1.08 ~ 2.53; p < 0.05), which was also proven using TMA-based IHC analysis.

CONCLUSION

CD8+ T cells might engage in the lymphatic metastases of OSCC. Among CD8+ T cell-related genes, FKBP4 could be a promising biomarker to predict the risk of LNM of OSCC.

Simultaneous determination of HD56, a novel prodrug, and its active metabolite in cynomolgus monkey plasma using LC-MS/MS for elucidating its pharmacokinetic profile

An LC-MS/MS method was developed and validated for the simultaneous determination of the carboxylic acid ester precursor HD56 and the active product HD561 in cynomolgus monkey plasma. Then, the pharmacokinetic characteristics of both compounds following single and multiple i.g. administrations in cynomolgus monkeys were elucidated. In the method, chromatographic separation was achieved with a C18 reversed-phase column and the target quantification was carried out by an electrospray ionization (ESI) source coupled with triple quadrupole mess detector in positive ionization mode with multiple reaction monitoring (MRM) approach. Using the quantification method, the in vitro stability of HD56 in plasma and HD56 pharmacokinetic behavior after i.g. administration in cynomolgus monkey were investigated. It was approved that HD56 did convert into HD561 post-administration. The overall systemic exposure of HD561 post-conversion from HD56 accounted for only about 17% of HD56. After repeated administration at the same dose, there was no significant difference in exposure levels of both HD56 and HD561. However, after multiple dosing, the exposure of HD56 tended to decrease while that of HD561 tended to increase, resulting in a 30% in the exposure ratio. Remarkably, with a carboxylesterase (CES) activity profile akin to humans, the observed in vivo pharmacokinetic profile in cynomolgus monkeys holds promise for predicting HD56/HD561 PK profiles in humans.

Injectable thermosensitive hydrogel loading erythropoietin and FK506 alleviates gingival inflammation and promotes periodontal tissue regeneration

Background: Periodontitis is a chronic multifactorial inflammatory disease associated with dysbiotic plaque biofilms and characterized by progressive destruction of the tooth-supporting apparatus. Therefore, there is significant potential in the discovery of drugs that inhibit periodontal inflammatory responses and promote periodontal regeneration. Methods: In this study, we generated a periodontitis rat model to detect the effects of chitosan/β-sodium glycerophosphate (β-GP)/glycolic acid (GA) hydrogel carried Erythropoietin and FK506 (EPO-FK506-CS/β-GP/GA). A total of forty-eight male Wistar rats were used to establish the periodontitis model. Drug injection was administered every 3 days for a total of five times over a 2-week period. After a period of 2 weeks following implantation, the rats underwent anesthesia, and a section of their maxillae encompassing the maxillary first and second molars, along with the alveolar bone, was obtained. micro-CT scanning, histopathology, immunohistochemistry and reverse transcription-quantitative PCR (RT-qPCR) assays were performed. Meanwhile, ELISA assay was performed to detect the levels of inflammatory mediators (TNF-α, IL-6 and IL-1β). Results: The synthesis and characterization of EPO-FK506-CS/β-GP/GA revealed that the hydrogel has stability and sustained release of drugs. The application of FK506+EPO was found to significantly enhance new bone formation in the defect area, as evidenced by the results of HE staining. Additionally, the use of FK506+EPO in the treated groups led to a notable increase in the density of alveolar bone, as observed through micro-CT analysis, when compared to the Model group. EPO-FK506-CS/β-GP/GA hydrogel exhibited notable efficacy in modulating inflammatory mediators (TNF-α, IL-6 and IL-1β). Furthermore, the osteoinductive properties of the EPO-FK506-CS/β-GP/GA hydrogel were extensive, as evidenced by a significant upregulation in the expression of key markers (Collagen I, Runx2, OPN, and OCN) associated with osteoblastic differentiation. Conclusion: Taken together, EPO-FK506-CS/β-GP/GA hydrogel alleviates gingival inflammation and promotes periodontal tissue regeneration in the periodontitis.

The prognostic and immunological role of FKBP1A in an integrated muti-omics cancers analysis, especially lung cancer

BACKGROUND AND AIM

FKBP1A, a gene encoding the FK506-binding protein 1A, has emerged as a significant player in cancer progression and prognosis. This study aimed to comprehensively investigate the multifaceted role of FKBP1A in cancer, focusing on its differential expression patterns, prognostic implications, genetic alterations, and associations with the tumor microenvironment.

METHODS AND RESULTS

Using large-scale datasets, including GTEx, TCGA, HPA, and cBioPortal, we analyzed FKBP1A expression across normal tissues and various cancer types. Our findings revealed that FKBP1A exhibited aberrant upregulation in most human cancers, making it a potential biomarker for malignancy. Moreover, FKBP1A expression correlated with poor overall survival, disease-specific survival, disease-free interval, and progression-free interval in several cancers, indicating its prognostic significance. Genetic alteration analysis showed that FKBP1A gene amplification was prevalent, particularly in ovarian cancer. Furthermore, FKBP1A expression was associated with tumor mutational burden and microsatellite instability, highlighting its potential involvement in tumor-immune response. Notably, FKBP1A expression positively correlated with stromal and immune cell scores, suggesting its role in shaping the tumor microenvironment. Additionally, according to the functional enrichment analysis, experimental validation in lung adenocarcinoma confirmed the role of FKBP1A through the regulation of EGFR signaling by apoptosis, which is consistent with drug sensitivity analysis to some extent.

CONCLUSION

In conclusion, FKBP1A exhibits differential expression in cancer, serves as a prognostic indicator, undergoes genetic alterations, and influences the tumor-immune microenvironment. These findings shed light on the multifaceted role of FKBP1A in cancer development and progression, suggesting its potential as a therapeutic target and guidance of clinical drugs selection, and provide valuable insights into patient prognosis for interventions based on pharmaceuticals.

The transportosome system as a model for the retrotransport of soluble proteins

The classic model of action of the glucocorticoid receptor (GR) sustains that its associated heat-shock protein of 90-kDa (HSP90) favours the cytoplasmic retention of the unliganded GR, whereas the binding of steroid triggers the dissociation of HSP90 allowing the passive nuclear accumulation of GR. In recent years, it was described a molecular machinery called transportosome that is responsible for the active retrograde transport of GR. The transportosome heterocomplex includes a dimer of HSP90, the stabilizer co-chaperone p23, and FKBP52 (FK506-binding protein of 52-kDa), an immunophilin that binds dynein/dynactin motor proteins. The model shows that upon steroid binding, FKBP52 is recruited to the GR allowing its active retrograde transport on cytoskeletal tracks. Then, the entire GR heterocomplex translocates through the nuclear pore complex. The HSP90-based heterocomplex is released in the nucleoplasm followed by receptor dimerization. Subsequent findings demonstrated that the transportosome is also responsible for the retrotransport of other soluble proteins. Importantly, the disruption of this molecular oligomer leads to several diseases. In this article, we discuss the relevance of this transport machinery in health and disease.

Multi-Omics Analysis Reveals the Pathogenesis of Growth-Disordered Raccoon Dog

Microorganisms of the genus Eperythrozoon are a zoonotic chronic infectious disease with wide distribution. We found that raccoons infected with Eperythrozoon showed obvious stunting, which seriously affected the economic benefits of raccoon dogs. To investigate the pathogenesis of the raccoon dog, we used transcriptome and proteome sequencing to analyze the changes in mRNA, miRNA, and protein expression in raccoon dogs infected with Eperythrozoon and normal raccoons. The results showed that the expression levels of genes related to immunity, metabolism, and enzyme activity were significantly changed. Among these, ERLIN1, IGF1R, CREB3L1, TNS1, TENC1, and mTOR play key roles. Additionally, the miR-1268, miR-125b, miR-10-5p, and miR-10 as central miRNAs regulate the expression of these genes. Integrated transcriptomic and proteomic analyses revealed consistent trends in mRNA and protein changes in MYH9, FKBP1A, PRKCA, and CYP11B2. These results suggest that Eperythrozoon may contribute to the slow development of raccoons by affecting the expression of mRNAs and miRNAs, reducing their immunity and causing metabolic abnormalities.

Cannabidiol alleviates neuroinflammation and attenuates neuropathic pain via targeting FKBP5

Microglia is a heterogeneous population that mediates neuroinflammation in the central nervous system (CNS) and plays a crucial role in developing neuropathic pain. FKBP5 facilitates the assembly of the IκB kinase (IKK) complex for the activation of NF-κB, which arises as a novel target for treating neuropathic pain. In this study, cannabidiol (CBD), a main active component of Cannabis, was identified as an antagonist of FKBP5. In vitro protein intrinsic fluorescence titration showed that CBD directly bound to FKBP5. Cellular thermal shift assay (CETSA) indicated that CBD binding increased the FKBP5 stability, which implies that FKBP5 is the endogenous target of CBD. CBD was found to inhibit the assembly of the IKK complex and the activation of NF-κB, therefore blocking LPS-induced NF-κB downstream pro-inflammatory factors NO, IL-1β, IL-6 and TNF-α. Stern-Volmer analysis and protein thermal shift assay revealed that tyrosine 113 (Y113) of FKBP5 was critical for FKBP5 interacting with CBD, which is consistent with in silico molecular docking simulation. FKBP5 Y113 mutation (Y113A) alleviated the effect of CBD inhibiting LPS-induced pro-inflammatory factors overproduction. Furthermore, systemic administration of CBD inhibited chronic constriction injury (CCI)-induced microglia activation and FKBP5 overexpression in lumbar spinal cord dorsal horn. These data imply that FKBP5 is an endogenous target of CBD.

PROTACs: A novel strategy for cancer drug discovery and development

Proteolysis targeting chimera (PROTAC) technology has become a powerful strategy in drug discovery, especially for undruggable targets/proteins. A typical PROTAC degrader consists of three components: a small molecule that binds to a target protein, an E3 ligase ligand (consisting of an E3 ligase and its small molecule recruiter), and a chemical linker that hooks first two components together. In the past 20 years, we have witnessed advancement of multiple PROTAC degraders into the clinical trials for anticancer therapies. However, one of the major challenges of PROTAC technology is that only very limited number of E3 ligase recruiters are currently available as E3 ligand for targeted protein degradation (TPD), although human genome encodes more than 600 E3 ligases. Thus, there is an urgent need to identify additional effective E3 ligase recruiters for TPD applications. In this review, we summarized the existing RING-type E3 ubiquitin ligase and their small molecule recruiters that act as effective E3 ligands of PROTAC degraders and their application in anticancer drug discovery. We believe that this review could serve as a reference in future development of efficient E3 ligands of PROTAC technology for cancer drug discovery and development.

A multi-omics investigation of tacrolimus off-target effects on a proximal tubule cell-line

INTRODUCTION

Tacrolimus, an immunosuppressive drug prescribed to a majority of organ transplant recipients is nephrotoxic, through still unclear mechanisms. This study on a lineage of proximal tubular cells using a multi-omics approach aims to detect off-target pathways modulated by tacrolimus that can explain its nephrotoxicity.

METHODS

LLC-PK1 cells were exposed to 5µM of tacrolimus for 24h in order to saturate its therapeutic target FKBP12 and other high-affine FKBPs and favour its binding to less affine targets. Intracellular proteins and metabolites, and extracellular metabolites were extracted and analysed by LC-MS/MS. The transcriptional expression of the dysregulated proteins PCK-1, as well as of the other gluconeogenesis-limiting enzymes FBP1 and FBP2, was measured using RT-qPCR. Cell viability with this concentration of tacrolimus was further checked until 72h.

RESULTS

In our cell model of acute exposure to a high concentration of tacrolimus, different metabolic pathways were impacted including those of arginine (e.g., citrulline, ornithine) (p<0.0001), amino acids (e.g., valine, isoleucine, aspartic acid) (p<0.0001) and pyrimidine (p<0.01). In addition, it induced oxidative stress (p<0.01) as shown by a decrease in total cell glutathione quantity. It impacted cell energy through an increase in Krebs cycle intermediates (e.g., citrate, aconitate, fumarate) (p<0.01) and down-regulation of PCK-1 (p<0.05) and FPB1 (p<0.01), which are key enzymes in gluconeogenesis and acid-base balance control.

DISCUSSION

The variations found using a multi-omics pharmacological approach clearly point towards a dysregulation of energy production and decreased gluconeogenesis, a hallmark of chronic kidney disease which may also be an important toxicity pathways of tacrolimus.

The Scaffold Immunophilin FKBP51 Is a Phosphoprotein That Undergoes Dynamic Mitochondrial-Nuclear Shuttling

The immunophilin FKBP51 forms heterocomplexes with molecular chaperones, protein-kinases, protein-phosphatases, autophagy-related factors, and transcription factors. Like most scaffold proteins, FKBP51 can use a simple tethering mechanism to favor the efficiency of interactions with partner molecules, but it can also exert more complex allosteric controls over client factors, the immunophilin itself being a putative regulation target. One of the simplest strategies for regulating pathways and subcellular localization of proteins is phosphorylation. In this study, it is shown that scaffold immunophilin FKBP51 is resolved by resolutive electrophoresis in various phosphorylated isoforms. This was evidenced by their reactivity with specific anti-phosphoamino acid antibodies and their fade-out by treatment with alkaline phosphatase. Interestingly, stress situations such as exposure to oxidants or in vivo fasting favors FKBP51 translocation from mitochondria to the nucleus. While fasting involves phosphothreonine residues, oxidative stress involves tyrosine residues. Molecular modeling predicts the existence of potential targets located at the FK1 domain of the immunophilin. Thus, oxidative stress favors FKBP51 dephosphorylation and protein degradation by the proteasome, whereas FK506 binding protects the persistence of the post-translational modification in tyrosine, leading to FKBP51 stability under oxidative conditions. Therefore, FKBP51 is revealed as a phosphoprotein that undergoes differential phosphorylations according to the stimulus.

Dysregulated long non-coding RNA in Sjögren's disease impacts both interferon and adaptive immune responses

OBJECTIVE

Sjögren's disease (SjD) is an autoimmune disease characterised by inflammatory destruction of exocrine glands. Patients with autoantibodies to Ro/SSA (SjDRo+) exhibit more severe disease. Long non-coding RNAs (lncRNAs) are a functionally diverse class of non-protein-coding RNAs whose role in autoimmune disease pathology has not been well characterised.

METHODS

Whole blood RNA-sequencing (RNA-seq) was performed on SjD cases (n=23 Ro/SSA negative (SjDRo-); n=27 Ro/SSA positive (SjDRo+) and healthy controls (HCs; n=27). Bioinformatics and pathway analyses of differentially expressed (DE) transcripts (log2 fold change ≥2 or ≤0.5; padj<0.05) were used to predict lncRNA function. LINC01871 was characterised by RNA-seq analyses of HSB-2 cells with CRISPR-targeted LINC01871 deletion (LINC01871-/ -) and in vitro stimulation assays.

RESULTS

Whole blood RNA-seq revealed autoantibody-specific transcription profiles and disproportionate downregulation of DE transcripts in SjD cases relative to HCs. Sixteen DE lncRNAs exhibited correlated expression with the interferon (IFN)-regulated gene, RSAD2, in SjDRo+ (r≥0.65 or ≤-0.6); four antisense lncRNAs exhibited IFN-regulated expression in immune cell lines. LINC01871 was upregulated in all SjD cases. RNA-seq and pathway analyses of LINC01871-/ - cells implicated roles in cytotoxic function, differentiation and IFNγ induction. LINC01871 was induced by IFNγ in a myeloid cell line and regulated by calcineurin/NFAT pathway and T cell receptor (TCR) signalling in primary human T cells.

CONCLUSION

LINC01871 influences expression of many immune cell genes and growth factors, is IFNγ inducible, and regulated by calcineurin signalling and TCR ligand engagement. Altered LINC01871 expression may influence the dysregulated T cell inflammatory pathways implicated in SjD.

The emerging importance of immunophilins in fibrosis development

Immunophilins are a family of proteins encompassing FK506-binding proteins (FKBPs) and cyclophilins (Cyps). FKBPs and Cyps exert peptidyl-prolyl cis-trans isomerase (PPIase) activity, which facilitates diverse protein folding assembly, or disassembly. In addition, they bind to immunosuppressant medications where FKBPs bind to tacrolimus (FK506) and rapamycin, whereas cyclophilins bind to cyclosporin. Some large immunophilins have domains other than PPIase referred to as tetratricopeptide (TPR) domain, which is involved in heat shock protein 90 (Hsp90) and heat shock protein 70 (Hsp 70) chaperone interaction. The TPR domain confers immunophilins’ pleotropic actions to mediate various physiological and biochemical processes. So far, immunophilins have been implicated to play an important role in pathophysiology of inflammation, cancer and neurodegenerative disorders. However, their importance in the development of fibrosis has not yet been elucidated. In this review we focus on the pivotal functional and mechanistic roles of different immunophilins in fibrosis establishment affecting various organs. The vast majority of the studies reported that cyclophilin A, FKBP12 and FKBP10 likely induce organ fibrosis through the calcineurin or TGF-β pathways. FKBP51 demonstrated a role in myelofibrosis development through calcineurin-dependant pathway, STAT5 or NF-κB pathways. Inhibition of these specific immunophilins has been shown to decrease the extent of fibrosis suggesting that immunophilins could be a novel promising therapeutic target to prevent or reverse fibrosis.

The Prognostic Significance of FKBP1A and Its Related Immune Infiltration in Liver Hepatocellular Carcinoma

Liver hepatocellular carcinoma (LIHC) remains a global health challenge with poor prognosis and high mortality. FKBP1A was first discovered as a receptor for the immunosuppressant drug FK506 in immune cells and is critical for various tumors and cancers. However, the relationships between FKBP1A expression, cellular distribution, tumor immunity, and prognosis in LIHC remain unclear. Here, we investigated the expression level of FKBP1A and its prognostic value in LIHC via multiple datasets including ONCOMINE, TIMER, GEPIA, UALCAN, HCCDB, Kaplan–Meier plotter, LinkedOmics, and STRING. Human liver tissue microarray was employed to analyze the characteristics of FKBP1A protein including the expression level and pathological alteration in cellular distribution. FKBP1A expression was significantly higher in LIHC and correlated with tumor stage, grade and metastasis. The expression level of the FKBP1A protein was also increased in LIHC patients along with its accumulation in endoplasmic reticulum (ER). High FKBP1A expression was correlated with a poor survival rate in LIHC patients. The analysis of gene co-expression and the regulatory pathway network suggested that FKBP1A is mainly involved in protein synthesis, metabolism and the immune-related pathway. FKBP1A expression had a significantly positive association with the infiltration of hematopoietic immune cells including B cells, CD8⁺ T cells, CD4⁺ T cells, macrophages, neutrophils, and dendritic cells. Moreover, M2 macrophage infiltration was especially associated with a poor survival prognosis in LIHC. Furthermore, FKBP1A expression was significantly positively correlated with the expression of markers of M2 macrophages and immune checkpoint proteins such as PD-L1, CTLA-4, LAG3 and HAVCR2. Our study demonstrated that FKBP1A could be a potential prognostic target involved in tumor immune cell infiltration in LIHC.

Expression pattern and clinical value of Key RNA methylation modification regulators in ischemic stroke

Ischemic stroke (IS) is one of the major causes of death and disability worldwide, and effective diagnosis and treatment methods are lacking. RNA methylation, a common epigenetic modification, plays an important role in disease progression. However, little is known about the role of RNA methylation modification in the regulation of IS. The aim of this study was to investigate RNA methylation modification patterns and immune infiltration characteristics in IS through bioinformatics analysis. We downloaded gene expression profiles of control and IS model rat brain tissues from the Gene Expression Omnibus database. IS profiles were divided into two subtypes based on RNA methylation regulators, and functional enrichment analyses were conducted to determine the differentially expressed genes (DEGs) between the subtypes. Weighted gene co-expression network analysis was used to explore co-expression modules and genes based on DEGs. The IS clinical diagnosis model was successfully constructed and four IS characteristic genes (GFAP, GPNMB, FKBP9, and CHMP5) were identified, which were significantly upregulated in IS samples. Characteristic genes were verified by receiver operating characteristic curve and real-time quantitative PCR analyses. The correlation between characteristic genes and infiltrating immune cells was determined by correlation analysis. Furthermore, GPNMB was screened using the protein-protein interaction network, and its regulatory network and the potential therapeutic drug chloroquine were predicted. Our finding describes the expression pattern and clinical value of key RNA methylation modification regulators in IS and novel diagnostic and therapeutic targets of IS from a new perspective.

Progesterone as an Anti-Inflammatory Drug and Immunomodulator: New Aspects in Hormonal Regulation of the Inflammation

The specific regulation of inflammatory processes by steroid hormones has been actively studied in recent years, especially by progesterone (P₄) and progestins. The mechanisms of the anti-inflammatory and immunomodulatory P₄ action are not fully clear. The anti-inflammatory effects of P₄ can be defined as nonspecific, associated with the inhibition of NF-κB and COX, as well as the inhibition of prostaglandin synthesis, or as specific, associated with the regulation of T-cell activation, the regulation of the production of pro- and anti-inflammatory cytokines, and the phenomenon of immune tolerance. The specific anti-inflammatory effects of P₄ and its derivatives (progestins) can also include the inhibition of proliferative signaling pathways and the antagonistic action against estrogen receptor beta-mediated signaling as a proinflammatory and mitogenic factor. The anti-inflammatory action of P₄ is accomplished through the participation of progesterone receptor (PR) chaperones HSP90, as well as immunophilins FKBP51 and FKBP52, which are the validated targets of clinically approved immunosuppressive drugs. The immunomodulatory and anti-inflammatory effects of HSP90 inhibitors, tacrolimus and cyclosporine, are manifested, among other factors, due to their participation in the formation of an active ligand–receptor complex of P₄ and their interaction with its constituent immunophilins. Pharmacological agents such as HSP90 inhibitors can restore the lost anti-inflammatory effect of glucocorticoids and P₄ in chronic inflammatory and autoimmune diseases. By regulating the activity of FKBP51 and FKBP52, it is possible to increase or decrease hormonal signaling, as well as restore it during the development of hormone resistance. The combined action of immunophilin suppressors with steroid hormones may be a promising strategy in the treatment of chronic inflammatory and autoimmune diseases, including endometriosis, stress-related disorders, rheumatoid arthritis, and miscarriages. Presumably, the hormone receptor- and immunophilin-targeted drugs may act synergistically, allowing for a lower dose of each.

Rapamycin Alleviates 2,4,6-Trinitrobenzene Sulfonic Acid-Induced Colitis through Autophagy Induction and NF-κB Pathway Inhibition in Mice

Background

Recent genetic studies indicated that variants of autophagy genes were associated with the predisposition of Crohn's disease (CD). The autophagy deficiency may affect the innate and adaptive immunity, which is related to persistent and excessive inflammation of the bowel. However, it remains unclear how autophagy modulates the expression of immune response regulator NF-κB and proinflammatory cytokine TNF-α in CD.

Aim

We aimed to investigate the role of rapamycin on the expression of NF-κB p65 and TNF-α in 2, 4, 6-trinitrobenzene sulfonic acid (TNBS)-induced mouse colitis and lipopolysaccharide (LPS)-induced HT-29 cells.

Methods

TNBS-induced colitis mice were treated with saline or rapamycin, and the disease activity index (DAI) and histological scores of colonic mucosa were evaluated. The expressions of p65, ATG16L1 and LC3 were detected by western blot and immunohistochemistry staining. The monodansylcadaverine (MDC) staining and transmission electron microscopy were developed to study the autophagy in LPS-induced HT-29 cells. Expression of TNF-α from colon tissue and HT-29 cells were detected by ELISA. The expressions of p65, ATG16L1 and LC3 in active CD patients were also investigated.

Results

Significantly more autophagosomes were observed in rapamycin-treated cells than in controls. Rapamycin remarkably upregulated the expression of ATG16L1 and LC3II, inhibited p65 nucleus translocation and secretion of TNF-α both in vivo and in vitro. The expression of both ATG16L1 and LC3II increased in mild to moderate CD specimens, while no significant difference was noted between severe CD and normal controls. The expression of p65 increased notably in severe CD compared to those in mild to moderate patients.

Conclusions

In LPS-treated HT-29 cells and TNBS-induced colitis, p65 is overexpressed, which results in exaggerated secretion of TNF-α and induce or worsen the inflammation in the bowel. Rapamycin protects against colitis through induction of autophagy, thus inhibiting the activation of NF-κB pathway and secretion of TNF-α.

mTOR: A Potential New Target in Nonalcoholic Fatty Liver Disease

The global prevalence of nonalcoholic fatty liver disease (NAFLD) continues to rise, yet effective treatments are lacking due to the complex pathogenesis of this disease. Although recent research has provided evidence for the “multiple strikes” theory, the classic “two strikes” theory has not been overturned. Therefore, there is a crucial need to identify multiple targets in NAFLD pathogenesis for the development of diagnostic markers and targeted therapeutics. Since its discovery, the mechanistic target of rapamycin (mTOR) has been recognized as the central node of a network that regulates cell growth and development and is closely related to liver lipid metabolism and other processes. This paper will explore the mechanisms by which mTOR regulates lipid metabolism (SREBPs), insulin resistance (Foxo1, Lipin1), oxidative stress (PIG3, p53, JNK), intestinal microbiota (TLRs), autophagy, inflammation, genetic polymorphisms, and epigenetics in NAFLD. The specific influence of mTOR on NAFLD was hypothesized to be divided into micro regulation (the mechanism of mTOR’s influence on NAFLD factors) and macro mediation (the relationship between various influencing factors) to summarize the influence of mTOR on the developmental process of NAFLD, and prove the importance of mTOR as an influencing factor of NAFLD regarding multiple aspects. The effects of crosstalk between mTOR and its upstream regulators, Notch, Hedgehog, and Hippo, on the occurrence and development of NAFLD-associated hepatocellular carcinoma are also summarized. This analysis will hopefully support the development of diagnostic markers and new therapeutic targets in NAFLD.

FKBP51, AmotL2 and IQGAP1 Involvement in Cilastatin Prevention of Cisplatin-Induced Tubular Nephrotoxicity in Rats

The immunophilin FKBP51, the angiomotin AmotL2, and the scaffoldin IQGAP1 are overexpressed in many types of cancer, with the highest increase in leucocytes from patients undergoing oxaliplatin chemotherapy. Inflammation is involved in the pathogenesis of nephrotoxicity induced by platinum analogs. Cilastatin prevents renal damage caused by cisplatin. This functional and confocal microscopy study shows the renal focal-segmental expression of TNFα after cisplatin administration in rats, predominantly of tubular localization and mostly prevented by co-administration of cilastatin. FKBP51, AmotL2 and IQGAP1 protein expression increases slightly with cilastatin administration and to a much higher extent with cisplatin, in a cellular- and subcellular-specific manner. Kidney tubule cells expressing FKBP51 show either very low or no expression of TNFα, while cells expressing TNFα have low levels of FKBP51. AmotL2 and TNFα seem to colocalize and their expression is increased in tubular cells. IQGAP1 fluorescence increases with cilastatin, cisplatin and joint cilastatin-cisplatin treatment, and does not correlate with TNFα expression or localization. These data suggest a role for FKBP51, AmotL2 and IQGAP1 in cisplatin toxicity in kidney tubules and in the protective effect of cilastatin through inhibition of dehydropeptidase-I.

Dexamethasone promotes breast cancer stem cells in obese and not lean mice

Obesity is highly prevalent in breast cancer patients and is associated with increased recurrence and breast cancer-specific mortality. Glucocorticoids (GC) are used as an adjuvant in cancer treatment and are associated with promoting breast cancer metastasis through activation of stemness-related pathways. Therefore, we utilized the synergetic allograft E0771 breast cancer model to investigate if treatment with GCs had differential effects on promoting cancer stem cells in lean and diet-induced obese mice. Indeed, both lean mice treated with dexamethasone and obese mice with no treatment had no effect on the ex vivo colony-forming ability, mammosphere formation, or aldehyde dehydrogenase (ALDH) bright subpopulation. However, treatment of obese mice with dexamethasone resulted in a significant increase in ex vivo colony formation, mammosphere formation, ALDH bright subpopulation, and expression of pluripotency transcription factors. GC transcriptionally regulated genes were not altered in the dexamethasone-treated groups compared to treatment controls. In summary, these results provide initial evidence that obesity presents a higher risk of GC-induced cancer stemness via non-genomic GC signaling which is of potential translational significance.

FKBP52 in Neuronal Signaling and Neurodegenerative Diseases: A Microtubule Story

The FK506-binding protein 52 (FKBP52) belongs to a large family of ubiquitously expressed and highly conserved proteins (FKBPs) that share an FKBP domain and possess Peptidyl-Prolyl Isomerase (PPIase) activity. PPIase activity catalyzes the isomerization of Peptidyl-Prolyl bonds and therefore influences target protein folding and function. FKBP52 is particularly abundant in the nervous system and is partially associated with the microtubule network in different cell types suggesting its implication in microtubule function. Various studies have focused on FKBP52, highlighting its importance in several neuronal microtubule-dependent signaling pathways and its possible implication in neurodegenerative diseases such as tauopathies (i.e., Alzheimer disease) and alpha-synucleinopathies (i.e., Parkinson disease). This review summarizes our current understanding of FKBP52 actions in the microtubule environment, its implication in neuronal signaling and function, its interactions with other members of the FKBPs family and its involvement in neurodegenerative disease.

Biomarkers of everolimus efficacy in breast cancer therapy

OBJECTIVE

Everolimus is an inhibitor of serine/ threonine kinase mTOR. The drug is approved for the treatment of metastatic ER positive, HER2 negative breast cancers and benefits a subset of patients with these breast cancers in combination with hormonal therapies. Despite extensive efforts, no additional predictive biomarkers to guide therapeutic decisions for everolimus have been introduced in clinical practice.

DATA SOURCES

This paper discusses predictive biomarkers for everolimus efficacy in breast cancer. A search of the medline and web of science databases was performed using the words "everolimus" and "biomarkers". References of retrieved articles were manually scanned for additional relevant articles.

DATA SUMMARY

Everolimus benefits a subset of patients with metastatic ER positive, HER2 negative breast cancers in combination with hormonal therapies. Despite extensive efforts no additional predictive biomarkers to guide therapeutic decisions for everolimus therapy have been confirmed for use in clinical practice. However, promising biomarker leads for everolimus efficacy in breast cancer have been suggested and include expression of proteins in the mTOR pathway in ER positive, HER2 negative breast cancers. In HER2 positive cancers PIK3CA mutations, and PTEN expression loss are prognostic. Other clinical predictive biomarkers with more limited data include characteristics derived from whole genome sequencing, subsets of circulating leukocytes and changes in Standardized Uptake Values (SUV) of Positron Emission Tomography (PET) scans.

CONCLUSIONS

Putative predictive biomarkers for everolimus efficacy in breast cancer patients, both genomic and clinical, deserve further study and could lead to a better selection of responsive patients.

Mutations in Hsp90 Cochaperones Result in a Wide Variety of Human Disorders

The Hsp90 molecular chaperone, along with a set of approximately 50 cochaperones, mediates the folding and activation of hundreds of cellular proteins in an ATP-dependent cycle. Cochaperones differ in how they interact with Hsp90 and their ability to modulate ATPase activity of Hsp90. Cochaperones often compete for the same binding site on Hsp90, and changes in levels of cochaperone expression that occur during neurodegeneration, cancer, or aging may result in altered Hsp90-cochaperone complexes and client activity. This review summarizes information about loss-of-function mutations of individual cochaperones and discusses the overall association of cochaperone alterations with a broad range of diseases. Cochaperone mutations result in ciliary or muscle defects, neurological development or degeneration disorders, and other disorders. In many cases, diseases were linked to defects in established cochaperone-client interactions. A better understanding of the functional consequences of defective cochaperones will provide new insights into their functions and may lead to specialized approaches to modulate Hsp90 functions and treat some of these human disorders.

The Construction of a Prognostic Model Based on a Peptidyl Prolyl Cis-Trans Isomerase Gene Signature in Hepatocellular Carcinoma

Objective: The aim of the present study was to construct a prognostic model based on the peptidyl prolyl cis–trans isomerase gene signature and explore the prognostic value of this model in patients with hepatocellular carcinoma.

Methods: The transcriptome and clinical data of hepatocellular carcinoma patients were downloaded from The Cancer Genome Atlas and the International Cancer Genome Consortium database as the training set and validation set, respectively. Peptidyl prolyl cis–trans isomerase gene sets were obtained from the Molecular Signatures Database. The differential expression of peptidyl prolyl cis–trans isomerase genes was analyzed by R software. A prognostic model based on the peptidyl prolyl cis–trans isomerase signature was established by Cox, Lasso, and stepwise regression methods. Kaplan–Meier survival analysis was used to evaluate the prognostic value of the model and validate it with an independent external data. Finally, nomogram and calibration curves were developed in combination with clinical staging and risk score.

Results: Differential gene expression analysis of hepatocellular carcinoma and adjacent tissues showed that there were 16 upregulated genes. A prognostic model of hepatocellular carcinoma was constructed based on three gene signatures by Cox, Lasso, and stepwise regression analysis. The Kaplan–Meier curve showed that hepatocellular carcinoma patients in high-risk score group had a worse prognosis (p < 0.05). The receiver operating characteristic curve revealed that the area under curve values of predicting the survival rate at 1, 2, 3, 4, and 5 years were 0.725, 0.680, 0.644, 0.630, and 0.639, respectively. In addition, the evaluation results of the model by the validation set were basically consistent with those of the training set. A nomogram incorporating clinical stage and risk score was established, and the calibration curve matched well with the diagonal.

Conclusion: A prognostic model based on 3 peptidyl prolyl cis–trans isomerase gene signatures is expected to provide reference for prognostic risk stratification in patients with hepatocellular carcinoma.

Combination Therapy With Rapamycin and Low Dose Imatinib in Pulmonary Hypertension

Rationale: Enhanced proliferation and distal migration of human pulmonary arterial smooth muscle cells (hPASMCs) both contribute to the progressive increases in pulmonary vascular remodeling and resistance in pulmonary arterial hypertension (PAH). Our previous studies revealed that Rictor deletion, to disrupt mTOR Complex 2 (mTORC2), over longer periods result in a paradoxical rise in platelet-derived growth factor receptor (PDGFR) expression in PASMCs. Thus, the purpose of this study was to evaluate the role of combination therapy targeting both mTOR signaling with PDGFR inhibition to attenuate the development and progression of PAH.

Methods and Results: Immunoblotting analyses revealed that short-term exposure to rapamycin (6h) significantly reduced phosphorylation of p70S6K (mTORC1-specific) in hPASMCs but had no effect on the phosphorylation of AKT (p-AKT S473, considered mTORC2-specific). In contrast, longer rapamycin exposure (>24 h), resulted in differential AKT (T308) and AKT (S473) phosphorylation with increases in phosphorylation of AKT at T308 and decreased phosphorylation at S473. Phosphorylation of both PDGFRα and PDGFRβ was increased in hPASMCs after treatment with rapamycin for 48 and 72 h. Based on co-immunoprecipitation studies, longer exposure to rapamycin (24–72 h) significantly inhibited the binding of mTOR to Rictor, mechanistically suggesting mTORC2 inhibition by rapamycin. Combined exposure of rapamycin with the PDGFR inhibitor, imatinib significantly reduced the proliferation and migration of hPASMCs compared to either agent alone. Pre-clinical studies validated increased therapeutic efficacy of rapamycin combined with imatinib in attenuating PAH over either drug alone. Specifically, combination therapy further attenuated the development of monocrotaline (MCT)- or Hypoxia/Sugen-induced pulmonary hypertension (PH) in rats as demonstrated by further reductions in the Fulton index, right ventricular systolic pressure (RVSP), pulmonary vascular wall thickness and vessel muscularization, and decreased proliferating cell nuclear antigen (PCNA) staining in PASMCs.

Conclusion: Prolonged rapamycin treatment activates PDGFR signaling, in part, via mTORC2 inhibition. Combination therapy with rapamycin and imatinib may be a more effective strategy for the treatment of PAH.

Corticosteroid receptors as a model for the Hsp90•immunophilin-based transport machinery

Steroid receptors form soluble heterocomplexes with the 90-kDa heat-shock protein (Hsp90) and other chaperones and co-chaperones. The assembly and composition of the oligomer is influenced by the presence and nature of the bound steroid. Although these receptors shuttle dynamically in and out of the nucleus, their primary localization in the absence of steroid can be mainly cytoplasmic, mainly nuclear, or partitioned into both cellular compartments. Upon steroid binding, receptors become localized to the nucleus via the transportosome, a retrotransport molecular machinery that comprises Hsp90, a high-molecular-weight immunophilin, and dynein motors. This molecular machinery, first evidenced in steroid receptors, can also be used by other soluble proteins. In this review, we dissect the complete model of this transport machinery system.