Clinical science最新文献

Heart failure with preserved ejection fraction (HFpEF) represents the initial phase of cardiac dysfunction associated with type 2 diabetes mellitus (T2DM). To date, the pathophysiological mechanisms underlying T2DM-induced HFpEF are complex and elusive. Fibroblast activation protein (FAP) is a prolyl-specific serine protease whose inhibition or vaccination has been shown to enhance cardiac repair following myocardial infarction (MI). However, the role and underlying molecular mechanisms by which abnormal FAP activity promotes the development of T2DM-induced HFpEF remain to be elucidated. In this study, the plasma activity and level of FAP were significantly higher in the T2DM with HFpEF group compared with the healthy control group. Moreover, plasma FAP activity and level were positively correlated with the likelihood of T2DM with HFpEF. To investigate the mechanistic involvement of FAP in the development of T2DM-associated HFpEF, a chronic T2DM mouse model was established. The results revealed that FAP knockout (KO) significantly improved B-type natriuretic peptide (BNP) level and E/A ratios compared with the wildtype (WT) T2DM group. Additionally, FAP KO and FAP inhibitor Talabostat alleviated myocardial inflammation, fibrosis, cardiomyocyte apoptosis, oxidative stress, and energy metabolism dysfunction. Mechanistically, an abnormal increase in FAP triggered the calmodulin-dependent protein kinase δ (CaMKIIδ)-Calcineurin A-NFATc2 signaling pathway, leading to the aforementioned pathological changes in T2DM-induced HFpEF. In contrast, FAP KO suppressed the CaMKIIδ-Calcineurin A-NFATc2 signaling pathway and attenuated these pathological changes. Overall, these findings suggest that FAP may serve as a critical therapeutic target for T2DM-induced HFpEF.

Adipose tissue dysfunction leads to abnormal lipid metabolism and high inflammation levels. This research aims to explore the role of Serpina3c, which is highly expressed in adipocytes, in obesity-related hypertriglyceridemia and metaflammation. Serpina3c global knockout (KO) mice, adipocyte-specific Serpina3c overexpressing mice, Serpina3c knockdown (KD) mice, and hypoxia-inducible factor 1 alpha (Hif1α) KD mice were fed a high-fat diet (HFD) for 16 weeks to generate obesity-related hypertriglyceridemia mice models. In the present study, Serpina3c KO mice and adipocyte-specific Serpina3c KD mice exhibited more severe obesity-related hypertriglyceridemia and metaflammation under HFD conditions. Serpina3c KO epididymal white adipose tissue (eWAT) primary stromal vascular fraction (SVF)-derived adipocytes exhibited higher lipid (triglyceride and non-esterified fatty acid) levels and higher fatty acid synthase expression after palmitic acid (PA) stimulation. Adipocyte-specific Serpina3c overexpression in KO mice prevented the KO group phenotype. The RNA-seq and in vitro validation revealed that Hif1α and the glycolysis pathways were up-regulated in Serpina3c KD adipocytes, which were all validated by in vitro and in vivo reverse experiments. Co-immunoprecipitation (co-IP) provided evidence that Serpina3c bound nuclear factor erythroid 2-related factor 2 (Nrf2) regulates Hif1α. Nrf2 KD reduced Hif1α and Fasn expression, decreased lipid content, and reduced the extracellular acidification rate in Serpina3c KO adipocytes. Metabolomics revealed that lactic acid (LD) levels in eWAT were responsible for adipose-associated macrophage inflammation. In summary, Serpina3c inhibits the Hif1α-glycolysis pathway and reduces de novo lipogenesis (DNL) and LD secretion in adipocytes by binding to Nrf2, thereby improving HFD-induced lipid metabolism disorders and alleviating adipose tissue macrophage inflammation.

Cardiovascular diseases (CVDs) remain the leading cause of death worldwide, including in the United States. Risk factors such as high cholesterol, diabetes, obesity, smoking, physical inactivity, and hypertension contribute significantly to their development. Emerging evidence highlights a central role for chemokines-small signaling molecules that guide immune cell migration to sites of infection, inflammation, or tissue damage-in the initiation and progression of hypertension. This positions chemokines and their receptors as promising pharmacological targets for blood pressure regulation and vascular protection. In this review, we explore the therapeutic potential of targeting chemokines and their receptors and summarize the main strategies reported in the literature for managing hypertension through these pathways. For this purpose, an analysis of drugs that act on the most relevant receptors at the preclinical and clinical levels was performed. After this analysis, their mechanisms of action, selectivity, and possible adverse effects were discussed. In conclusion, we reinforce that the modulation of chemokines and their receptors represents a promising approach in the control of CVDs, especially hypertension, although further clinical studies are needed to validate the efficacy and safety of this strategy, considering possible impacts on other essential immune responses.

Delayed diabetic wound healing is a global health issue with unclear pathogenesis. Ferroptosis, a form of cell death involving iron and lipid peroxidation, may contribute to delayed diabetic wound. This study investigates the role of ferroptosis in diabetic wound keratinocytes. We measured lipid peroxidation products (MDA, 4-HNE), ACSL4, and GPX4 protein levels in diabetic keratinocytes and assessed mitochondrial morphology. Ferrostatin-1 (Fer-1) was used to inhibit ferroptosis in diabetic rat wounds, and its effects on healing and expression levels were evaluated. Pull-down assays, silver staining, and mass spectrometry were employed to study ACSL4 mRNA regulation. A YTHDF2 knockdown adenovirus was used to manipulate YTHDF2 expression in rat wounds. Ferroptosis was detected in diabetic keratinocytes, hindering wound healing, a process reversible with Fer-1. High glucose induced ACSL4 expression, driving keratinocyte ferroptosis and delayed healing. YTHDF2 interacts with N6-methyladenosine-modified ACSL4 mRNA, affecting its stability and expression. YTHDF2 knockdown increased ACSL4, promoting ferroptosis and impairing healing. Our findings illustrate the significant involvement of ferroptosis in the dysfunction of diabetic keratinocytes, suggesting that targeting ferroptosis may offer a viable therapeutic approach for improving diabetic wound healing.

Limited drug therapies for peripheral artery disease (PAD)-related walking impairment exist. There has been a recent interest in repurposing the diabetes medication metformin to treat PAD. Animal studies designed to develop new PAD drug therapies have mainly used a model of temporary hind limb ischaemia (HLI). The aim of this study was to test whether metformin improved blood supply and ambulation in a novel mouse model with ongoing HLI. Stable HLI was created in apolipoprotein E-deficient mice by a two-stage surgical procedure. Five days after HLI was induced, mice were randomly allocated to receive metformin (n = 16; 300 mg/kg/day) or vehicle control (n = 15) by oral gavage for four weeks. The primary outcome was hind limb blood supply assessed by laser Doppler. Other outcomes included treadmill performance and molecular changes in the ischaemic limb. Metformin improved hind limb blood supply (P<0.001), but not physical performance, associated with increased phosphorylation of 5' adenosine monophosphate-activated protein kinase and endothelial nitric oxide synthase (P<0.05), reduced expression of thioredoxin interacting protein (P<0.05) and increased expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (P<0.05) in the ischaemic muscles and increased circulating nitric oxide levels (P<0.05). Metformin improved blood supply in a novel model of limb ischaemia associated with molecular changes previously linked with promoting angiogenesis, but these changes did not translate to improved physical performance. The findings suggest that laser Doppler hind limb blood supply may not be an ideal outcome measure to gauge the success of a drug in patients with PAD-related walking impairment.

There is an important gap of knowledge regarding the mechanisms behind the greater prevalence of chronic kidney disease (CKD) in females compared with males. Most of the published reports suggest that females are protected from acute kidney injury (AKI) and from the AKI-to-CKD transition; however, in this issue of Clinical Science, Moronge et al. demonstrate that female rats present with subclinical markers of kidney damage post-ischemic reperfusion injury despite normalized levels of plasma creatinine. These studies underscore the potential for this AKI-induced subclinical injury to underlie the higher sensitivity of females to develop CKD later in life.

Angiotensin II AT2 receptor (AT2R) activation leads to significant anti-fibrotic and anti-inflammatory effects in diseased organs, which has led to clinical trial evaluation of the AT2R agonist, Compound 21 (C21), as a treatment for idiopathic pulmonary fibrosis (IPF). In this study, the anti-fibrotic effects of a more selective AT2R ligand, β-Pro7 angiotensin III (β-Pro7 Ang III), with >20,000-fold affinity for the AT2R over the AT1R, were compared with that of C21 or the currently used IPF medication, pirfenidone, in mice with bleomycin (BLM)-induced pulmonary fibrosis. Adult female BALB/c mice received a double intranasal instillation of BLM (20 mg/kg/day) seven days apart and were maintained until day 35, while control mice were instilled with saline (SAL) seven days apart and maintained for the same time period. Sub-groups of BLM-injured mice were then treated on day 28 with vehicle (SAL), C21 (0.3 mg/kg/day) or β-Pro7 Ang III (0.1 mg/kg/day) via seven-day subcutaneously implanted osmotic minipumps, or daily from days 28 to 35 via orally administered pirfenidone (100 mg/kg/day). At day-35 post-injury, measures of lung fibrosis and compliance were evaluated. Compared with their SAL-instilled counterparts, SAL-treated BLM-injured mice presented with a significantly increased lung Ashcroft score, Masson's trichrome-stained and second harmonics generation-measured fibrosis, myofibroblast accumulation, and TGF-β1 expression, but reduced lung dynamic compliance at day-35 post-injury. While all treatments evaluated attenuated the BLM-induced lung myofibroblast accumulation and TGF-β1 expression, AT2R stimulation, but not pirfenidone, attenuated lung collagen deposition after seven days. β-Pro7 Ang III also significantly restored lung compliance and promoted collagen-degrading matrix metalloproteinase-2 activity. These findings highlighted the therapeutic value of selectively targeting the AT2R for treating IPF.

Abnormal fetal growth is associated with perinatal complications and adult disease. The placental mechanistic target of rapamycin (mTOR) signaling activity is positively correlated with placental nutrient transport and fetal growth. However, if this association represents a mechanistic link, it remains unknown. We hypothesized that trophoblast-specific Mtor knockdown in late pregnant mice decreases trophoblast nutrient transport and inhibits fetal growth. PiggyBac transposase-enhanced pronuclear injection was performed to generate transgenic mice containing a trophoblast-specific Cyp19I.1 promoter-driven, doxycycline-inducible luciferase reporter transgene with a Mtor shRNAmir sequence in its 3' untranslated region (UTR). We induced Mtor knockdown by administration of doxycycline starting at E14.5. Dams were killed at E 17.5, and trophoblastspecific gene targeting was confirmed. Placental mTOR protein expression was reduced in these animals, which was associated with a marked inhibition of mTORC1 and mTORC2 signaling activity. Moreover, we observed a decreased expression of System A amino acid transporter isoform SNAT2 and the System L amino acid transporter isoform LAT1 in isolated trophoblast plasma membranes and lower fetal, placental weight, and fetal:placental weight ratio. We also silence the MTOR in cultured primary human trophoblast cells, which inhibited the mTORC1 and C2 signaling, System A and System L amino acid transport activity, and markedly decreased the trafficking of LAT1 and SNAT2 to the plasma membrane. Inhibition of trophoblast mTOR signaling in late pregnancy is mechanistically linked to decreased placental nutrient transport and reduced fetal growth. Modulating trophoblast mTOR signaling may represent a novel intervention in pregnancies with abnormal fetal growth.