Peroxisome proliferator activated receptor-α (PPAR-α) is significantly expressed in various tissues such as the liver, kidney, myocardium, and skeletal muscle, which plays a central role in the development of various diseases by regulating key physiological processes such as energy homeostasis, redox balance, inflammatory response, and ferroptosis. As an important metabolic and excretory organ of the body, renal dysfunction can lead to water and electrolyte imbalance, toxin accumulation, and multiple system complications. The causes of kidney injury are complex and diverse, including acute injury factors (such as ischemia/reperfusion, nephrotoxic drugs, septic shock, and immune glomerulopathy), as well as chronic progressive causes [such as metabolic disease-related nephropathy, hypertensive nephropathy (HN)], and risk factors such as alcohol abuse, obesity, and aging. This review briefly describes the structure, function, and activity regulation mechanism of PPAR-α, systematically elucidates the molecular regulatory network of PPAR-α in the pathological process of kidney injury including acute kidney injury (AKI) such as renal ischemia/reperfusion injury (IRI), drug-induced AKI, sepsis-associated acute kidney injury (SA-AKI), glomerulonephritis, chronic kidney disease (CKD) such as diabetic nephropathy (DN), HN, and other kidney injury, and summarizes the mechanisms related to PPAR-α regulation of kidney injury, including regulation of metabolism, antioxidation, anti-inflammation, anti-fibrosis, and anti-ferroptosis. This review also evaluates PPAR-α's medical value as a novel therapeutic target, and aims to provide theoretical basis for the development of kidney protection strategies based on PPAR-α targeted intervention.
Humans ; PPAR alpha/metabolism* ; Acute Kidney Injury/therapy* ; Animals ; Kidney/metabolism*

The interaction of gut microbiota and its metabolites with the host not only plays an important role in maintaining gut homeostasis and host health, but also is a key link in responding to pathogen infections. A thorough understanding of the changes in gut microbiota and its metabolites during infection, as well as their role and mechanism in host defense against infection, is helpful to guide anti-infection treatment. This review focuses on the role of gut microbiota and their metabolites in host defense against bacterial, fungal, and viral infections, and reveals that they can exert anti-infection effects through resistance mechanisms (inducing antimicrobial substances, training immunity, inhibiting pathogen respiration, directly neutralizing pathogens, immune regulation) and tolerance mechanisms (altering energy metabolism patterns of microbiota, cell proliferation and tissue damage repair, maintaining physiological signal transduction in extraintestinal organs, inflammation regulation, maintaining the integrity of the intestinal barrier), and also summarizes measures to regulate gut microbiota against pathogen infections, in order to provide more ideas for novel anti-infection prevention and treatment strategies targeting gut microbiota and its metabolites.

Infection is a common medical problem at present. Different pathogens can lead to different infections. Severe infections can ultimately lead to sepsis, resulting in multiple organ dysfunction and the high mortality of patients. Therefore, studying the occurrence and development of severe infections is essential to improve the survival rate of patients. More and more studies have revealed the important role of connection between intestine and liver in infectious diseases. The maintenance of intestinal mechanical barrier and biological barrier function and the regulation of intestinal flora metabolites can reduce infectious liver injury. Bile acids are important metabolites in the liver, which can inhibit the progression of certain infectious intestinal injuries and promote intestinal damage caused by certain pathogens. In this article, the mechanism of action of the intestinal-liver axis in infection was reviewed to find a new target for the treatment of clinical infection.

Objective:To explore the effects of neutrophilic granule protein (NGP) on the expression of lipocalin 2 (LCN2) in inflammatory macrophages and its mechanism.Methods:NGP-high-expressed RAW264.7 cells (NGP/RAW cells) and negative control RAW264.7 cells (NC/RAW cells) were cultured in vitro. Primary peritoneal macrophages of NGP-high-expressed mice and wild-type C57BL/6 mice were extracted, then cultured in vitro. The cell inflammatory model was established by stimulating with 10 mg/L lipopolysaccharide (LPS, LPS group), and the phosphate buffer solution (PBS) control group was set up. Enzyme-linked immunosorbent assay (ELISA) was used to detect the level of LCN2 in different types of cells. The protein expression of phosphorylated signal transduction and activator of transcription 1 (p-STAT1) was detected with Western blotting. Other NGP/RAW cells and NC/RAW cells were treated with 10 mg/L LPS, 5 mg/L STAT1 pathway inhibitor (fludarabine)+10 mg/L LPS, respectively. The PBS control group was set up. ELISA was used to detect the level of LCN2. Results:In different types of cells, the levels of LCN2 were increased significantly after LPS stimulation in the LPS group as compared with those in the PBS control group, and peaked at 24 hours (μmol/L: 25.61±1.02 vs. 0.46±0.02 in NC/RAW cells, 74.51±2.14 vs. 0.25±0.04 in NGP/RAW cells, 10.13±0.22 vs. 0.01±0.01 in primary macrophages of wild-type C57BL/6 mice, 28.35±0.61 vs. 0.08±0.01 in primary macrophages of NGP-high-expressed mice, all P < 0.05), indicating that the expression of LCN2 in macrophages altered during inflammation reaction. The level of LCN2 in NGP/RAW cells was found significantly increased at different time points after LPS stimulation comparing with that in NC/RAW cells (μmol/L: 8.32±0.22 vs. 3.12±0.11 at 6 hours, 23.12±0.86 vs. 8.12±0.32 at 12 hours, 74.51±2.14 vs. 25.61±1.02 at 24 hours, all P < 0.05), along with the expression of p-STAT1 was significantly up-regulated. The level of LCN2 in the primary macrophages of NGP-high-expressed mice was also significantly increased at 24 hours after LPS stimulation comparing with that in the primary macrophages of wild-type C57BL/6 mice (μmol/L: 28.35±0.61 vs. 10.13±0.22, P < 0.05). However, after pretreated with STAT1 pathway inhibitors, the production of LCN2 in NGP/RAW cells was decreased significantly comparing with that in the LPS group (μmol/L: 6.81±0.19 vs. 22.54±0.58, P < 0.05). But the inhibitors had no significant effect on LCN2 production in NC/RAW cells showing no significant difference as compared with LPS group (μmol/L: 8.04±0.20 vs. 7.86±0.15, P > 0.05), indicating that NGP could up-regulate the expression of LCN2 in macrophages stimulated by LPS by promoting STAT1 activation. Conclusion:NGP could positively regulate LCN2 expression in inflammatory macrophages by activating STAT1 pathway.

BACKGROUND: The presence of fibrosis is a criterion for subtype classification in the newly updated hypersensitivity pneumonitis (HP) guidelines. The present study aimed to summarize differences in clinical characteristics and prognosis of non-fibrotic hypersensitivity pneumonitis (NFHP) and fibrotic hypersensitivity pneumonitis (FHP) and explore factors associated with the presence of fibrosis. METHODS: In this prospective cohort study, patients diagnosed with HP through a multidisciplinary discussion were enrolled. Collected data included demographic and clinical characteristics, laboratory findings, and radiologic and histopathological features. Logistic regression analyses were performed to explore factors related to the presence of fibrosis. RESULTS: A total of 202 patients with HP were enrolled, including 87 (43.1%) NFHP patients and 115 (56.9%) FHP patients. Patients with FHP were older and more frequently presented with dyspnea, crackles, and digital clubbing than patients with NFHP. Serum levels of carcinoembryonic antigen, carbohydrate antigen 125, carbohydrate antigen 153, gastrin-releasing peptide precursor, squamous cell carcinoma antigen, and antigen cytokeratin 21-1, and count of bronchoalveolar lavage (BAL) eosinophils were higher in the FHP group than in the NFHP group. BAL lymphocytosis was present in both groups, but less pronounced in the FHP group. Multivariable regression analyses revealed that older age, <20% of lymphocyte in BAL, and ≥1.75% of eosinophil in BAL were risk factors for the development of FHP. Twelve patients developed adverse outcomes, with a median survival time of 12.5 months, all of whom had FHP. CONCLUSIONS Older age, <20% of lymphocyte in BAL, and ≥1.75% of eosinophil in BAL were risk factors associated with the development of FHP. Prognosis of patients with NFHP was better than that of patients with FHP. These results may provide insights into the mechanisms of fibrosis in HP.
Humans ; Bronchoalveolar Lavage Fluid ; Prospective Studies ; Alveolitis, Extrinsic Allergic/diagnosis* ; Fibrosis ; Carbohydrates

Photohardening therapy, also known as photodesensitization therapy, refers to the phototherapy and photochemotherapy of idiopathic actinic dermatoses, and its goal is to improve the patients′ tolerance to sunlight and prevent disease flares. Its mechanisms of action involve a variety of cellular and inflammatory factors. This therapy is suitable for all idiopathic actinic dermatoses, with definite efficacy and good safety. However, the treatment specificity usually leads to poor compliance. The development of UVA1 rush hardening and home phototherapy is expected to solve this problem.

Objective:To investigate serum lipidomic profiles in patients with chronic actinic dermatitis (CAD), and to search for biomarkers of CAD.Methods:A retrospective analysis was conducted. Serum samples were collected from 46 patients with CAD and 16 age- and gender-matched healthy controls in the Guangzhou Institute of Dermatology from April 2011 to December 2021. Changes in serum lipid composition and expression were assessed by liquid chromatography-mass spectrometry. Principal component analysis, partial least squares discriminant analysis, and orthogonal partial least squares discriminant analysis were performed to screen differential biomarkers, and receiver operating characteristic (ROC) curve analysis was conducted to screen diagnostic markers. Comparisons of the age and gender distribution between groups were performed using t test and chi-square test, respectively. Results:The 46 CAD patients were aged from 30 to 84 (60.39 ± 10.52) years, including 41 males and 5 females; the 16 healthy controls were aged from 50 to 89 (59.81 ± 10.72) years, including 14 males and 2 females; there were no significant differences in the age or gender distribution between the two groups (age: t = 0.19, P = 0.853; gender: χ2 = 0.03, P = 0.859). Totally, 4 136 lipid molecules belonging to 40 subclasses were identified in the serum samples from CAD patients as well as healthy controls. Twenty-two differential lipid molecules were identified between the CAD patients and healthy controls, belonging to 9 subclasses (triglycerides, sphingomyelin, phosphatidylserine, phosphatidylethanolamine, monofatty acid glycerides, lysophosphatidylcholine, hexose ceramide, diglycerides, and cardiolipin). When the combinations of triglycerides (37.7e) and Na, those of monoglycerides (22.3) and NH 4, or those of phosphatidylserine (18.0_18.1) and H served as diagnostic markers separately, the areas under the ROC curve (AUCs) were all > 0.8, and the AUCs of 16 differential lipid molecules were all > 0.7. Conclusion:The serum lipid composition differed between healthy controls and CAD patients, and the combinations of triglycerides (37.7e) and Na, those of monoglycerides (22.3) and NH 4, and those of phosphatidylserine (18.0_18.1) and H may be promising biomarkers for the diagnosis of CAD.

Objective:To evaluate the effect of metformin on ultraviolet A (UVA) -induced photoaging of an immortalized human keratinocytes cell line (HaCaT), and to explore its potential mechanisms.Methods:Cell counting kit 8 (CCK8) assay was performed to evaluate the effect of metformin at different concentrations (0 - 100 mmol/L) on the viability of HaCaT cells, and 10 mmol/L metformin was selected for subsequent experiments. Cultured HaCaT cells were divided into a blank control group (conventional culture), a metformin group (treated with culture medium containing 10 mmol/L metformin), a UVA irradiation group (conventional culture for 24 hours followed by 10 J/cm 2 UVA irradiation) and a metformin + UVA group (treated with culture medium containing 10 mmol/L metformin for 24 hours followed by 10 J/cm 2 UVA irradiation) ; UVA irradiation was performed at a dose of 10 J/cm 2 once a day for 3 consecutive days. After 4-day treatment, cells were collected, the β-galactosidase assay was performed to determine the proportion of senescent cells in each group, 2′, 7′-dichlorodihydrofluorescein diacetate assay to detect levels of intracellular reactive oxygen species (ROS), and the comet assay to detect DNA damage levels. Additionally, some HaCaT cells were divided into the blank control group, metformin group, 1.25 μmol/L dorsomorphin (an adenosine monophosphate-activated protein kinase [AMPK] inhibitor) + metformin group, and 2.5 μmol/L dorsomorphin + metformin group, and cells in the latter two groups were treated with 1.25 and 2.5 μmol/L dorsomorphin respectively for 2 hours, followed by the treatment with 10 mmol/L metformin for 24 hours. Western blot analysis was performed to determine the cellular localization and phosphorylation levels of nuclear factor-erythroid 2-related factor 2 (Nrf2). By using the small-interfering RNA (siRNA) -mediated silencing method, siRNA-Nrf2 was transfected into HaCaT cells to knock down Nrf2 expression (siRNA-Nrf2 group) ; 2.5 μmol/L dorsomorphin-treated HaCaT cells or Nrf2-knockdown HaCaT cells were treated with metformin and UVA irradiation (dorsomorphin + metformin + UVA group, siRNA-Nrf2 + metformin + UVA group, respectively), and the proportions of senescent cells were further calculated in each group. Statistical analysis was carried out by using one-way analysis of variance and two-way analysis of variance, and least significant difference (LSD) - t test was used for multiple comparisons. Results:Treatment with different concentrations of metformin for 24 hours could affect the viability of HaCaT cells to varying degrees ( F = 5 206.31, P < 0.001) ; there were no significant differences in the relative survival rates of HaCaT cells between the 10 - 20 mmol/L metformin groups and the control group (0 mmol/L metformin group, all P > 0.05), while the relative cell survival rates were significantly lower in the 25 - 100 mmol/L metformin groups than in the control group (all P < 0.05). After UVA irradiation, HaCaT cells shrank significantly and became narrow and elongated, and the intercellular spaces increased; the relative cell survival rate was significantly lower in the UVA irradiation group (76.13% ± 1.03%) than in the blank control group (100.00% ± 1.24%, LSD- t = 14.86, P < 0.001), but significantly higher in the metformin + UVA group (106.69% ± 2.45%) than in the UVA irradiation group (LSD- t = 11.55, P < 0.001). Moreover, the UVA irradiation group showed significantly increased proportions of senescent cells (45.14% ± 4.98%), intracellular ROS levels (144.61% ± 4.91%), and percentages of DNA in the tail (75.33% ± 1.77%) compared with the blank control group (23.84% ± 1.89%, 55.49% ± 1.57%, 1.88% ± 0.29%, respectively, all P < 0.001), while the metformin + UVA group showed significantly decreased proportions of senescent cells (24.26% ± 1.34%), intracellular ROS levels (58.62% ± 2.17%), percentages of DNA in the tail (15.83% ± 1.23%) compared with the UVA irradiation group (all P < 0.001). Western blot analysis showed that the Nrf2 expression in the cytoplasm was lower in the 10 mmol/L metformin group than in the blank control group, while the phosphorylated Nrf2 expression in the nuclei was higher in the 10 mmol/L metformin group than in the blank control group, suggesting that metformin could effectively induce the phosphorylation of Nrf2 and its nuclear translocation; both the pretreatment with 1.25 and 2.5 μmol/L dorsomorphin could significantly reduce the phosphorylation levels of AMPKα and Nrf2 induced by 10 mmol/L metformin. The proportions of senescent cells in the dorsomorphin + metformin + UVA group and the siRNA-Nrf2 + metformin + UVA group were 67.84% ± 2.74% and 65.94% ± 1.33%, respectively, which were significantly higher than those in the metformin + UVA group (37.76% ± 1.64%, t = 14.45, 13.34, respectively, both P < 0.001) . Conclusion:Metformin may inhibit UVA-induced photoaging of HaCaT cells by activating the AMPK/Nrf2 signaling pathway, scavenging ROS and reducing DNA damage.

Objective:To explore the effect and mechanism of cytochrome P450 1A1 (CYP1A1) on regulating phagocytosis of macrophage treated with Escherichia coli ( E.coli). Methods:① The mouse leukemia cells lines of monocyte macrophage RAW264.7 (RAW) were cultured in vitro and treated with 30 multiplicity of infection (MOI) dosages of E.coli for 40 minutes, glycerin control group was set up to observe the change of CYP1A1 during infection. ② The RAW cells with CYP1A1 overexpression (CYP1A1/RAW) and knock out (CYP1A1 KO/RAW) were cultured in vitro and treated with 30 MOI E. coli for 40 minutes, while the negative controlled RAW cells (NC/RAW) were established as control to observe the relationship between cell phagocytosis and CYP1A1 expression, and the effect of CYP1A1 on phagocytic receptor [scavenger receptor-A (SR-A)] and its signal pathway [mitogen-activated protein kinase (MAPK) pathway]. ③ NC/RAW and CYP1A1 KO/RAW cells were cultured in vitro and pretreated with 1 μmol/L extracellular signal-regulated kinase (ERK) inhibitor (U0126) for 2 hours, and then treated with 30 MOI E.coli for 40 minutes, phosphate buffered solution (PBS) control group was set up to observe whether the effect of CYP1A1 on phagocytosis through controlled the MAPK pathway. ④ The RAW cells were cultured in vitro and pretreated with 100 nmol/L CYP1A1 hydroxylase active product 12(S)-hydroxyeicosatetraenoic acid [12(S)-HETE] for 2 hours, and then treated with 30 MOI E.coli for 40 minutes, and PBS control group was set up to observe whether the effect of CYP1A1 on phagocytosis was related to CYP1A1 hydroxylating metabolite. ⑤ The RAW cells with overexpression CYP1A1 hydroxylase-activity mutation (CYP1A1m/RAW) were cultured in vitro and treated with 30 MOI E.coli for 40 minutes, the CYP1A1/RAW cells were set up as control group to observe whether the effect of CYP1A1 on phagocytosis was related to CYP1A1 hydroxylase-activity. Results:① Compared with glycerin control group, CYP1A1 mRNA expression was significantly increased by E.coli stimulation (2 -ΔΔCt: 7.79±0.71 vs. 1.00±0.00, P < 0.05), indicating that CYP1A1 might participate in regulating infection progress. ② Compared with NC/RAW cells, the number of E.coli colonies phagocytized by CYP1A1/RAW cells was significantly decreased after 40 minutes of E.coli stimulation (×10 3 CFU/mL: 4.67±3.06 vs. 15.67±5.03, P < 0.05), while CYP1A1 KO/RAW cells had a significant increase in the number of E.coli colonies phagocytized (×10 3 CFU/mL: 46.00±5.29 vs. 15.67±5.03, P < 0.05), suggesting that CYP1A1 might negatively control macrophage phagocytosis function. Meanwhile, compared with NC/RAW cells, the expression of SR-A mRNA in CYP1A1/RAW cells was significantly down-regulated (2 -ΔΔCt: 0.31±0.03 vs. 1.00±0.00, P < 0.05), and the activation level of ERK was significantly reduced. However, the expression of SR-A mRNA in CYP1A1 KO/RAW cells was significantly up-regulated (2 -ΔΔCt: 3.74±0.25 vs. 1.00±0.00, P < 0.05), and the activation of ERK was enhanced, indicating that CYP1A1 could negatively regulate phagocytic receptors and their signaling pathways.③ Compared with PBS, U0126 pretreatment significantly inhibited the CYP1A1 knockout induced upregulation of SR-A mRNA expression (2 -ΔΔCt: 0.62±0.05 vs. 4.38±0.39, P < 0.05) and ERK activation, and inhibited the enhancement of phagocytosis in macrophages induced by CYP1A1 knock out [ E.coli colonies phagocytized by cells (×10 3 CFU/mL): 12.67±1.15 vs. 45.33±4.16, P < 0.05], suggesting that CYP1A1 inhibited macrophage phagocytosis function by regulating ERK activation. ④ Compared with PBS, the phagocytosis of RAW cells pretreated with 12(S)-HETE did not change significantly [ E.coli colonies phagocytized by cells (×10 3 CFU/mL): 17.00±1.00 vs. 16.33±2.52, P > 0.05], suggesting that CYP1A1 might not control phagocytosis function by its hydroxylase-activity metabolism 12(S)-HETE. ⑤ Compared with CYP1A1/RAW cells, there was no significant change in the phagocytic function of CYP1A1m/RAW cells [ E.coli colonies phagocytized by cells (×10 3 CFU/mL): 3.67±1.15 vs. 3.33±0.58, P > 0.05], suggesting that CYP1A1 might not control phagocytosis function by its hydroxylase-activity. Conclusion:CYP1A1 can negatively regulate the phagocytosis of macrophages by inhibiting the activation of ERK and reducing the expression of SR-A, but this regulatory effect is not related to the activity of CYP1A1 hydroxylase and its pro-inflammatory metabolism 12(S)-HETE.

Humans ; Asthma/drug therapy* ; Biological Therapy