Thalidomide decreases high glucose-induced extracellular matrix protein synthesis in mesangial cells via the AMPK pathway

Protective effects of budesonide on LPS‑induced podocyte injury by modulating macrophage M1/M2 polarization: Evidence from in vitro and in silico studies

Budesonide (Bud), one of the most widely used lung medicines, is currently used as a repurposing medicine for immunoglobulin A nephropathy (IgAN) treatment. The progression of IgAN is related to inflammation involving macrophages and podocytes. The present study aimed to explore the effects of Bud on classically activated (M1)/alternatively activated (M2) macrophage polarization and podocyte injury under lipopolysaccharide (LPS)-induced inflammatory stress in vitro. Anti-inflammatory bioinformation of Bud was identified based on the Gene Expression Omnibus database. RAW264.7 cells were treated with normal medium, LPS, curcumin (Cur, positive control), or Bud 5, 10, or 20 µM. The expression levels of inducible nitric oxide synthase (iNOS), TNF-α, mannose receptor (CD206) and arginase (Arg)-1 were quantified by western blotting. The collected supernatants from macrophages were termed (Nor)MS, (LPS)MS, (Cur)MS and (Bud)MS. The TNF-α, IL-1β and nitric oxide (NO) levels in the supernatants were evaluated by ELISA and Griess assay. The podocytes were cultured in different supernatants and their survival rates were assessed by bromodeoxyuridine assay. TNF signaling is an important pathway by which Bud exerts anti-inflammatory activities. Compared with the LPS group, 5, 10 and 20 µM Bud significantly increased Arg-1 and decreased iNOS expression (Six: P<0.05) and 20 µM Bud significantly increased Arg-1 and CD206 and decreased iNOS and TNF-α expression (Four: P<0.05). Cur significantly decreased iNOS and TNF-α expression (Two: P<0.05). Compared with LPS, 5, 10 and 20 µM Bud and Cur significantly decreased TNF-α, IL-1β and NO levels (All: P<0.05). The podocyte survival rates of (Bud)MS and (Cur)MS were significantly higher than those of (LPS)MS (Four: P<0.05). The protective effect of Bud on podocyte injury is related to its modulation of M1/M2 polarization.

Thalidomide Mitigates Apoptosis via Endoplasmic Reticulum Stress in Diabetic Nephropathy

BACKGROUND

Previous studies have shown that endoplasmic reticulum (ER) stress is related to the apoptosis in the development of diabetic nephropathy (DN) and thalidomide (Thd) has renal-protective effects by suppressing inflammation and proliferation of MCs in DN. However, the effect of Thd on the apoptosis of MCs in DN remains largely unclear. The present research is designed to explore the effect of Thd on apoptosis in DN and the related mechanisms.

OBJECTIVE

The study is designed to examine the effect and mechanism of Thd on apoptosis in type 2 diabetic mice and high glucose (HG)-induced MCs.

METHOD

We first evaluated the ER stress markers and apoptosis-related proteins with the treatment of Thd in type 2 diabetic mice and MCs in vitro under HG conditions. MTT assay was used to assess cell viability. Additionally, we evaluated the effect of Thd treatment upon MC apoptosis through flow cytometry. Real-time polymerase chain reaction (RT-PCR) and Western blot were performed to evaluate genes and protein expression related to ER stress and apoptosis.

RESULTS

The levels of blood urea BUN, CREA, Urine albumin, and UACR in diabetic mice were significantly reduced after 8 weeks of intervention with Thd. And also, there were upregulated glucose-regulated protein 78 (GRP78), Caspase-12, and downregulated B-cell lymphoma 2 (Bcl-2) in glomeruli of DN mice. In vitro, compared with the HG group, MC apoptosis reduced dramatically with Thd treatment along with upregulation of Bcl-2 and downregulation of Bax. At the same time, ER stress markers GRP78, C/EBP homologous protein (CHOP), and Caspase-12 were also mitigated following the Thd treatment.

CONCLUSION

The present study indicates that Thd might reduce the ER stress in DN via downregulating of GRP78, CHOP, and Caspase12 expression, ultimately mitigating MCs apoptosis.

Thalidomide Exerts Anti-Inflammatory Effects in Cutaneous Lupus by Inhibiting the IRF4/NF-ҡB and AMPK1/mTOR Pathways

Thalidomide is effective in patients with refractory cutaneous lupus erythematosus (CLE). However, the mechanism of action is not completely understood, and its use is limited by its potential, severe side-effects. Immune cell subset analysis in thalidomide’s CLE responder patients showed a reduction of circulating and tissue cytotoxic T-cells with an increase of iNKT cells and a shift towards a Th2 response. We conducted an RNA-sequencing study using CLE skin biopsies performing a Therapeutic Performance Mapping System (TMPS) analysis in order to generate a predictive model of its mechanism of action and to identify new potential therapeutic targets. Integrating RNA-seq data, public databases, and literature, TMPS analysis generated mathematical models which predicted that thalidomide acts via two CRBN-CRL4A- (CRL4CRBN) dependent pathways: IRF4/NF-ҡB and AMPK1/mTOR. Skin biopsies showed a significant reduction of IRF4 and mTOR in post-treatment samples by immunofluorescence. In vitro experiments confirmed the effect of thalidomide downregulating IRF4 in PBMCs and mTOR in keratinocytes, which converged in an NF-ҡB reduction that led to a resolution of the inflammatory lesion. These results emphasize the anti-inflammatory role of thalidomide in CLE treatment, providing novel molecular targets for the development of new therapies that could avoid thalidomide’s side effects while maintaining its efficacy.

CircTLK1 Downregulation Attenuates High Glucose-Induced Human Mesangial Cell Injury by Blocking the AKT/NF-κB Pathway Through Sponging miR-126-5p/miR-204-5p

Diabetic nephropathy (DN) is the main cause of end-stage renal disease. Circular RNA hsa_circ_0004442 (circTLK1) accelerates the progression of renal cell carcinoma. However, the role of circTLK1 in DN pathogenesis is indistinct. The expression of circTLK1, microRNA-126-5p (miR-126-5p), and microRNA-204-5p (miR-204-5p) was tested by quantitative real-time polymerase chain reaction. The levels of interleukin-6 and interleukin-1β were measured by enzyme-linked immunosorbent assay. The levels of reactive oxygen species and malondialdehyde and the activity of superoxide dismutase were determined with corresponding kits. Several protein levels were evaluated with western blotting. The relationship between circTLK1 and miR-126-5p/miR-204-5p was verified by dual-luciferase reporter assay. CircTLK1 was highly expressed in DN patient's serum and high-glucose (HG)-treated human mesangial cells. Functionally, circTLK1 inhibition reduced HG-induced inflammation, oxidative stress, and ECM accumulation in human mesangial cells. CircTLK1 was verified as a sponge for miR-126-5p and miR-204-5p, which were downregulated in DN patient's serum and HG-treated human mesangial cells. Both miR-126-5p and miR-204-5p upregulation decreased inflammation, oxidative stress, and ECM accumulation in HG-treated human mesangial cells and circTLK1 silencing-mediated influence on HG-induced human mesangial cell injury was overturned by miR-126-5p or miR-204-5p inhibition. Moreover, circTLK1 knockdown blocked the AKT/NF-κB pathway by sponging miR-126-5p/miR-204-5p. CircTLK1 downregulation alleviated HG-induced inflammation, oxidative stress, and ECM accumulation through blocking the AKT/NF-κB pathway via sponging miR-126-5p/miR-204-5p, providing a new mechanism to comprehend the pathogenesis of DN.

Protective Effects of Two Safflower Derived Compounds, Kaempferol and Hydroxysafflor Yellow A, on Hyperglycaemic Stress-Induced Podocyte Apoptosis via Modulating of Macrophage M1/M2 Polarization

Objective

The primary initiating mechanism in diabetes nephropathy (DN) is hyperglycemia-induced inflammation in which macrophage and podocyte play important roles. The present research is aimed at exploring the effects of kaempferol (Ka) and hydroxysafflor yellow A (HSYA) on classically activated (M1)/alternatively activated (M2) macrophage polarization and podocyte apoptosis under hyperglycaemic conditions in vitro.

Methods

(1) RAW264.7 cells were treated with 11.1 mM glucose (NG), 33.3 mM glucose (HG), Ka 4-8 μM, and HSYA 100-200 μM separately. The expressions of inducible nitric oxide synthase (iNOS), tumor necrosis factor- (TNF-) α, mannose receptor (CD206), and arginase- (Arg-) 1 were quantified by Western blotting and real-time quantitative PCR. The collected supernatants from macrophage were named as (NG) MS, (HG) MS, (Ka) MS, and (HSYA) MS. (2) The podocyte survival rate was assessed by Bromodeoxyuridine assay, while TNF-α and interleukin- (IL-) 1β levels were evaluated by Elisa.

Results

(1) Compared to the HG group, the Ka and HSYA 100 μM groups decreased iNOS and TNF-α levels and increased Arg-1 and CD206 expressions significantly (protein and mRNA: p < 0.05, respectively). (2) The podocyte survival rate of Ka 8 μM was higher than that of HG, and the rates of (Ka) MS and (HSYA 100 μM) MS were higher than that of (HG) MS significantly (all: p < 0.05). (3) TNF-α and IL-1β levels of Ka and HSYA 100 μM were significantly lower than those of the HG group, and both levels in the (Ka) MS and (HSYA) MS were lower than those in the (HG) MS group significantly (p < 0.05, respectively).

Conclusion

The protective effects of Ka and HSYA on podocyte apoptosis under hyperglycemic stress are related to their modulation on M1/M2 polarization and the lowering effects on TNF-α and IL-1β levels.

Protective Effects of Thalidomide on High-Glucose-Induced Podocyte Injury through In Vitro Modulation of Macrophage M1/M2 Differentiation

Objective. It has been shown that podocyte injury represents an important pathological basis that contributes to proteinuria and eventually leads to kidney failure. High glucose (HG) activates macrophage polarization, further exacerbating HG-induced podocyte injury. Our previous study on diabetic nephropathy rats indicated that thalidomide (Tha) has renoprotective properties. The present study explored the effects of Tha on mRNA and protein expressions of inducible nitric oxide synthase (iNOS), tumor necrosis factor- (TNF-) α, mannose receptor (CD206), and arginase- (Arg-) 1 in HG-activated macrophages. iNOS and TNF-α are established as markers of classically activated macrophage (M1). CD206 and Arg-1 are regarded as markers of alternatively activated macrophages (M2). During the experiment, the supernatants of (HG)-treated and (Tha)-treated macrophages, designated as (HG) MS and (Tha) MS, were simultaneously collected and processed. TNF-α and interleukin- (IL-) 1β levels as well as protein expressions of nephrin and podocin in HG, (HG) MS, and (Tha) MS-cultured podocytes were evaluated. The results showed that compared to the 11.1 mM normal glucose (NG), the 33.3 mM HG-cultured RAW 264.7 cells exhibited upregulated iNOS and TNF-α mRNAs and protein expressions, and downregulated CD206 and Arg-1 expressions significantly (p < 0.05). Tha 200 μg/ml suppressed iNOS and TNF-α, and promoted CD206 and Arg-1 expressions significantly compared to the HG group (p < 0.05). Furthermore, (HG) MS-treated podocytes showed an increase in TNF-α and IL-1β levels and a downregulation in nephrin and podocin expression significantly compared to NG-treated and HG-treated podocytes (p < 0.05). The (Tha 200 μg/ml) MS group exhibited a decrease in TNF-α and IL-1β level, and an upregulation in nephrin and podocin expressions significantly compared to the (HG) MS group (p < 0.05). Our research confirmed that HG-activated macrophage differentiation aggravates HG-induced podocyte injury in vitro and the protective effects of Tha might be related to its actions on TNF-α and IL-1β levels via its modulation on M1/M2 differentiation.