Discrimination of skin sensitizers from non‐sensitizers by interleukin‐1α and interleukin‐6 production on cultured human keratinocytes

In vitro testing methods for classifying sensitizers could be valuable alternatives to in vivo sensitization testing using animal models, such as the murine local lymph node assay (LLNA) and the guinea pig maximization test (GMT), but there remains a need for in vitro methods that are more accurate and simpler to distinguish skin sensitizers from non‐sensitizers. Thus, the aim of our study was to establish an in vitro assay as a screening tool for detecting skin sensitizers using the human keratinocyte cell line, HaCaT. HaCaT cells were exposed to 16 relevant skin sensitizers and 6 skin non‐sensitizers. The highest dose used was the dose causing 75% cell viability (CV75) that we determined by an MTT [3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide] assay. The levels of extracellular production of interleukin‐1α (IL‐1α) and IL‐6 were measured. The sensitivity of IL‐1α was 63%, specificity was 83% and accuracy was 68%. In the case of IL‐6, sensitivity: 69%, specificity: 83% and accuracy: 73%. Thus, this study suggests that measuring extracellular production of pro‐inflammatory cytokines IL‐1α and IL‐6 by human HaCaT cells may potentially classify skin sensitizers from non‐sensitizers. Copyright © 2015 John Wiley & Sons, Ltd.     

Protective effects of β‐sheet breaker α/β‐hybrid peptide against amyloid β‐induced neuronal apoptosis in vitro

Alzheimer's disease is most common neurodegenerative disorder and is characterized by increased production of soluble amyloid‐β oligomers, the main toxic species predominantly formed from aggregation of monomeric amyloid‐β (Aβ). Increased production of Aβ invokes a cascade of oxidative damages to neurons and eventually leads to neuronal death. This study was aimed to investigate the neuroprotective effects of a β‐sheet breaker α/β‐hybrid peptide (BSBHp) and the underlying mechanisms against Aβ₄₀‐induced neurotoxicity in human neuroblastoma SH‐SY5Y cells. Cells were pretreated with the peptide Aβ₄₀ to induce neurotoxicity. Assays for cell viability, cell membrane damage, cellular apoptosis, generation of reactive oxygen species (ROS), intracellular free Ca²⁺, and key apoptotic protein levels were performed in vitro. Our results showed that pretreatment with BSBHp significantly attenuates Aβ₄₀‐induced toxicity by retaining cell viability, suppressing generation of ROS, Ca²⁺ levels, and effectively protects neuronal apoptosis by suppressing pro‐apoptotic protein Bax and up‐regulating antiapoptotic protein Bcl‐2. These results suggest that α/β‐hybrid peptide has neuroprotective effects against Aβ₄₀‐induced oxidative stress, which might be a potential therapeutic agent for treating or preventing neurodegenerative diseases.     

Estrogen and ERα enhanced β‐catenin degradation and suppressed its downstream target genes to block the metastatic function of HA22T hepatocellular carcinoma cells via modulating GSK‐3β and β‐TrCP expression

In our previous experiments, we found β‐catenin was highly expressed in the tumor area with high invasive ability and poor prognosis. In this study, we have examined the mechanism by which ERα regulates β‐catenin expression as well as the metastasis ability of hepatocellular cancer HA22T cells. To identify whether the anticancer effect of estrogen and ERα is mediated through suppression of β‐catenin expression, we co‐transfected pCMV‐β‐catenin and ERα into HA22T cells, and determined the cell motility by wound healing, invasion, and migration assays. Results showed that estrogen and/or ERα inhibited β‐catenin gene expression and repressed HA22T cell motility demonstrated that similar data was observed in cells expressing the ERα stable clone. Moreover, we examined the protein‐protein interaction between ERα and β‐catenin by immunostain, co‐immunoprecipitation, and Western blotting. E2 enhanced the binding of ERα with β‐catenin and then triggered β‐catenin to bind with E3 ligase (βTrCP) to promote β‐catenin degradation. Finally by employing systematic ChIP studies, we showed ERα can interact directly with the β‐catenin promoter region following E2 treatment. All our results reveal that estrogen and ERα blocked metastatic function of HA22T cells by modulating GSK3β and βTrCP expression and further enhanced β‐catenin degradation and suppressed its downstream target genes. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 519–529, 2017.     

Synthesis,crystal structure and molecular conformation of Nα‐Boc‐l‐leucyl‐(Z)‐β‐(3‐pyridyl)‐α,β‐ dehydroalanyl‐l‐leucine methyl ester*

Abstract: A protected tridehydropeptide containing (Z)‐β‐(3‐pyridyl)‐α,β‐dehydroalanine (Δ^Z3Pal) residue, Boc‐Leu‐Δ^Z3Pal‐Leu‐OMe ( 1 ), was synthesized via Erlenmeyer azlactone method. X‐ray crystallographic analysis revealed that the peptide 1 adopts an extended conformation, which is similar to that of a Δ^ZPhe analog, Boc‐Leu‐Δ^ZPhe‐Leu‐OMe ( 2 ).     

The Proteolytic Stability and Cytotoxicity Studies of l‐Aspartic Acid and l‐Diaminopropionic Acid derived β‐Peptides and a Mixed α/β‐Peptide

The use of peptides as drugs in pharmaceutical applications is hindered by their susceptibility to proteolysis and therefore low bioavailability. β‐Peptides that contain an additional methylene group in the backbone, are gaining recognition from a pharmaceutical stand point as they are considerably more resilient to proteolysis and metabolism. Recently, we reported two new classes of β ‐peptides, β ³‐ and β²‐peptides derived from l ‐aspartic acid and l ‐diaminopropionic acid, respectively. Here, we report the proteolytic stability of these β‐peptidic compounds and a mixed α /β‐peptide against three enzymes (pronase, trypsin and elastase), as well as, human serum. The stability of these peptides was compared to an α‐peptide. Peptides containing β‐linkages were resistant to all conditions. The mixed α /β‐peptide, however, exhibited proteolysis in the presence of trypsin and pronase but not elastase. The rate of degradation of the mixed α /β‐peptide was slower than that would be expected for an α‐peptide. In addition, these β‐peptides were not toxic to HeLa and COS‐1 cell lines as observed by MTT cytotoxicity assay. These results expand the scope of mixed α /β‐peptides containing β‐amino acids or small β‐peptide fragments as therapeutic peptides.     

Agonist function of the recombinant α4β3δ GABAA receptor is dependent on the human and rat variants of the α4‐subunit

1. It is known that the α₄‐subunit is likely to occur in the brain predominantly in α₄β₃δ receptors at extrasynaptic sites. Recent studies have revealed that the α₁‐, α₄‐, γ₂‐ and δ‐subunits may colocalize extrasynaptically in dentate granule cells of the hippocampus. In the present study, we characterized a series of recombinant GABA_A receptors containing human (H) and rat (R) α₁/α₄‐, β₂/β₃‐ and γ_2S/δ‐subunits in Xenopus oocytes using the two‐electrode voltage‐clamp technique. 2. Both Hα₁β₃δ and Hα₄β₃γ_2S receptors were sensitive to activation by GABA and pentobarbital. Contrary to earlier findings that the α₄β₃δ combination was more sensitive to agonist action than the α₄β₃γ_2S receptor, we observed extremely small GABA‐ and pentobarbital‐activated currents at the wild‐type Hα₄β₃δ receptor. However, GABA and pentobarbital activated the wild‐type Rα₄β₃δ receptor with high potency (EC₅₀ = 0.5 ± 0.7 and 294 ± 5 μmol/L, respectively). 3. Substituting the Hα₄ subunit with Rα₄ conferred a significant increase in activation on the GABA and pentobarbital site in terms of reduced EC₅₀ and increased I_max. When the Hα₄ subunit was combined with the Rβ₃ and Rδ subunit in a heteropentameric form, the amplitude of GABA‐ and pentobarbital‐activated currents increased significantly compared with the wild‐type Hα₄β₃δ receptor. 4. Thus, the results indicate that the Rα₄β₃δ, Hα₁β₃δ and Hα₄β₃γ_2S combinations may contribute to functions of extrasynaptic GABA_A receptors. The presence of the Rα₄ subunit at recombinant GABA_A receptors containing the δ‐subunit is a strong determinant of agonist action. The recombinant Hα₄β₃δ receptor is a less sensitive subunit composition in terms of agonist activation.     

GRK2/β‐arrestin mediates arginine vasopressin‐induced cardiac fibroblast proliferation

Cardiac fibrosis is a pathological feature commonly found in hearts exposed to haemodynamic orneurohormonal stress. Elevated levels of arginine vasopressin (AVP) are closely associated with the progression of heart failure and could be an underlying cause of cardiac fibrosis. The aim of this study is to characterize the effect of AVP on neonatal rat cardiac fibroblasts (NRCFs) and to illustrate its signalling mechanism. The proliferative effect of AVP was assessed by methylthiazolyldiphenyl‐tetrazolium assay and 5‐bromo‐2′‐deoxyuridine (BrdU) incorporation assay, and the amounts of cellular signalling proteins α‐smooth muscle actin (α‐SMA), matrix metalloproteinase (MMP) 2, MMP9, and phosphorylated ERK_1/2 were determined by western blotting. AVP, in a time‐ and concentration‐dependent manner, promoted NRCF proliferation and the expression of MMP2 and MMP9. Inhibition of G protein‐coupled receptor kinase2 (GRK2) by the inhibitory peptide GRK2‐Ct or knock‐down of GRK2 suppressed AVP‐induced BrdU incorporation and the expression of MMP2 and α‐SMA in NRCFs. Moreover, shRNA‐mediated silencing of β‐arrestin1 or β‐arrestin 2 abolished AVP‐induced BrdU incorporation and MMP2 expression. AVP‐induced NRCF proliferation depended on the phosphorylation of ERK_1/2, and inhibition of GRK2 or silencing of β‐arrestins blocked AVP‐induced ERK_1/2 phosphorylation. The effects of AVP on NRCF proliferation and α‐SMA expression were blocked by SR45059, a vasopressin receptor type1A (V_1AR) selective antagonist. In conclusion, AVP promotes NRCF proliferation through V_1AR‐mediated GRK2/β‐arrestin/ERK_1/2 signalling.     

Synthesis of Novel Pyrimidin‐4‐One Bearing Piperazine Ring‐Based Amides as Glycogen Synthase Kinase‐3β Inhibitors with Antidepressant Activity

Novel pyrimidin‐4‐one derivatives have been synthesized using EDC coupling and evaluated as glycogen synthase kinase‐3β (GSK‐3β) inhibitors. Among all the synthesized compounds, compound 5 (3‐methyl‐6‐phenyl‐2‐(piperazin‐1‐yl)‐3,4‐dihydropyrimidin‐4‐one) exhibited the most potent inhibitory activity against GSK‐3β with IC₅₀ value of 74 nm . The molecular docking studies were performed to elucidate the binding modes of the compounds with the target, and a crucial interaction involving hydrogen bond formation with Val‐135 to the active site of GSK‐3β was observed. Furthermore, the synthesized compounds were subjected to in vivo evaluation of their antidepressant activity, and compound 5 showing highest inhibition of GSK‐3β was also found to significantly reduce the duration of immobility at 50 mg/kg, when compared with fluoxetine, a known antidepressant drug. The results of our study suggest that compound 5 may serve as a valuable template for the design and development of inhibitors of GSK‐3β with antidepressant activity.     

Stevioside protects against rhabdomyolysis‐induced acute kidney injury through PPAR‐γ agonism in rats

We explored the potential role of peroxisome proliferator activated receptor‐γ (PPAR‐γ) in stevioside‐mediated renoprotection using rhabdomyolysis‐induced acute kidney injury (AKI) model in rats. Rhabdomyolysis refers to intense skeletal muscle damage, which further causes AKI. Glycerol (50% w/v, 8 ml/kg) was injected intramuscularly in rats to induce rhabdomyolysis. After 24 hr, AKI was demonstrated by quantifying serum creatinine, urea, creatinine clearance, microproteinuria, and electrolytes in rats. Further, oxidative stress was measured by assaying thiobarbituric acid reactive substances, generation of superoxide anion, and reduced glutathione levels. Additionally, serum creatine kinase (CK) level was assayed to determine glycerol‐induced muscle damage in rats. Pathological changes in rat kidneys were studied using hematoxylin–eosin and periodic acid Schiff staining. Moreover, the expression of apoptotic markers (Bcl‐2, Bax) in rat kidneys was demonstrated by immunohistochemistry. Stevioside (10, 25, and 50 mg/kg) was administered to rats, prior to the induction of AKI. In a separate group, bisphenol A diglycidyl ether (BADGE, 30 mg/kg), a PPAR‐γ receptor antagonist was given prior to stevioside administration, which was followed by rhabdomyolysis‐induced AKI in rats. The significant alteration in biochemical and histological parameters in rats indicated AKI, which was attenuated by stevioside treatment. Pretreatment with BADGE abrogated stevioside‐mediated renoprotection, which is suggestive of the involvement of PPAR‐γ in its renoprotective effect. In conclusion, stevioside protects against rhabdomyolysis‐induced AKI, which may be attributed to modulation of PPAR‐γ expression.     

Radiosynthesis of the α4β2 nicotinic acetylcholine receptor ligand: 5‐((1‐[11C]‐methyl‐2‐(S)‐pyrrolidinyl)methoxy)‐2‐chloro‐3‐((E)‐2‐(2‐fluoropyridin‐4‐yl)vinyl)pyridine

5‐((1‐[¹¹C]‐methyl‐2‐(S)‐pyrrolidinyl)methoxy)‐2‐chloro‐3‐((E)‐2‐(2‐fluoropyridin‐4‐yl)‐vinyl)pyridine ([¹¹C]‐FPVC) was synthesized from [¹¹C]‐methyl iodide and the corresponding normethyl precursor. The average time of synthesis, purification, and formulation was 42 min with an average non‐decay‐corrected radiochemical yield of 19%. The average specific radioactivity was 359 GBq/µmol (9691 mCi/µmole) at end of synthesis (EOS). Copyright © 2006 John Wiley & Sons, Ltd.     

From β‐N‐tert‐butyloxycarbonyl N‐carboxyanhydrides to β‐aminoacid derivatives

Abstract: β‐N‐tert‐butyloxycarbonyl‐N‐carboxyanhydrides are very reactive β‐amino acid derivatives. They react cleanly and smoothly with different nucleophiles like aminoesters, enolates, N‐methyl‐d ‐glucamine, amidoximes to afford in good to excellent yields peptides, β‐amino ketocompounds, β‐aminosugars and functionalized disubstituted 1,2,4‐oxadiazoles.     

ATDC promotes the growth and invasion of hepatocellular carcinoma cells by modulating GSK‐3β/Wnt/β‐catenin signalling

Accumulating evidence has suggested that the ataxia telangiectasia group D complementing (ATDC) gene is an emerging cancer‐related gene in multiple human cancer types. However, little is known about the role of ATDC in hepatocellular carcinoma (HCC). In this study, we aimed to investigate the expression level, biological function and underlying mechanism of ATDC in HCC. The expression of ATDC in HCC cells was detected by quantitative real‐time polymerase chain reaction and western blot analysis. Cell growth was determined by cell counting kit‐8 assay and colony formation assay. Cell invasion was assessed by Transwell invasion assay. The activation status of Wnt/β‐catenin signalling was evaluated by the luciferase reporter assay. Functional experiments showed that the silencing of ATDC expression significantly suppressed the growth and invasion of HCC cells, whereas the overexpression of ATDC promoted the growth and invasion of HCC cells in vitro. Moreover, we showed that ATDC overexpression promoted the phosphorylation of glycogen synthase kinase (GSK)‐3β and resulted in the activation of Wnt/β‐catenin signalling. Notably, the inhibition of GSK‐3β activity significantly abrogated the tumour suppressive effect of ATDC silencing, while the silencing of β‐catenin partially reversed the oncogenic effect of ATDC overexpression. Taken together, these findings reveal an oncogenic role of ATDC in HCC and show that the suppression of ATDC impedes the growth and invasion of HCC cells associated with the inactivation of Wnt/β‐catenin signalling. Our study suggests that ATDC may serve as a potential therapeutic target for HCC.     

(Z)‐2‐(3‐Chlorobenzylidene)‐3,4‐dihydro‐N‐(2‐methoxyethyl)‐3‐oxo‐2H‐benzo[b][1,4]oxazine‐6‐carboxamide as GSK‐3β inhibitor: Identification by virtual screening and its validation in enzyme‐ and cell‐based assay

Glycogen synthase kinase 3β (GSK‐3β) is a widely investigated molecular target for numerous diseases including Alzheimer's disease, cancer, and diabetes mellitus. The present study was aimed to discover new scaffolds for GSK‐3β inhibition, through protein structure‐guided virtual screening approach. With the availability of large number of GSK‐3β crystal structures with varying degree of RMSD in protein backbone and RMSF in side chain geometry, herein appropriate crystal structures were selected based on the characteristic ROC curve and percentage enrichment of actives. The validated docking protocol was employed to screen a library of 50,000 small molecules using molecular docking and binding affinity calculations. Based on the GLIDE docking score, Prime MMGB/SA binding affinity, and interaction pattern analysis, the top 50 ligands were selected for GSK‐3β inhibition. (Z)‐2‐(3‐chlorobenzylidene)‐3,4‐dihydro‐N‐(2‐methoxyethyl)‐3‐oxo‐2H‐benzo[b][1,4]oxazine‐6‐carboxamide (F389‐0663, 7 ) was identified as a potent inhibitor of GSK‐3β with an IC₅₀ value of 1.6 μm . Further, GSK‐3β inhibition activity was then investigated in cell‐based assay. The treatment of neuroblastoma N2a cells with 12.5 μm of F389‐0663 resulted in the significant increase in GSK‐3β Ser9 levels, which is indicative of the GSK‐3β inhibitory activity of a compound. The molecular dynamic simulations were carried out to understand the interactions of F389‐0663 with GSK‐3β protein.     

The synthetic cathinone psychostimulant α‐PPP antagonizes serotonin 5‐HT2A receptors: In vitro and in vivo evidence

Synthetic cathinones (SCs) are β‐keto analogs of amphetamines. Like amphetamines, SCs target monoamine transporters; however, unusual neuropsychiatric symptoms have been associated with abuse of some SCs, suggesting SCs might possess additional pharmacological properties. We performed radioligand competition binding assays to assess the affinities of nine SCs at human 5‐HT_2A receptors (5‐HT_2AR) and muscarinic M₁ receptors (M₁R) transiently expressed in HEK293 cells. None of the SCs exhibited affinity at M₁R (minimal displacement of [~K_d] [³H]scopolamine up to 10 μM). However, two SCs, α‐pyrrolidinopropiophenone (α‐PPP) and 4‐methyl‐α‐PPP, had low μM K_i values at 5‐HT_2AR. In 5‐HT_2AR–phosphoinositide hydrolysis assays, α‐PPP and 4‐methyl‐α‐PPP displayed inverse agonist activity. We further assessed the 5‐HT_2AR functional activity of α‐PPP, and observed it competitively antagonized 5‐HT_2AR signaling stimulated by the 5‐HT₂R agonist (±)‐2,5‐dimethoxy‐4‐iodoamphetamine (DOI; K_b = 851 nM). To assess in vivo 5‐HT_2AR activity, we examined the effects of α‐PPP on the DOI‐elicited head‐twitch response (HTR) in mice. α‐PPP dose‐dependently blocked the HTR with maximal suppression at 10 mg/kg (P < 0.0001), which is a moderate dose used in studies investigating psychostimulant properties of α‐PPP. To corroborate a 5‐HT_2AR mechanism, we also tested 3,4‐methylenedioxy‐α‐PPP (MDPPP) and 3‐bromomethcathinone (3‐BMC), SCs that we observed had 5‐HT_2AR K_is > 10 μM. Neither MDPPP nor 3‐BMC, at 10 mg/kg doses, attenuated the DOI HTR. Our results suggest α‐PPP has antagonist interactions at 5‐HT_2AR in vitro that may translate at physiologically‐relevant doses in vivo. Considering 5‐HT_2AR antagonism has been shown to mitigate effects of psychostimulants, this property may contribute to α‐PPPs unpopularity compared to other monoamine transporter inhibitors.     

The peroxisome proliferator‐activated receptor‐γ agonist pioglitazone protects against cisplatin‐induced renal damage in mice

Peroxisome proliferator‐activated receptor‐γ (PPAR‐γ) agonists not only improve metabolic abnormalities of diabetes and consequent diabetic nephropathy, but they also protect against non‐diabetic kidney disease in experimental models. Here, we investigated the effect of PPAR‐γ agonist pioglitazone against acute renal injury on a cisplatin model in mice. Nephrotoxicity was induced by a single intraperitoneal (i.p.) injection of cisplatin (10 mg kg^–1). Pioglitazone was administered for six consecutive days in doses of 15 or 30 mg kg^–1 day^–1, per os (p.o.), starting 3 days before cisplatin injection. Cisplatin treatment to mice induced a marked renal failure, characterized by a significant increase in serum urea and creatinine levels and alterations in renal tissue architecture. Cisplatin exposure induced oxidative stress as indicated by decreased levels of non‐enzymatic antioxidant defenses [glutathione (GSH) and ascorbic acid levels] and components of the enzymatic antioxidant defenses [superoxide dismutase (SOD), catalase (CAT) glutathione peroxidase (GPx), glutathione reductase (GR) and and glutathione S‐transferase(GST) activities)] in renal tissue. Administration of pioglitazone markedly protected against the increase in urea and creatinine levels and histological alterations in kidney induced by cisplatin treatment. Pioglitazone administration ameliorated GSH and ascorbic acid levels decreased by cisplatin exposure in mice. Pioglitazone protected against the inhibition of CAT, SOD, GPx, GR and GST activities induced by cisplatin in the kidneys of mice. These results indicated that pioglitazone has a protective effect against cisplatin‐induced renal damage in mice. The protection is mediated by preventing the decline of antioxidant status. The results have implications in use of PPAR‐γ agonists in human application for protecting against drugs‐induced nephrotoxicity. Copyright © 2012 John Wiley & Sons, Ltd.     

Synthesis,docking, in vitro and in vivo antidiabetic activity of pyrazole‐based 2,4‐thiazolidinedione derivatives as PPAR‐γ modulators

The design, synthesis, structure–activity relationship, and biological activity of 2,4‐thiazolidinedione derivatives as peroxisome proliferator‐activated receptor‐γ (PPAR‐γ) modulators for antidiabetic activity are reported. Fifteen 2,4‐thiazolidinedione derivatives clubbed with pyrazole moiety were docked into the ligand binding domain of PPAR‐γ by the Glide XP module of Schrodinger. Eight derivatives ( 5a , 5b , 5d , 5f , 5i , 5l , 5n , 5o ) having Glide XP scores > ?8 as compared to the standard drug, rosiglitazone (Glide XP score = ?9.165), showed almost similar interaction with the amino acids such as HIS 449, TYR 473, TYR 327, HIS 323, and SER 289 in the molecular docking studies. These eight derivatives were further screened for PPAR‐γ transactivation and in vivo blood glucose lowering activity in the streptozotocin‐induced diabetic rat model. Compounds 5o , 5n , 5a , 5i , and 5b showed 52.06, 51.30, 48.65, 43.13, and 40.36% PPAR‐γ transactivation as compared to the reference drugs rosiglitazone and pioglitazone with 85.30 and 65.22% transactivation, respectively. The data analysis showed significant blood glucose lowering effects (hypoglycemia) of compounds 5o , 5n , and 5a (140.1 ± 4.36, 141.4 ± 6.15, and 150.7 ± 4.15, respectively), along with reference drugs pioglitazone (135.2 ± 4.91) and rosiglitazone (141.1 ± 5.88) as compared to the diabetic control. Furthermore, the most potent compound 5o also elevated the PPAR‐γ gene expression by 2.35‐fold as compared to rosiglitazone (1.27‐fold) and pioglitazone (1.6‐fold). It also significantly lowered the AST, ALT, and ALP levels and caused no damage to the liver.

     

RNAi Silencing of IL‐1β and TNF‐α in the Treatment of Post‐traumatic Arthritis in Rabbits

Post‐traumatic arthritis is a secondary complication to severe joint trauma. With the disease progression, it may eventually lead to osteoarthritis in patients whose age is considerably younger than patients with traditional bone arthritis. The main objective of this study was to explore the feasibility of using lentiviral‐mediated RNA interference silencing of IL‐1β and TNF‐α to treat post‐traumatic arthritis in rabbits. About 48 New Zealand rabbits underwent bilateral knee joint surgery to stimulate traumatic arthritis. They were then randomly divided into four groups of 12 rabbits each. The histopathology of the cartilage was observed, and the changes were assessed by Mankin scoring. ELISA was used to detect the expression of IL‐1β and TNF‐α in the synovial fluid. (i) Compared with the control group, the transfection and co‐transfected groups displayed reduced cartilage damage and speed of degeneration. The co‐transfected group showed the greatest alleviation of symptoms. The Mankin score was statistically different (p < 0.01). (ii) Compared with the control group, the expression of IL‐1β or TNF‐α was reduced in the respective transfection groups (p < 0.01 in both groups) and IL‐1β and TNF‐α were reduced in the co‐transfected group (p < 0.01). The co‐transfected group showed the lowest expression of the three experimental groups of both IL‐1β and TNF‐α (p < 0.01). Lentivirus‐mediated RNA interference can knock down the expression of IL‐1β and TNF‐α in joint fluids and, in a synergistic effect when two siRNAs are co‐transfected, ease cartilage degeneration.