Mesenchymal stem cell-derived exosomal miR-27b-3p alleviates liver fibrosis by way of downregulating YAP/LOXL2 pathway | Journal of Nanobiotechnology

Cell tradition

The human umbilical wire was gained from knowledgeable, wholesome parturients, and MSC was remoted from the human umbilical wire and recognized as described beforehand [22]. All medical procedures adopted the protocols accredited by the ethics committee of Jiangsu College, and the accredited pointers carried out the strategies. All members have written consent for the current examine. MSC was cultured in L-DMEM (Gibco, Thermo Fisher Scientific) containing 10% fetal bovine serum (FBS) (Bovogen, Australia). Human immortalized L02 cells (Chinese language Academy of Sciences) have been maintained in RPMI 1640 containing 10% FBS (Bovogen, Australia). HEK293T cells (ATCC) have been maintained in L-DMEM (Gibco, Thermo Fisher Scientific) containing 10% fetal bovine serum (FBS) (Bovogen, Australia). Human immortalized HSC cell line LX-2 (Chinese language Academy of Sciences) was maintained in H-DMEM (Gibco) containing 10% FBS (Bovogen, Australia). All cells have been cultured at 37 °C with 5% CO2 and examined for mycoplasma contamination.

Isolation and characterization of MSC-ex

MSC-ex was remoted and purified as our beforehand established methodology [21]. MSC was cultured in an FBS-free medium, by which bovine exosomes and protein aggregates have been eliminated by ultra-centrifugation at 100,000×g for 16 h at 4 °C. 500 mL situation medium from MSC at passages 3 to six was collected, and centrifuged at 2000×g for 20 min to take away cell particles. Then, Supernatants have been concentrated utilizing a 100 KDa molecular weight cut-off (MWCO) ultrafiltration filter per the producer’s directions (Millipore, USA). After filtration with 0.22 μM filter membrane, the exosomes-enriched fraction was transferred to a 15 mL sterile centrifuge tube. MSC-ex was precipitated from the concentrates utilizing ExoQuick-TC extracellular vesicle (EV) isolation Package following the protocol (System Biosciences, USA). The protein focus of the extracted exosomes was quantified by a BCA protein assay package (Pierce, ThermoFisher). The morphology of MSC-ex was noticed by transmission electron microscopy (FEI Tecnai 12, Philips). The quantity and dimension distribution of MSC-ex was measured by NanoSight monitoring evaluation (NTA) with NTA 3.1 Software program (NanoSight, Malvern, UK).

CCl4-induced mouse mannequin of liver fibrosis and MSC-ex injection

All experiments involving animals have been carried out based on the moral insurance policies and procedures accredited by the Jiangsu College ethics committee (Approval no. UJS-IACUC-AP-2020033127). BALB/c feminine mice, 4–5 weeks previous, have been handled with carbon tetrachloride (CCl4) (10%) for six weeks to induce liver fibrosis as described. To investigate the impact of MSC-ex on LOXL2 expression and liver fibrosis, mice have been randomized into 4 teams: PBS group, mice injected with 1 mL PBS (n = 6); 3-aminopropionitrile fumarate salt (BAPN) group, mice handled with BAPN (125 mg/kg, Sigma-Aldrich, n = 6) as soon as per day; and MSC-ex 12.5 mg/kg physique weight (n = 6), 25 mg/kg physique weight (n = 6) teams, mice handled with MSC-ex twice every week. PBS, BAPN, and MSC-ex have been administered by tail vein. At 4 weeks submit MSC-ex injection, mice have been sacrificed to gather blood and liver samples for additional evaluation.

MSC-ex labeling and monitoring in mice and LX-2 Cells

MSC-ex was incubated with DiR (DiIC 18(7); 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindotricarbocyanine iodide) (UElandy Biology, China) or PKH67 (Sigma-Aldrich, USA) for 30 min at 37 °C based on the producer’s directions. After washing with PBS, DiR or PKH67 labeled MSC-ex have been concentrated with a 100 KDa molecular weight cut-off (MWCO) ultrafiltration filter at 1000×g for 30 min to take away the non-binding dye. For in vivo monitoring of MSC-ex in mice, DiR labeled MSC-ex have been injected intravenously and analyzed utilizing a Maestro In Vivo Imaging System (CRI, MA, USA). In vivo, spectral imaging from 690–850 nm was carried out utilizing an publicity time of 150 ms per picture body. For the distribution of MSC-ex in LX-2, PKH67 labeled MSC-ex (PKH67-ex) was incubated with LX-2 cells at 37 °C for twenty-four h and noticed with confocal microscopy.

Western blot

Entire-cell or MSC-ex lysates have been ready in RIPA lysis buffer (Beyotime, Shanghai, China). Protein focus was decided utilizing the BCA assay package (Vazyme Biotech, Nanjing, China). Equal quantities of lysates have been loaded and separated on a ten% or 12% SDS-PAGE gel. Normal Western blot used main antibodies and a peroxidase-linked, species-specific, anti-mouse, anti-rat, or anti-rabbit IgG (CWBIO, China). The next main antibodies have been used: CD9 (1:500, Bioworld, USA, BS3022), CD63 (1:1000, Abcam, UK, ab271286), Calnexin (1:2000, Sigma-Aldrich, USA, BS1438), TSG101 (1:1000; Abcam, UK, BS91381), α-SMA (1:1000; Bioworld, USA, BM0002), LOXL2 (1:2000; Bioworld, USA, MB63843), YAP (1:1000; Bioworld, USA, BS2000), β-actin (1:2000; ABclonal, UK, Rabbit, AC006). and GAPDH (1:2000; Abclonal, China, AC001). Proteins have been detected with an ECL detection system (Amersham Pharmacia Biotech, Little Chalfont, UK). Western blot outcomes have been quantitated utilizing ImageJ software program; protein expression was normalized to GAPDH.

Quantitative reverse transcription PCR

The full RNA of LX-2 cells and mouse livers have been extracted with Trizol based on the producer’s directions (Invitrogen). 1 µg of complete RNA was used for the reverse transcription of RNA into cDNA in a response utilizing the SuperScriptTM II RT package based on the producer’s directions (Invitrogen). SYBR-Inexperienced I-based Actual-Time PCR package (Vazyme Biotech Co., Ltd, China) was used, and relative gene expression quantitation was decided utilizing the two−ΔΔCT methodology and normalized to the β-actin gene. The PCR primers are listed in Desk 1 (Shanghai Bio-Engineering, China). The fluorescence alerts have been detected by CFX96 Contact™ Actual-Time PCR Detection System (Bio-Rad, USA). MiScript primer assays have been used for the semiquantitative dedication of human miR-27b-3p (Qiagen GmbH, Germany). Relative gene expression normalized to U6 was calculated utilizing the two−ΔΔCt methodology. There have been three or six replicates per group.

Desk 1 Primers for real-time quantitative PCR

Serum assay

Serum LOXL2 ranges in fibrotic mice handled with MSC-ex or BAPN have been decided utilizing an ELISA (Enzyme-linked Immunosorbent Assay) package (XinYu Biotech, Shanghai, China) based on the producer’s directions. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and UREA have been measured with an automatic biochemical analyzer.

Immunohistochemistry and immunofluorescence of liver tissues

LOXL2, YAP, and α-SMA protein expressions have been analyzed utilizing MSC-ex or BAPN-treated mouse tissue samples. Mouse tissue sections (4 µm thick) of formalin-fixed, paraffin-embedded liver specimens have been deparaffinized in xylene and rehydrated in graded alcohol. Normal immunohistochemical procedures have been carried out on liver tissue sections utilizing anti-LOXL2 (1:50; Santa Cruz Biotechnology, USA), anti-YAP (1:50; Bioworld, USA), or anti-α-SMA antibody (1:50; Bioworld, USA). Alerts have been visualized utilizing 3, 3′-Diamino-benzidine tetrahydrochloride (Boster Biology, Wuhan, China). A brown membrane, cytoplasmic, and nuclear staining indicated a constructive response based on completely different markers. The staining results of LOXL2, YAP, and α-SMA expression was decided by the share of constructive cells by two investigators blinded to the information. Immunofluorescence staining was carried out utilizing anti-CD9 (1:100, Bioworld, USA), anti-LOXL2 (1:50), anti-YAP (1:50), or anti-α-SMA antibody (1:50). Unfavourable controls with isotype IgG have been run in parallel. Photos have been acquired utilizing a laser scanning confocal microscope (Nikon, Tokyo, Japan).

Hematoxylin and eosin (HE) staining

Formalin-fixed paraffin-embedded cardiac, liver, spleen, lung, and kidney tissues sections have been stained with Masson Trichrome (MT) (Gefan, China) and Sirius Crimson (Chondrex, USA) based on the instruction of the producer. To investigate hepatic collagen distribution, 10 fibrotic septa randomly chosen from the appropriate and left liver lobes of 6 particular person mice/teams have been assessed. Collagen extent was expressed as a share of stained space in every liver part.

TGFβ induced LX-2 activation and MSC-ex therapy

LX-2 was cultured in a 6-well plate till it reached roughly 50–60% confluence. Then cells have been randomized into 4 teams: PBS, LX-2 handled with PBS, TGFβ: LX-2 handled with 10 ng/mL TGFβ, TGFβ/MSC-ex, LX-2 handled with 10 ng/mL TGFβ and 100 or 200 μg/mL MSC-ex, TGFβ/BAPN: LX-2 handled with 10 ng/mL TGFβ and 1.0 mg/mL BAPN. These cells have been handled for 48 h for additional investigation.

Immunofluorescence of LX-2

LX-2 cells have been fastened in 4% paraformaldehyde for 10 min and permeabilized with 0.1% Triton X-100 for 10 min at room temperature. For analyzing LOXL2, YAP, and α-SMA protein ranges, LX-2 cells have been blocked with 5% BSA and incubated with anti-LOXL2, anti-YAP, or anti-α-SMA main antibody at 4 °C in a single day; after incubation and washing, fluorescent-labeled secondary antibody was added with the mandatory incubation and washing. Then the slides have been counterstained with 4′,6-diamidino-2-phenylindole (DAPI) for nuclear staining and examined beneath a laser scanning confocal microscope (Nikon, Tokyo, Japan).

Adenoviral overexpression and knockdown of YAP

Adenoviruses expressing full-length human YAP (Advert-YAP), GFP alone (Advert-GFP), YAP shRNA (sh-YAP), and management shRNA (sh-Ctr) have been constructed. Full-length human YAP cDNA was inserted into pAV(Exp)-CMV > YAP/HA-IRES-Egfp adenoviral vectors to generate Advert-YAP expression vectors. The adenoviral YAP shRNA vector was packaged by the vector ADV1(U6/CMV-GFP) with YAP shRNA oligonucleotides. The shRNA oligonucleotide sequences are listed in Desk 2. Recombinant adenovirus was produced by co-transfecting 293A cells, as described beforehand. YAP overexpression and knockdown effectivity have been evaluated utilizing quantitative Reverse Transcription PCR and western blot. To arrange YAP-modified 293T and LX-2 cells, Advert-YAP and sh-YAP transfected cells have been collected.

Desk 2 shRNA oligonucleotides

Promoter exercise evaluation

The LOXL2 promoter constructs pcDNA3.1-LOXL2-907 (pLOXL2-907), pcDNA3.1-LOXL2-826 (pLOXL2-826) and pcDNA3.1-LOXL2-328 (pLOXL2-328) have been Chemically synthesized (GENERAL BIOL, Anhui, China). For the LOXL2 reporter assay, HEK293T and LX-2 cells have been seeded in 24-well plates. The LOXL2 promoter constructs and Renilla luciferase reporter have been cotransfected with plasmid DNA of pcDNA3.1-vector (p3.1), pcDNA3.1-YAP (pYAP), and in some experiments, management shRNA (sh-Ctr) or YAP shRNA (sh-YAP). Lipofectamine 2000 reagent (Life Applied sciences) was used based on the producer’s directions. Each firefly and Renilla luciferase exercise have been measured utilizing a dual-luciferase assay system (Promega, Madison, USA) 48 h after transfection. The LOXL2 promoter exercise was normalized with the Renilla luciferase exercise. Three organic repeats have been used for every pattern within the twin luciferase reporter.

Chromatin immunoprecipitation quantitative real-time PCR (ChIP-qPCR)

Chromatin immunoprecipitation (ChIP) assay adopted the producer’s directions (Millipore, Billerica, MA). Briefly, formaldehyde was used to cross-link proteins with DNA, and a pair of × 107 293T or LX-2 cells have been lysed in sodium dodecyl sulfate lysis buffer. The cell lysate was sonicated to shear the DNA to 400- to 600-bp lengths. Chromatin samples have been then precleared with a salmon sperm DNA/protein A agarose 50% slurry for 30 min at 4 °C and immunoprecipitated in a single day with anti-IgG or anti-YAP (Bioworld, USA, BS9920M). The purified DNA fragments have been subjected to quantitative PCR utilizing primers listed in Desk 1. 4 organic replications have been included in every therapy.

Luciferase reporter assays

YAP was predicted as a goal of miR-27b-3p by TargetScan ( The 3ʹ‑untranslated area (UTR) of the human YAP gene containing both wild-type (WT) or mutant-type (MT) binding websites of miR-27b-3p have been synthesized and inserted within the pGL3 vector downstream of the firefly luciferase gene to kind pGL3-YAP, named as YAP-WT and YAP-Mut. LX-2 cells (2.5 × 104/effectively) have been seeded in 24-well plates and have been co-transfected with miR-27b-3p mimics or destructive management (NC) miRNA mimics and management reporter plasmids pGL3, YAP-WT or YAP-Mut utilizing Lipofectamine 2000. The Twin-Luciferase Reporter assay system (Promega, USA) was utilized to look at the actions of Renilla and firefly luciferase based mostly on the producer’s protocols at 24 h post-transfection. Firefly luciferase exercise was normalized to Renilla luciferase exercise.

Crystal droplet digital PCR™ assays

Droplet digital PCR was carried out utilizing the naica® system (Stilla Applied sciences, France). 125 ng RNA was remoted from MSC-ex (104 particles). 500 ng RNA in 20 μL was used per response to generate cDNA by reverse transcription. The response combination consisted of two μL QX200 ddPCR EvaGreen (Bio-Rad), 1 μL Laxa Fluor 647 dye (Thermo Fisher), 3.75 μL ddPCR™ supermix for probes (Bio-Rad), 1 μL primer, and 5 μL DNA template. Lastly, RNase-free H2O was added to make a complete response quantity of 25 μL. The 2-step methodology is used for ddPCR, and the biking process consists of a pre-denaturation step at 95 °C for five min, adopted by 45 cycles of denaturation at 95 °C for 10 s, annealing at 62 °C for 45 s, and 72 °C for 30 s. After the PCR cycle, the sapphire chip was transferred to a Naica Prism 3 fluorescence reader for imaging. Crystal Miner software program (Stilla Applied sciences) was used for information evaluation.

Fluorescence in situ hybridization (FISH)

Cy3-labeled miR-27b-3p probe sequence was bought from GenePharma, China. 3 × 105 cells have been cultured in 24-well glass slide plates. 4% paraformaldehyde was used to repair the cells. 15 min of TRITON X-100 therapy was adopted by incubation with blocking resolution for 30 min (37 °C). Cy3-labeled miR-27b-3p fluorescent probe resolution was incubated with cells in an in situ hybridizer for 14 h (37 °C). Tween 20 was used to scrub the cells. For liver tissue, 7 mm frozen liver tissue sections have been digested with proteinase Ok and incubated in a blocking buffer for 30 min (37 °C). Put together the cy3-labeled miR-27b-3p fluorescent probe working resolution at a quantity ratio of 1:1. Incubate with liver tissue slices for 14 h (37 °C) in an in situ hybridization instrument. Wash sections with deionized formamide at 43 °C to denature unhybridized probes. Sections have been washed thrice with sodium citrate buffer (60 °C). FISH pictures have been then captured by confocal microscopy.

miR-27b-3p mimics or inhibitors transfection

Human miR-27b-3p mimics, destructive management mimics, and miR-27b-3p inhibitors, destructive management inhibitors have been bought from GenePharma, China. In accordance with the instruction of the producer, miR-27b-3p mimics (25 nM, 50 nM) and miR-27b-3p inhibitors (50 nM, 100 nM) have been transiently transfected into LX-2 cells utilizing Lipofectamine 2000 in Opti-MEM™ medium (Invitrogen, USA) at 70–80% confluency in 6-well tradition plates. At 4–6 h post-transfection, the tradition medium was changed with MEM with 10% FBS for an additional 48 h. The transfected cells have been collected for additional investigation.

miR-27b-3p knockdown of MSC-ex

Unfavourable management inhibitors, miR-27b-3p inhibitors (50 nM, 100 nM), have been transiently transfected into MSC utilizing Lipofectamine 2000 in Opti-MEM™ medium (Invitrogen, USA) at 70–80% confluency in 6-well tradition plates. At 4–6 h post-transfection, the tradition medium was changed with an FBS-free medium for an additional 48 h. Then complete RNA of inhibitors transfected MSC was collected for miR-27b-3p quantification. miR-27b-3p inhibitors transfected MSC-ex (miR-27bin-ex), or destructive management inhibitors transfected MSC-ex (NCin-ex) have been remoted, purified, and washed as our beforehand established methodology. After focus and construction identification, miR-27bin-ex or NCin-ex have been saved at − 70 °C for additional use. Then LX-2 cells have been handled with NCin-ex (200 μg/mL) or miR-27bin-ex (2000 μg/mL) for 48 h and picked up for additional investigation.

miR-27b-3p mimics the loading of exosomes

miR-27b-3p mimics have been passively loaded into MSC-ex by the sonication methodology. MSC-ex was combined with 50 nM miR-27b-3p mimics or destructive management mimics and sonicated at 500 v, 2 kHz, 10% energy, 6 cycles by 4 s pulse/2 s pause, cooled down on the ice for two min, after which sonicated once more utilizing Qsonica Sonicator Q700 (Misonix, USA). Then miR-27b-3p overexpressed MSC-ex (miR-27boe-ex) or destructive management mimics overexpressed MSC-ex (NCoe-ex) have been washed with PBS 3 instances to take away residual miRNA. After focus and construction identification, miR-27boe-ex or NCoe-ex have been saved at − 70 °C for additional use. Then LX-2 cells have been handled with NCoe-ex (50 μg/mL) or miR-27boe-ex (50 μg/mL) for 48 h and picked up for additional investigation.

Statistical evaluation

Statistical analyses have been carried out utilizing GraphPad Prism model 8.3.0 (San Diego, CA, USA). All the information is introduced as imply ± SD. The Scholar’s t-test was used for comparisons between the 2 teams. One-way evaluation of variance (ANOVA) adopted by Dunnett was used for research involving greater than two teams. A two-sided p < .05 was thought-about statistically important.

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