Tris[2-(acryloyloxy)ethyl]isocyanurate Cross-Linked Low-Molecular-Weight Polyethylenimine as Gene Delivery Carriers in Cell Culture and Dystrophic <i>mdx</i> Mice

Hyperbranched poly­(ester amine)­s (PEAs) were successfully synthesized by Michael addition reaction between tris­[2-(acryloyloxy)­ethyl]­isocyanurate (TAEI) and low-molecular-weight polyethylenimine (LPEI, <i>M</i>_w 0.8k, 1.2k, and 2.0k) and evaluated <i>in vitro</i> and <i>in vivo</i> as gene carriers. PEAs effectively condensed plasmid DNA with particle sizes below 200 nm and surface charges between 11.5 and 33.5 mV under tested doses [at the ratios 2–10:1 of polymer/pDNA­(w/w)]. The PEAs showed significantly lower cytotoxicities when compared with PEI 25k in two different cell lines. The PEAs (C series) composed of PEI 2k showed higher transgene expression compared to PEAs of PEI 0.8k (A series) or 1.2k (B series). Highest gene transfection efficiency in CHO, C2C12 myoblast, and human skeletal muscle (HSK) cell lines was obtained with TAEI/PEI-2K (C12) at a ratio of 1:2. Both C12, C14­(TAEI/PEI-2K at a ratio of 1:4) demonstrated 5–8-fold higher gene expression as compared with PEI 25k in <i>mdx</i> mice <i>in vivo</i> through intramuscular administration. No obvious muscle damage was observed with these new polymers. Higher transfection efficiency and lower toxicity indicate the potential of the biodegradable PEAs as safe and efficient transgene delivery vectors

AOs target human dystrophin exon 50 in C2C12hE50 GFP reporter myoblasts 48 hours after treatment.

<p>(A). RT-PCR for the detection of GFP/hE50 mRNA in the C2C12hE50 cells. Left lane is the 100bp size marker. Con, Control sample without PMO treatment; 12, 5, 23 are the hE50AOPMOs. The bands marked with +E50 representing normal dystrophin mRNA containing E50; The bands marked with −E50, representing dystrophin mRNA with hE50 skipped. The band representing hE50 skipping was most strongly detected in the cells treated with hE50AO23PMO. (B) and (C) cells treated with the hE50AOPS and hE50AOPMO respectively. (D). FACS analysis for the GFP positive cells treated with the 3 hE50AOPMOs and the control (without AO treatment).</p

Dose dependent human dystrophin exon 50 skipping with the hE50AO23PMO in normal human myoblast and skin fibroblasts of a DMD patient with exon 51 deletion.

<p>The signal intensity of the strongest bands representing exon 50 skipping was 71% and 65% in the normal human myoblas (A) and skin fibroblasts (B) respectively (measured with NIH ImagJ). (C). C2C12hE50 reporter myoblasts. (D). FACS analysis of the C2C12hE50 reporter cells treated with the hE50AO23PMO with the concentrations specified.</p

RT-PCR and Nested-PCR for the detection of hE50 skipping in the normal human myoblasts and the DMD-derived skin fibroblasts.

<p>(A). Samples from the normal human myoblasts cells treated with 2OMePS AOs; (B). Samples from the normal human myoblasts cells treated with PMOs. +hE50 representing normal dystrophin mRNA containing hE50; −hE50, representing dystrophin mRNA with hE50 skipped. Left lane is the 100 bp size marker; (C). A sequence showing skipping of the hE50 from the PCR product detected as –hE50 in the hE50AO24PMO treated normal human myoblasts cells in (B). (D). The bands marked with +hE50+hE51 representing normal human dystrophin mRNA (NhM) from normal human myoblasts; the bands marked with +hE50−hE51 representing mRNA from the skin fibroblasts of a DMD patient with exon 51 deletion; the bands marked with −hE50 and –hE51 representing mRNA from the skin fibroblasts with exon 50 skipped (both exons are absent). Control, without AO treatment.</p

List of AO compounds, the sequence and size of AOs and the summary of their exon skipping effect.

<p>PS, 2OMePS AO. − and + within the Target column indicate the intron and exon sequences respectively; the numbers represent the first and last nucleotides of the oligonucleotide sequences. Percentage of GFP positive cells with 2OMePS AOs is the average from the flow cytometry analysis. Results from PMO treatment are presented as mean values ± SE with statistical analysis (ANOVA) since a completed set of exon skipping efficiency analysis including the in vivo test was conducted with those PMOs.</p>*<p><i>P</i><0.01 was obtained by comparison of the groups with the hE50AO28PMO groups (n = 3). GFP, GFP reporter C2C12hE50 cells; hM, normal human myoblasts. DMD, DMD patient-derived skin fibroblasts with exon 51 deletion. Scores: -, no positive signal above background is observed for either GFP expression or signals representing mRNA with exon 50 skipping when compared to the samples of negative controls. Cells were treated with 1 µM AOs. N/D. Muscles of hDMD/<i>mdx</i> mice were treated with 10 µg Vivi-PMO.</p

Effect of Vivo-PMO for human dystrophin exon 50 skipping systemically in the hDMD/<i>mdx</i> mice.

<p>TA, tibialis anterior; Quad, quadriceps; Gastro, gastronemium; Abdom, abdominal; Diaph, diaphragm. The signal intensity of the bands representing human dystrophin exon 50 skipping was 70±13% and 5±1%, 20±5% and 0% in body-wide skeletal muscles and cardiac muscles treated with Vivo-hE50AO23PMO and Vivo-hE50AO5PMO respectively (measured with NIH ImagJ) (A). Results are presented as mean values ± SE with statistical analysis (t-test). *<i>P</i><0.01 was obtained by comparison of the Vivo-hE50AO23PMO group with the hE50AO5PMO group. (n = 5) (B). Immunohistochemical staining shows similar intensity for dystrophin after the Vivo-PMO treatments in all muscles tested. (C). Serum enzyme tests show a slight increase in the levels of creatine kinase in the mice treated with Vivo-PMOs.</p

Effect of Vivo-PMO for dystrophin exon skipping in tibialis anterior (TA) muscles of normal C57 mice and in the hDMD/<i>mdx</i> mice.

<p>(A). The signal intensity of the bands representing mouse dystrophin exon 23 skipping with Vivo-PMOE23 from normal C57 mice was 70±7%. (B). Signal intensity of the bands representing human dystrophin exon 50 skipping after Vivo-hE50AO23PMO treatment from the hDMD/<i>mdx</i> mice was 65±7%, significantly higher when compared with 25±6%, 34±4% detected after Vivo-hE50AO12PMO and Vivo-hE50AO5PMO treatment. Results from 2 TA muscles for each Vivo-PMO are presented. Signal intensity was measured with NIH Image J. Results are presented as mean values ± SE with statistical analysis (t-test). *<i>P</i><0.01 was obtained by comparison of the group(s) with PMOE23 and hE50AO12PMO group in (A) and (B) respectively (n = 5). (C). H&E staining of the TA muscles treated with Vivo-PMOs. No change in muscle histology was detected. Control, saline injected TA muscle.</p

MSC-EV therapy improves ALI in a rat model of the disease.

(A) Schematic of the LPS-induced rat model of ALI depicting LPS intratracheal installation and MSC-EV intravascular administration. (B) IL-6, TNFα and (C) IL-10 were measured in bronchoalveolar lavage fluid (BAL). (D) Serum cytokine levels normalized to naïve control. (E) histology lung scans (left panel) with representative magnification (right panel). Histology scans were used to calculate (F) Lung injury score and (G) percent alveolar space. Scale bar denotes 2 mm (left panel) and 100 μm (right panel). Plethysmography (H) respiratory rate and (I) minute volume. (J) lung weight and lung index. (K) infiltrating cells from the BAL. (L) BAL cytokines normalized to naïve control. (M) MSC-EV percent maximal response in the BAL. (N) serum cytokines normalized to naïve control. (O) MSC-EV percent maximal response in serum. Error bars are SEM of the mean. * p<0.05 vs LPS (cytokine, lung function); & p<0.1 vs LPS (lung function) $ p<0.05 vs LPS (lung weight); + vs LPS (lung index) # P<0.05 vs LPS (Macrophage); ^ P<0.05 vs LPS (Lymphocyte); % P<0.05 vs LPS (Neutrophil).</p

MSC-EVs improve cell health after exposure to cytokine mix.

Calu-3 cells were incubated with SARS-CoV-2 receptor binding domain (RBD) alone or in combination with tri-cytokine mix (CM). ACE2 mRNA (A) CD14 surface protein (B) and 4-HNE protein adducts (C) were evaluated. LDH (D) and cell permeability (E) were evaluated in calu-3 cells incubated with tri-cytokine mix (CM) alone. Activities of caspase-1, caspase-3/7, caspase-8 were evaluated in CM-treated calu-3 lysates over time (F-H). Error bars are SEM of the mean. *p ≤0.05 vs unstressed; #p ≤0.05 vs CM. (TIF)</p

MSC-EVs decrease epithelial cell inflammation and improve cell health.

Cytokine secretion was measured in (A) THP1 cell culture media after LPS administration and (B) calu-3 cell culture media after tri-cytokine addition (CM). Calu-3 cell viability was evaluated after a 24-hour CM exposure (C). Caspase-1 (D), caspase-3/7 (E), and caspase-8 (F) activities were evaluated in calu-3 cell lysates over time. LDH release into calu-3 culture media (G), cell permeability (H), and growth factor secretion into the media (I). Transepithelial/endothelial electrical resistance (TEER) was evaluated on primary human alveolar type 2 (AT2) after 24-hour (J) or 72-hour CM exposure (K). AT2 in co-culture with microvascular endothelial cells (MVEC) after 24-hour (L) or 72-hour CM exposure (M). Error bars are SEM of the mean. *p ≤0.05 vs PBS control; #p ≤0.05 vs CM.</p