siRNA Targeting Research Articles

CXCL6 promotes the progression of NAFLD through regulation of PPARα

An increasing number of studies have shown that Nonalcoholic fatty liver disease (NAFLD) is strongly associated with obesity, insulin resistance, dyslipidemia, hypertension and metabolic syndrome, but its specific pathogenesis remains unclear. By analyzing GEO database, we found CXCL6 was upregulated in liver tissues of patients with NAFLD. We also confirmed with qPCR that CXCL6 is highly expressed in serum of patients with NAFLD. To identify the underlying impact of CXCL6 on NAFLD, we established animal and cell models of NAFLD. Similarly, we confirmed by qPCR and Western blot that CXCL6 was upregulated in the NAFLD model in vitro and vivo. After transfecting NAFLD cells with siRNA targeting CXCL6 (si-CXCL6), a series of functional experiments were carried out, and these data indicated that the inhibition of CXCL6 reduced intracellular lipid deposition, decreased AST, ALT and TG level, facilitate cell proliferation and suppress their apoptosis. Furthermore, western blot and qPCR analyses displayed that the suppression of CXCL6 could raise the PPARα expression, but PPAR α inhibitor, GW6471 could partially counteract this effect. What’s more, Oil Red O staining, biochemical analyzer and TG detection kit revealed that GW6471 could reverse the inhibitory effect of si-CXCL6 on NAFLD. In summary, we provide convincing evidence that CXCL6 is markedly elevated in NAFLD, and the CXCL6/PPARα regulatory network mediates disease progression of NAFLD.

Septic macrophages induce T cells immunosuppression in a cell-cell contact manner with the involvement of CR3

BackgroundIn addition to excessive inflammation, immunosuppression has been recognized as a contributing factor to poor prognosis of sepsis. Although it has been reported that T cells can become functionally impaired during sepsis, the underlying mechanisms responsible for this phenomenon remain unclear. This study aims to elucidate the mechanisms by which macrophages induce immunosuppression in T cells. MethodsIn an in vivo setting, C57BL-6J mice were subjected to cecal ligation and puncture (CLP) with or without depletion of macrophages, and the functions of T cells were assessed. In vitro experiments involved direct co-culture or separate culture of T cells and septic macrophages using a transwell system, followed by analysis of T cell immunity. Additionally, a siRNA targeting CD18 on macrophages was utilized to investigate the role of complement receptor 3 (CR3). ResultsBoth macrophages and T cells exhibited immunosuppression during sepsis. In the in vivo experiments, the absence of macrophages partially alleviated T cell immunosuppression, as evidenced by restored vitality, increased production of TNF-α and IFN-γ, elevated CD8+ T cell levels, and decreased CD25+ T cell levels. In the in vitro experiments, direct co-culture of T cells with septic macrophages resulted in diminished T cell immunity, which was improved when T cells and macrophages were separated by a chamber wall. The expression of CR3 (CD11b/CD18) was upregulated on septic macrophages, and silencing of CD18 led to decreased TNF-α production by T cells, reduced CD4+ T cell numbers, and increased CD25+ T cell numbers. ConclusionIn sepsis, macrophages induce immunosuppression in T cells through direct cell-cell contact, with the involvement of CR3.

Host-Cell-Dependent Roles of E-Cadherin in Serratia Invasion.

Bacteria use cell surface proteins to mediate host-pathogen interactions. Proteins responsible for cell adhesion, including E-cadherin, serve as receptors for entry into the host cell. We have previously shown that an increase in eukaryotic cell sensitivity to Serratia grimesii correlates with an increase in E-cadherin expression. On the other hand, Serratia proteamaculans invasion involves the EGFR, which can interact with E-cadherin on the surface of host cells. Therefore, we investigated the role of E-cadherin in Serratia invasion into M-HeLa and Caco-2 cells. Bacterial infection increased E-cadherin expression in both cell lines. Moreover, E-cadherin was detected in the Caco-2 cells in a full-length form and in the M-HeLa cells in only a truncated form in response to incubation with bacteria. Transfection with siRNA targeting E-cadherin inhibited S. proteamaculans invasion only into the Caco-2 cells. Thus, only full-length E-cadherin is involved in S. proteamaculans invasion. On the other hand, transfection with siRNA targeting E-cadherin inhibited S. grimesii invasion into both cell lines. Thus, not only may full-length E-cadherin but also truncated E-cadherin be involved in S. grimesii invasion. Truncated E-cadherin can be formed as a result of cleavage by bacterial proteases or the Ca2+-activated cellular protease ADAM10. The rate of Ca2+ accumulation in the host cells depends on the number of bacteria per cell upon infection. During incubation, Ca2+ accumulates only when more than 500 S. grimesii bacteria are infected per eukaryotic cell, and only under these conditions does the ADAM10 inhibitor reduce the sensitivity of the cells to bacteria. An EGFR inhibitor has the same quantitative effect on S. grimesii invasion. Apparently, as a result of infection with S. grimesii, Ca2+ accumulates in the host cells and may activate the ADAM10 sheddase, which can promote invasion by cleaving E-cadherin and, as a result, triggering EGFR signaling. Thus, the invasion of S. proteamaculans can only be promoted by full-length E-cadherin, and S. grimesii invasion can be promoted by both full-length and truncated E-cadherin.

#296 : Identification and Validation of Two Novel Therapeutic Targets for Endometriosis with Artificial Intelligence (AI)

Background and Aims: It is urgent need to develop new-effective and well-tolerable medical treatment for endometriosis, but normal drug development is tedious, costly and time-consuming. Artificial intelligence (AI) is a powerful tool to drive discovery of novel druggable targets. Here we aim to use AI to identify novel therapeutic targets for endometriosis treatment. Method: Targets associated with endometriosis were prioritized by PandaOmics (a well-established AI-driven target identification platform). Expression levels of druggable targets were tested in human endometriotic lesions. Functional characterizations of the targets were performed by in-vitro and in-vivo endometriosis models. Viability, proliferation and apoptosis were examined. Results: Analysis of 11 public endometriosis bulk transcriptomics databases revealed 2 lists of high confidence and novel druggable targets. Tow novel targets ENDO01 and ENDO02 were selected based on ranking in PandaOmics, consistency of significant dysregulated expression across comparisons, as well as literature evidence relevant to disease-driving mechanisms. Differential expressions were confirmed in human endometriosis tissues. siRNA targeting ENDO01 and ENDO02 significantly reduced cell viability and proliferation, as well as enhanced apoptosis in endometriotic cells in-vitro; and significantly decreased lesion volume and weight with reduced proliferative and enhanced apoptosis in-vivo. Conclusion: Two novel targets for endometriosis were identified with AI and validated by in-vitro and in-vivo experiments within a short period. The study demonstrated how AI could speed up the novel target discovery process from years to months. For diseases remaining incurable or with high morbidity, the application of AI in target discovery could be a new therapeutic regimen that benefits patients.

Liver-Specific Ionizable Lipid Nanoparticles Mediated Efficient RNA Interference to Clear "Bad Cholesterol".

High-level low-density lipoprotein cholesterol (LDL-C) plays a vital role in the development of atherosclerotic cardiovascular disease. Low-density lipoprotein receptors (LDLRs) are scavengers that bind to LDL-C in the liver. LDLR proteins are regulated by proprotein convertase subtilisin/kexin type 9 (PCSK9), which mediates the degradation of LDLR and adjusts the level of the plasma LDL-C. The low expression of PCSK9 leads to the up-regulation of liver LDLRs and the reduction of plasma LDL-C. Hepatocytes are attractive targets for small interfering RNA (siRNA) delivery to silence Pcsk9 gene, due to their significant role in LDL-C regulation. Here, a type of liver-specific ionizable lipid nanoparticles is developed for efficient siRNA delivery. This type of nanoparticles shows high stability, enabling efficient cargo delivery specifically to hepatocytes, and a membrane-active polymer that reversibly masks activity until an acidic environment is reached. Significantly, the siPcsk9 (siRNA targeting to Pcsk9)-loaded nanoparticles (GLP) could silence 90% of the Pcsk9 mRNA in vitro. In vivo study showed that the improved accumulation of GLP in the liver increased LDLR level by 3.35-fold and decreased plasma LDL-C by 35%. GLP has shown a powerful effect on reducing LDL-C, thus providing a potential therapy for atherosclerotic cardiovascular disease.

Zerumbone (ZER), a Potential Anticancer for Breast Mediates Cancer Cell Death Through Targeting β-catenin Signaling Pathway in MCF-7 Cell Line

Background: Zerumbone is a sesquiterpene which was found to delay progression of breast cancer through apoptosis induction via up-regulating Bax protein and down-regulating Bcl2 protein. Purpose: In this study, we aimed to investigate Zerumbone, a natural compound of medicinal herbal plant isolated from Zingiber zerumbet, for anti-cancer activity against MCF-7 cell line. Methods: Human cancer cell lines of breast MCF-7 cells were obtained from American Type Culture Collection (ATCC, Manassas, VA). ON target plus smart pool siRNA, the most efficient method is used for preparation of β-catenin siRNA. Cyclophilin B siRNA is considered as positive control. Zrumbone is an ethanol-soluble compound isolated from Zingiber zerumbet, extracted by the hydro-distillation (steam distillation) method. Purification of ZER was examined using HPLC. The MCF-7 cells transfected with 100 µM human β-catenin (CTNNB1) siRNA or cyclophilin B siRNA positive control. After transfection, the cells were harvested at 48hrs for mRNA analysis or 48 – 72 hrs for protein analysis. IC50 for ZER was determined using MTT assay. MCF-7 transfected with β-catenin siRNA were then treated with ZER IC50. The mRNA expression was analyzed using real-time to ensure the knock down of β-catenin. TUNNEL assay was used to confirm apoptosis and flow cytometry was applied for quantification of apoptotic cells. Western blot analysis was done to evaluate the effect of ZER and β-catenin (CTNNB1) siRNA on the expression of β-catenin and its functional impact on the proliferation and survival of MCF-7 cells. Results: ZER decreased β-catenin protein expression in breast cancer cell lines. ZER downregulated β-catenin mRNA level in breast cancer cell lines. Depletion of β-catenin by β-catenin siRNA and ZER induce cell apoptosis. Apoptosis caused by ZER was confirmed/examined using by annexin V (annexin V was used as a marker for drug action). Conclusion: Zerumbone possesses anti-breast cancer activity, which could be attributed to the reduction of β-catenin protein expression in MCF-7 breast cancer cell lines, downregulation of β-catenin mRNA level in breast cancer cell lines and through annexin V.

Modeling Retinoblastoma in adult Drosophila by reducing Rbf gene expression

Retinoblastoma is an eye cancer that begins in the retina due to genetic mutations in the retinal cells, typically of the Rb1 tumor suppressor gene, which encodes for the Rb protein. Rb inhibits the E2F transcription factor, which drives the expression of genes needed for entry into S-phase of the cell cycle. Loss of function of Rb dysregulates E2F, causing uninhibited cell-cycle proliferation and tumor formation. Current treatments for retinoblastoma are highly invasive such as surgery to remove the eye or chemotherapy impacting patients' lives. If an animal model of retinoblastoma is constructed, less invasive therapies can be tested. Drosophila melanogaster have a short life cycle, are cost-effective, and have an Rb1 homologue called Rbf1, making them an efficient model. An RNAi system was used to knock down the expression of Rbf1 protein via the gsGAL4-UAS gene switch system of gene regulation. A fly line in which the gsGAL4 transcription factor is expressed under the eye-specific elav promoter was crossed with a line in which an siRNA targeting Rbf1 mRNA is expressed under the control of an upstream activating sequence (UAS). When the offspring of this cross were fed RU486, the normally cytoplasmic gsGAL4 entered the nucleus of the retinal cells in which it was expressed and bound to the UAS, driving the expression of the siRNA, which was expected to knock down levels of Rbf1 protein in these flies. RU486-treated flies exhibited a change in eye morphology, suggestive of tumor formation, as well as differential Kaplan-Meier survival curves.

Restoration of Mir-185 in Combination with BCR-ABL Downregulation By Therapeutic Delivery of siRNA with Lipid Nanoparticle Carriers Targets Drug Resistant Leukemic Stem/Progenitor Cells

Background: Despite development of effective tyrosine kinase inhibitors (TKIs) for chronic myeloid leukemia (CML), TKI therapy is not curative as some patients develop drug resistance or are at risk of disease relapse. Importantly, CML leukemic stem cells (LSCs) remain largely unresponsive and represent a key population for sustaining disease and relapse. We previously demonstrated that miR-185 levels were significantly reduced in CD34 + stem/progenitor cells from TKI-nonresponders compared to TKI responders. Further, restoration of miR-185 levels in CML LSCs and their progenitors impaired their survival and sensitized them to TKI in vitro and in vivo. However, the therapeutic potential of downregulating BCR-ABL using siRNA in combination with miR-185 mimic treatment to target CML LSCs have yet to be elucidated. Objective: Downregulation of BCR-ABL using siRNA represents a promising therapeutic approach to inhibit its kinase and non-kinase functions to combat drug-resistant CML and overcome limitations of current therapy. Additionally, previous work suggests that restoring miR-185 levels may improve therapeutic outcomes from complimentary therapies in CML, particularly in combination with BCR-ABL inhibition. Therefore, we aim to investigate the therapeutic outcomes and mechanism of action of inhibiting BCR-ABL using siRNA in combination with miR-185 mimic treatment in drug-resistant CML. Methods: To assess the effects of BCR-ABL downregulation in combination with miR-185 restoration, we encapsulated siRNA targeting BCR-ABL and a miR-185 mimic using an optimized lipid nanoparticle (LNP) formulation. Biological effects and mechanistic changes of this novel RNA combination was evaluated using various CML cell lines expressing b2a2, b3a2, T315I mutated BCR-ABL and CD34 + stem/progenitor cells from non-responder patients. Results: A total of 7 siRNA sequences targeting various fusion regions of BCR-ABL were designed and tested to effectively target primitive CML cells. The highest performing BCR-ABL siRNA encapsulated showed significant knockdown in various CML models expressing b2a2, b3a2 and T315I mutated BCR-ABL (65-99% knockdown). After 48 hours of 0.5 μg/mL BCR-ABL siRNA LNP treatment, BCR-ABL protein levels and its direct downstream target p-CrkL are undetectable by immunoblotting. The robust downregulation of BCR-ABL results in a dose-dependent decrease in cell viability (down to 28% and 9.4% viable cells at a dose of 1 μg/mL) and increase in apoptotic cells (70% and 78% Annexin-V positive) in imatinib resistant K562 and T315I mutated cells, respectively after 72 hours. Similarly, encapsulated miR-185 mimic downregulates its main downstream target PAK6 transcript levels down to 50% in drug sensitive and drug-resistant cell lines and in TKI nonresponder CD34 + stem/progenitor cells. More importantly, our RNA LNP formulation demonstrated significant uptake (> 80% Cy5 positive) of fluorescent-labelled siRNA in TKI nonresponder CD34 + stem/progenitor cells and decreased BCR-ABL mRNA transcript levels by 60%. The combined BCR-ABL inhibition and miR-185 mimic treatment were determined to be highly synergistic when analysed using the Chou-Talalay (combination index less than 1), ZIP, Bliss and HSA methods (synergy scores larger than 10) in both drug-sensitive and drug-resistant CML cells. Furthermore, treatment of BCR-ABL siRNA and miR-185 using LNPs decreased the colony forming units of nonresponder patient cells by 50%. Interestingly, this effect was further enhanced when combined with TKIs, decreasing colony forming units to 20% compared to control after 14 days. Conclusion: We have uncovered a LNP formulation that is able to effectively deliver therapeutic BCR-ABL siRNA and miR-185 mimic into primitive CML cells. This combination treatment significantly reduces the levels of oncogenic BCR-ABL and PAK6, decreasing the viability clonogenic potential and increases apoptosis in CML cell line models and primary patient cells. Importantly, this combination strategy overcomes TKI resistance in CD34 + stem/progenitor cells suggesting a feasible and effective model for patients suffering from clinical resistance and relapse.

NK Cell Dysfunction in CLL Is Mediated through SHP-1 Signaling and Is Associated with Poor Prognosis

Chronic lymphocytic leukemia (CLL) is a heterogeneous disease, presenting with a highly variable clinical course, outcome and response to therapy. This variability has been linked to a complex tumor microenvironment and genetic/epigenetic modifications that lead to immunosuppression. Indeed, the clinical hallmark of this disease is the susceptibility to infections and secondary malignancies. While T cell dysfunction in CLL has been well described, conflicting information exists on NK cell changes in CLL and their role in CLL immunosurveillance. Here, we analyzed samples from 75 untreated (or completed treatment >2 years ago) CLL patients and 30 healthy controls. We discovered a substantial variation in NK cell function compared with healthy controls, which we further classified into hyperfunctional, normofunctional and dysfunctional based on their ability to degranulate, and produce IFN- γ in response to K562 targets ( Figure 1). NK cells from ‘dysfunctional’ CLL samples also displayed impaired cytotoxicity against K562 targets, weaker synapse formation and Syk/Zap70 signaling in response to antibody-dependent cellular cytotoxicity (ADCC) compared to those from ‘functional’ samples. The NK functional status was strongly associated with multiple prognostic markers, including cytogenetics, IgVH mutation status, ZAP-70 expression and disease stage, with patients with dysfunctional NK cells having significantly higher rates of secondary malignancies and viral infections ( Table 1). Using multispectral flow cytometry we discovered high phenotypic heterogeneity with unique NK cell clusters present in the dysfunctional samples. Those clusters express a pattern of activation-induced exhaustion, with upregulation of multiple checkpoint molecules such as PD-1, TIGIT, LAG-3, KLRG-1, TIM-3 but not evidence of terminal differentiation (CD57 negative). Those clusters also showed concomitant expression of activating molecules such as NKG2D and DNAM-1, suggesting reversibility of their dysfunctional status. We subsequently found significantly higher (p<0.0001) constitutive phosphorylation of SHP-1 protein, a phosphatase downstream of multiple inhibitory NK cell receptors, in NK cells from dysfunctional samples. Treatment with a SHP-1 inhibitor NSC-87877 (EMD Millipore) or use of siRNA targeting SHP-1 (ThermoFisher scientific), resulted in reversal of NK dysfunction with full restoration of their functional capacity. Taken together, our data suggest that NK cells functional status plays an important role in CLL disease progression and secondary complications. The novel mechanism of NK cell immune dysfunction in CLL described here has the potential to improve outcomes with novel immunotherapies such as chimeric antigen receptors, checkpoint inhibitors and bi-specific antibody therapy that have shown disappointing results in CLL to date when compared with other B cell malignancies.

Novel Protac-Based EZH2 Degraders Effectively Target EZH2-Driven Lymphoid Malignancies By Abolishing Both Methylation-Dependent and -Independent Functions

Across various cancers, overexpression or mutation of the epigenetic silencer EZH2 correlates with invasive cancer growth, resistance and poor survival outcomes. While the tumorigenic role of EZH2 is largely attributed to the H3K27me3-mediated repression of tumor suppressor genes, reports have also established a methylation-independent role for EZH2 in the transcriptional activation of oncogenes, particularly in aggressive cancers like Natural Killer T-cell Lymphoma (NKTL). Here, traditional EZH2 inhibitors have been ineffective. We hypothesized that targeted depletion of the EZH2 protein will more effectively disrupt oncogenic signals arising from enzyme-independent activities of EZH2. Thus, we embarked on the development of EZH2 Proteolysis Targeting Chimeras (PROTACs) to trigger targeted ubiquitination and proteasome-mediated degradation of EZH2. No clinical EZH2 PROTAC has been reported yet. Our initial efforts focused on the iterative synthesis of a series of PROTAC candidates considering factors such as permeability, solubility and stable ternary complex formation. We developed a library of 53 compounds with various permutations of EZH2- and E3 ligase-binding ligands as well as linker lengths. Through extensive screening and testing of the EZH2 degradation activity via the Nano-Glo HiBiT lytic detection system and immunoblotting, we identified three lead Protac candidates. Compared to the clinical EZH2 inhibitor Tazemetostat (Taz), EZH2 PROTACs, C2911 and C1311 demonstrated higher cytotoxic activity in diffuse large B-cell lymphoma (DLBCL), a cancer in which Taz was evaluated during clinical trial. Importantly, C2911 and C1311 also successfully triggered EZH2 degradation in a dose-dependent manner thereby qualifying for further evaluation in NKTL. Previous work has highlighted a critical role for JAK3-mediated phosphorylation of EZH2 in promoting NKTL proliferation. Treatment of NKTL with C2911 and C1311 leads to a dose and time-dependent EZH2 degradation, loss of cell viability and increased apoptosis. These effects were absent with Taz and Pomalidomide treatments. The concomitant loss of H3K27me3 levels as well as PRC2 complex subunits, SUZ12 and EED suggest effective degradation of the EZH2 protein. We also observed that induction of NKTL cell death required a longer treatment period as compared to DLBCL. This may be potentially ascribed to the longer half-life of the EZH2 protein in NKTL as determined through cycloheximide treatment. In order to validate the mechanism of action of the EZH2 PROTACs, cells were either pretreated with pomalidomide or siRNA targeting cereblon. Indeed, this mitigated PROTAC-induced degradation of the EZH2 protein and rescued cancer cell death. Similarly, inhibiting the activity of the 26S proteasome through bortezomib also prevented EZH2 degradation. Characterization of EZH2 PROTAC-induced protein expression changes through immunoblotting highlighted that there was specific loss of H3K27me3 and H3K27me2 but not H3K27me1. Of note, we detected a concomitant decrease of Jak3 protein expression and STAT5 phosphorylation levels, more pronounced than PRC2 complex subunits. This suggests that the PROTAC may act by disrupting the non-canonical binding of EZH2 to Jak3 in NKTL. Furthermore, gene expression analyses revealed that EZH2 PROTAC treatment more effectively reactivated canonical EZH2 target genes such as MYT1 and ANPEP as compared to Taz. As the JAK-STAT-MYC axis is dysregulated in NK leukemia, we also evaluated the gene expression of c-Myc and c-Myc target gene, E2F1. EZH2 PROTAC treatment reduces the transcription levels of these oncogenes corroborating with loss of c-Myc protein expression. Studying the pharmacokinetics of the lead PROTACs in a mouse model revealed good plasma stability, half-life (> 4 h), and low clearance. Collectively, our data supports a critical role for EZH2 PROTACs in abolishing both the enzyme-dependent and independent activities of EZH2 through protein degradation, resulting in enhanced anti-cancer activity against DLBCL and NKTL. This may potentially benefit other EZH2-driven cancers. Further evaluation of the EZH2 PROTACs for clinical application is in progress. EZH2 PROTACs will next be tested in vivo. An in-depth investigation of the mechanisms stabilizing EZH2 protein levels and underlying PROTAC induced-cell death will be made to identify potential mechanisms of resistance.

Transient receptor potential ankyrin 1 channels in the bladder mediate low temperature elicited bladder overactivity in rats.

This study aimed to investigate whether pathways involving transient receptor potential ankyrin 1 (TRPA1) channels in the urinary bladder mediate the bladder overactivity elicited by exposure to a low temperature in rats. At postnatal week 10, female Sprague-Dawley (SD) rats were intraperitoneally injected with the TRPA1 channel antagonist, HC030031, at room temperature (RT) and subsequently exposed to low temperature (LT). Bladder specimens treated with HC030031 were evaluated for contractions through cumulative addition of the TRPA1 channel agonist trans-cinnamaldehyde. Two days before cystometric investigation, small interfering RNA (siRNA) targeting TRPA1 was transfected into urinary bladders. Then, cystometric investigations were performed on rats subjected to TRPA1 siRNA transfection at both RT and LT. Expression of TRPA1 channels in the urinary bladder was assessed through immunohistochemistry and real-time reverse transcription-polymerase chain reaction. At RT, micturition patterns were unaffected by HC030031 treatment. However, upon exposure to LT, rats treated with HC030031 exhibited a reduction of LT-elicited bladder overactivity, as evidenced by inhibited decreases in voiding interval, micturition volume, and bladder capacity. Additionally, HC030031 inhibited trans-cinnamaldehyde-induced contractions. Immunohistochemical analysis showed the presence of TRPA1 channels in the urinary bladder. Notably, rats with TRPA1 siRNA-transfected bladders could partially inhibit bladder overactivity during LT exposure. These findings indicate that pathways involving TRPA1 channels expressed in the urinary bladder could mediate the LT-elicited bladder overactivity.

ZBTB20 mediates stress-induced visceral hypersensitivity via activating the NF-κB/transient receptor potential channel pathway.

Psychological stress is a major trigger for visceral hypersensitivity (VH) in irritable bowel syndrome. The zinc finger protein ZBTB20 (ZBTB20) is implicated in somatic nociception via modulating transient receptor potential (TRP) channels, but its role in the development of VH is unclear. This study aimed to investigate the role of ZBTB20/TRP channel axis in stress-induced VH. Rats were subjected to water avoidance stress (WAS) for 10 consecutive days. Small interfering RNA (siRNA) targeting ZBTB20 was intrathecally administered. Inhibitors of TRP channels, stress hormone receptors, and nuclear factor kappa-B (NF-κB) were administered. Visceromotor response to colorectal distension was recorded. Dorsal root ganglia (DRGs) were dissected for Western blot, coimmunoprecipitation, and chromatin immunoprecipitation. The DRG-derived neuron cell line was applied for specific research. WAS-induced VH was suppressed by the inhibitor of TRPV1, TRPA1, or TRPM8, with enhanced expression of these channels in L6-S2 DRGs. The inhibitor of glucocorticoid receptor or β2-adrenergic receptor counteracted WAS-induced VH and TRP channel expression. Concurrently, WAS-induced stress hormone-dependent ZBTB20 expression and NF-κB activation in DRGs. Intrathecally injected ZBTB20 siRNA or an NF-κB inhibitor repressed WAS-caused effect. In cultured DRG-derived neurons, stress hormones promoted nuclear translocation of ZBTB20, which preceded p65 nuclear translocation. And, ZBTB20 siRNA suppressed stress hormone-caused NF-κB activation. Finally, WAS enhanced p65 binding to the promoter of TRPV1, TRPA1, or TRPM8 in rat DRGs. ZBTB20 mediates stress-induced VH via activating NF-κB/TRP channel pathway in nociceptive sensory neurons.

M6PR interacts with the HA2 subunit of influenza A virus to facilitate the fusion of viral and endosomal membranes.

Influenza A virus (IAV) commandeers numerous host cellular factors for successful replication. However, very few host factors have been revealed to be involved in the fusion of viral envelope and late endosomal membranes. In this study, we identified cation-dependent mannose-6-phosphate receptor (M6PR) as a crucial host factor for the replication of IAV. We found that siRNA knockdown of M6PR expression significantly reduced the growth titers of different subtypes of IAV, and that the inhibitory effect of M6PR siRNA treatment on IAV growth was overcome by the complement of exogenously expressed M6PR. When A549 cells were treated with siRNA targeting M6PR, the nuclear accumulation of viral nucleoprotein (NP) was dramatically inhibited at early timepoints post-infection, indicating that M6PR engages in the early stage of the IAV replication cycle. By investigating the role of M6PR in the individual entry and post-entry steps of IAV replication, we found that the downregulation of M6PR expression had no effect on attachment, internalization, early endosome trafficking, or late endosome acidification. However, we found that M6PR expression was critical for the fusion of viral envelope and late endosomal membranes. Of note, M6PR interacted with the hemagglutinin (HA) protein of IAV, and further studies showed that the lumenal domain of M6PR and the ectodomain of HA2 mediated the interaction and directly promoted the fusion of the viral and late endosomal membranes, thereby facilitating IAV replication. Together, our findings highlight the importance of the M6PR-HA interaction in the fusion of viral and late endosomal membranes during IAV replication.

Development of multifunctional pyrrole-imidazole polyamides that increase hepatocyte growth factor and suppress transforming growth factor-β1

PurposeThe DNA recognition peptide compounds pyrrole-imidazole (PI) polyamides bind to the minor groove and can block the binding of transcription factors to target sequences. To develop more PI polyamides as potential treatments for fibrotic diseases, including chronic renal failure, we developed multifunctional PI polyamides that increase hepatocyte growth factor (HGF) and decrease transforming growth factor (TGF)-β1. MethodsWe designed seven PI polyamides (HGF-1 to HGF-7) that bind to the chicken ovalbumin upstream promoter transcription factor-1 (COUP-TF1) binding site of the HGF promoter sequence. We selected PI polyamides that increase HGF and suppress TGF-β1 in human dermal fibroblasts (HDFs). FindingsGel shift assays showed that HGF-2 and HGF-4 bound the appropriate dsDNAs. HGF-2 and HGF-4 significantly inhibited the TGF-β1 mRNA expression in HDFs stimulated by phorbol 12-myristate 13-acetate. HGF-2 and HGF-4 significantly inhibited the TGF-β1 protein expression in HDFs with siRNA targeting HGF, indicating that HGF-2 and HGF-4 directly inhibited the expression of TGF-β1. ConclusionThe designed and synthetic HGF PI polyamides targeting the HGF promoter, which increased the expression of HGF and suppressed the expression of TGF-β, will be a potential practical medicine for fibrotic diseases, including progressive renal diseases.

MCT Nanoemulsions for the Efficient Delivery of siRNA

In this study, an oil-in-water (o/w) nanoemulsion is used to deliver siRNA targeting Twist1, a protein that contributes to tumor metastasis in a variety of cancers. The FDA-approved oil, medium chain triglycerides (MCT), is used as the hydrophobic phase for the nanoemulsion. The siRNA is paired with dioleoyl-3-trimethylammonium-propane (DOTAP) to form a hydrophobic salt that is soluble at high concentrations in MCT. The resulting MCT/siRNA-DOTAP solution is formulated into a nanoemulsion with an average particle size of 140 nm. The nanoemulsion displays long term stability over the course of 195 days. In an in vivo murine tumor model, the nanoemulsion facilitates a 46% decrease in Twist1 mRNA after 48 h.

Design of knowledge-based mechanistic model of atherosclerotic cardiovascular disease for in silico trials

Abstract In silico trials applying a computational model (CM) of atherosclerotic cardiovascular disease (ASCVD) to virtual patients receiving alternative treatments provide an attractive option to complement randomised clinical trials (RCTs) by adding comparative effectiveness data and facilitating the demonstration of drug benefit. In silico modelling allows comparison between treatments with each virtual patient being his own control, and is not limited by the number of patients, comparative arms or trial duration. This study aims at building a knowledge-based mechanistic model of ASCVD. Once validated, the model will be used to run in silico clinical trials to compare the benefit of inclisiran, an siRNA targeting PCSK9 mRNA, vs other lipid-lowering therapies (LLT) on cardiovascular (CV) events in patients with ASCVD. An extensive literature review was performed to identify pathophysiological mechanisms involved in ASCVD and therapeutic mechanisms of action (MOAs). Every piece of knowledge extracted from the literature is awarded a strength of evidence grading to allow tracking of uncertainty in the model. A panel of multidisciplinary experts reviewed knowledge models and subsequent modelling hypotheses to validate their relevance. Knowledge was translated into mathematical equations. Each functional relationship between entities is represented by a biochemical/biophysical reaction with its reaction rate. A system of ordinary differential equations provides dynamics of modelled biological entities. A strategy of model calibration/validation was defined with the expert panel, by selecting relevant RCT and registry data, that the model should be able to reproduce. A virtual population was generated to account for inter-patient variability. A mechanistic CM of ASCVD (including 72 biological entities, 750 parameters) was built from knowledge, describing lipoproteins metabolism and cholesterol homeostasis, dynamics of atherosclerotic plaque growth with lipoproteins infiltration in the intima and evolution of lipidic, necrotic and fibrotic tissues as well as plaque rupture leading to myocardial infarction, ischemic stroke, lower extremity arterial disease or CV death. It also includes the impact of several risk factors (age, sex medical history, diabetes, hypertension, smoking, systemic inflammation, chronic kidney disease) and available LLT (atorvastatin, rosuvastatin, ezetimibe, evolocumab and inclisiran). After calibration, the model and virtual population reproduce pharmacokinetics of LLT, lipoproteins decrease under combinations of LLT and associated reduction in clinical events. ASCVD is ideally suited for in silico modelling: extensive literature is available regarding the pathophysiology, therapeutic MOAs are known and easily integrated in the model, clinically relevant outcomes are adequate model outputs, RCT and registry data exist to calibrate/validate the model. The next step is validation of the model before using it to run in silico trials.Plaque growth and rupture modelMulti-scale in silico model

SiRNA Targeting PDE5A Partially Restores Vascular Damage Due to Type 1 Diabetes in a Streptozotocin-Induced Rat Model

Diabetes mellitus is a metabolic disease that can produce different alterations such as endothelial dysfunction, which is defined as a decrease in the vasodilator responses of the mechanisms involved such as the nitric oxide (NO) pathway. The overexpression of PDE5A has been reported in diabetes, which causes an increase in the hydrolysis of cGMP and a decrease in the NO pathway. For this reason, the aim of this study was to evaluate whether siRNAs targeting PDE5A can reduce the endothelial dysfunction associated with diabetes. We used male Wistar rats (200–250 g) that were administered streptozotocin (STZ) (60 mg/kg i.p) to induce diabetes. Two weeks after STZ administration, the siRNAs or vehicle were administered and then, at 4 weeks, dose–response curves to acetylcholine were performed and PDE5A mRNA levels were measured by RT-PCR. siRNAs were designed by the bioinformatic analysis of human–rat FASTA sequences and synthesised in the Mermade-8 equipment. Our results showed that 4 weeks of diabetes produces a decrease in the vasodilator responses to acetylcholine and an increase in the expression of PDE5A mRNA, while the administration of siRNAs partially restores the vasodilator response and decreases PDE5A expression. We conclude that the administration of siRNAs targeting PDE5A partially reverts the endothelial impairment associated with diabetes.

Abstract 12705: Identification and Characterization of Solbinsiran, a GalNAc Conjugated siRNA Targeting Angiopoietin-Like 3

Introduction: While statins play an important role in reducing LDL-C levels and the risk of ASCVD events, residual risk from apolipoprotein B (apoB)-containing lipoprotein particles persists among patients with or at high risk of ASCVD. Hypothesis: Blocking ANGPTL3 activity or preventing its expression is a therapeutic approach to reduce apoB-containing lipoprotein particles. Solbinsiran (LY3561774), a novel Dicer-substrate small interfering RNA oligonucleotide, was designed to reduce the levels of ANGPTL3 protein expression. Methods: Nucleotide base sequences of a library of anti-ANGPTL3 siRNAs were selected using an in silico RNAi prediction algorithm on ANGPTL3 mRNA sequences conserved in humans and cynomolgus monkeys. Through a large-scale in vitro screen of the anti-ANGPTL3 library in human cells, the candidate solbinsiran sequence was identified as an efficacious siRNA. Solbinsiran in vivo efficacy was measured by RT-qPCR of liver from CD-1 female mice overexpressing human ANGPTL3 . The degree and durability of ANGPTL3 mRNA knockdown and circulating protein level reduction by solbinsiran was evaluated in cynomolgus monkeys administered single dose subcutaneous injections of either PBS or 3 mg/kg solbinsiran. Blood samples to measure ANGPTL3 protein were collected on Study Days -8, -5, and 0, and weekly after dosing until Day 113. Ultrasound-guided core needle liver biopsies were collected on Study Days 5, 28, 56, 84, and 113. Total RNA derived from the liver biopsy samples to measure ANGPTL3 mRNA was subjected to RT-qPCR analysis. Results: When given a single dose at 1 mg/kg subcutaneously, solbinsiran reduced human ANGPTL3 mRNA by 65% in hepatocytes as compared to vehicle-treated mice. A single dose of solbinsiran reduced liver ANGPTL3 mRNA expression by up to 72.9% (p<0.0001) and serum ANGPTL3 protein expression by 68.6% (p<0.001). Solbinsiran also displayed a long duration of activity, as indicated by a greater than 50% mRNA knockdown remaining 12 weeks after a single dose. Conclusions: These data supported the advancement of solbinsiran to Phase 1 clinical testing in participants with mixed dyslipidemia (ClinicalTrials.gov Identifier: NCT04644809).

Abstract 13757: Suppression of Ischemia-Hypoxia Reperfusion Injury in Human iPS Cell-Derived Cardiomyocytes Through Downregulation of EGR1 Mediated by miR-124-3p

Background: Ischemic heart diseases are one of the leading causes of death globally. Although timely revascularization is performed, some cases may still result in heart failure due to ischemia-hypoxia reperfusion (IH/R) injury. Early growth response 1 (EGR1) was reported to involved in reperfusion injury, but its specific role in IH/R-induced apoptosis in human cardiomyocytes (CMs) remains unexplored. Hypothesis: EGR1 is involved in the exacerbation of the IH/R-mediated apoptosis in human CMs, and miR-124-3p acts as an antagonist of EGR1. Methods: Human induced pluripotent stem cell (hiPSC)-derived CMs were cultured in serum-free low-glucose medium with a hypoxic chamber. EGR1 expression and the extent of apoptosis were evaluated by qRT-PCR, Western blotting (WB), and immunofluorescent assay (IFA). RNA-seq was conducted to identify specific pathways. SiRNA targeting EGR1 and miR-124-3p mimic were used to downregulate EGR1 under IH/R. Results: qRT-PCR (Control vs IH/R: 1.000 ± 0.000 vs 5.749 ± 2.947; P<0.01) and WB (0.037 ±0.038 vs 0.953 ± 0.306; P<0.0001) analyses revealed higher expression of EGR1 in IH/R group. IFA demonstrated a higher ratio of cleaved Caspase-3-positive apoptotic cells in IH/R group (0.202 ±0.206 vs 0.377 ± 0.252; P<0.001). RNA-seq analysis indicated significant downregulation of pathways related to cell survival in IH/R. The siRNA downregulated EGR1 successfully, as confirmed by qRT-PCR, WB, and IFA (IH/R Water vs IH/R siRNA: 0.612 ±0.307 vs 0.257 ±0.122; P<0.01), which led to the suppression of apoptosis (0.288 ±0.143 vs 0.142 ±0.049; P<0.05). miR-124-3p mimic downregulated EGR1 under IH/R conditions, as shown by PCR (IH/R Water vs IH/R miRNA mimic: 3.731 ±1.126 vs 2.568 ±0.959; P<0.0001) and WB (0.947 ±0.438 vs 0.478 ±0.277; P<0.05). IFA proved the suppression of EGR1 by miR-124-3p mimic (0.414 ±0.101 vs 0.062 ±0.064; P<0.0001), which subsequently reduced CM apoptosis (0.234 ±0.127 vs 0.092 ±0.047; P<0.001). Conclusion: EGR1 participate in exacerbating apoptosis mediated by IH/R in human CMs. The downregulation of EGR1 suppresses IH/R-induced apoptosis. Treatment with miR-124-3p targeting EGR1 may potentially serve as a novel therapeutic approach for cardioprotection in the future.

Abstract 17047: Contribution of MDA-5/IL-10RA to Pulmonary Artery Homeostasis and Pulmonary Arterial Hypertension

Introduction: Pulmonary arterial hypertension (PAH) is a progressive and lethal disease. The current treatment options do not target pulmonary artery endothelial cell (PAEC) dysfunction. We have previously shown a role for the endosomal double stranded (ds) RNA receptor toll-like receptor 3 (TLR3) and its regulation via interleukin-10 (IL-10) in promoting PAEC dysfunction and experimental pulmonary hypertension (PH). Yet the role of the cytosolic dsRNA receptor melanoma differentiation factor 5 (MDA-5) in endothelial dysfunction is not known. Hypothesis: We hypothesized that a deficient MDA-5/IL-10 receptor A (IL-10RA) signaling axis expression exists in PAH PAECs as a potential cause of endothelial dysfunction. Goals: Our goal is to test the role of a potential new axis of MDA-5 and IL10RA in EC homeostasis and pulmonary hypertension. Methods: Western blot analysis of control and PAH PAECs and PA smooth muscle cells (SMCs) was conducted. Gene silencing was done using siRNA targeting MDA-5 and IL-10RA, followed by bulk RNA sequencing. Apoptosis was tested using Annexin V binding. IL-10 whole body knockout (IL-10 -/- ) and endothelial-specific IL-10RA haploinsufficient mice (IL-10RA fl/wt Cdh5-Cre + ) and appropriate controls were exposed to chronic hypoxia and SU5416 (Hx/Su), followed by hemodynamics. Results: Our data show a reduction of MDA-5 in PAECs, but not in PASMCs. PAH PAECs further had reduced IL-10RA expression and application of dsRNA elevated IL-10RA expression in PAH PAECs. Knockdown of MDA-5 and IL-10RA caused differential expression of 2533 and 2638 genes, respectively. Comparative analysis revealed an overlap of differentially expressed genes (DEGs) in canonical pathways including reduced nitric oxide, VEGF, Apelin and Integrin signaling. Comparison also yielded overlapping DEGs for reduced cell survival, impaired cytoskeleton organization and migration. Gene silencing of MDA-5 resulted in increased PAEC apoptosis. IL-10 -/- and IL-10RA fl/wt Cdh5-Cre + mice showed exaggerated PH. Conclusions: Our data indicate an impaired cytosolic dsRNA receptor MDA-5 and IL-10RA axis in PAH PAECs which contributes to endothelial dysfunction and PH. Experiments are underway to identify the detailed mechanisms underlying our findings.