Neurofibromin Deficiency Causes Epidermal Growth Factor Receptor Upregulation through the Activation of Ras/ERK/SP1 Signaling Pathway in Neurofibromatosis Type 1-Associated Malignant Peripheral Nerve Sheet Tumor

Neurofibromatosis type 1 (NF1) is an autosomal dominant human genetic disorder. The progression of benign plexiform neurofibromas to malignant peripheral nerve sheet tumors (MPNSTs) is a major cause of mortality in patients with NF1. Although elevated epidermal growth factor receptor (EGFR) expression plays a crucial role in the pathogenesis of MPNST, the cause of EGFR overexpression remains unclear. Here, we assessed EGFR expression levels in MPNST tissues of NF1 patients and NF1 patient-derived MPNST cells. We found that the expression of EGFR was upregulated in MPNST tissues and MPNST cells, while the expression of neurofibromin was significantly decreased. Manipulation of NF1 expression by NF1 siRNA treatment or NF1-GAP-related domain overexpression demonstrated that EGFR expression levels were closely and inversely correlated with neurofibromin levels. Notably, knockdown of the NF1 gene by siRNA treatment augmented the nuclear localization of phosphorylated SP1 (pSP1) and enhanced pSP1 binding to the EGFR gene promoter region. Our results suggest that neurofibromin deficiency in NF1-associated MPNSTs enhances the Ras/ERK/SP1 signaling pathway, which in turn may lead to the upregulation of EGFR expression. This study provides insight into the progression of benign tumors and novel therapeutic approaches for treatment of NF1-associated MPNSTs.

459 Evaluation of LDL-C reductions by siRNA treatment with inclisiran in patients with diabetes mellitus, metabolic syndrome or neither

Aims Patients with diabetes (DM) and metabolic syndrome (MS) have elevated risks for atherosclerotic cardiovascular disease (ASCVD). Aggressive LDL-C lowering reduces risks. Inclisiran, a new siRNA, lowers LDL-C and was evaluated in patients with Type 2 diabetes (DM), metabolic syndrome (MS) without DM or neither (N) in the ORION-10 trial. Methods ORION-10 was a double-blind, randomized, placebo controlled trial evaluating inclisiran in 1561 patients with ASCVD on maximally tolerated therapy for lowering LDL-C. 781 inclisiran (INC) participants and 780 placebo (P) patients received 1.5 mL SQ tx at Days 1, 90, then every 6 months until Day 540. We evaluated the time adjusted change in LDL-C from baseline after Days 90–540 in DM (n = 702), MS (n = 455) and N participants (n = 404). Results There were no differences in baseline demographics and background therapies between INC and P. Statins were utilized in 89.8% INC and 88.7% of P. High intensity statins were utilized in 67.2% of INC and 68.8% of P; ezetimibe in 10.2% of NC and 9.5% of P participants. INC reduced LDL-C by − 54.4% (−58.3, −50.6 95% CI) in DM, (P < 0.001), −58.6% (−62.3, −54.8), P < 0.001 in-MS and −56.0% (−60.2, −51.7), in N subjects P < 0.001 (see Figure). Conclusions Inclisiran potently and durably reduces LDL-C across patients with DM, MS and those with neither, demonstrating potent efficacy and durability across glycaemic categories. Inclisiran may also represent a potent LDL-C lowering treatment for those with DM and MS.

Apomorphine Reduces A53T α-Synuclein-Induced Microglial Reactivity Through Activation of NRF2 Signalling Pathway

The chiral molecule, apomorphine, is currently used for the treatment of Parkinson’s disease (PD). As a potent dopamine receptor agonist, this lipophilic compound is especially effective for treating motor fluctuations in advanced PD patients. In addition to its receptor-mediated actions, apomorphine has also antioxidant and free radical scavenger activities. Neuroinflammation, oxidative stress, and microglia reactivity have emerged as central players in PD. Thus, modulating microglia activation in PD may be a valid therapeutic strategy. We previously reported that murine microglia are strongly activated upon exposure to A53T mutant α-synuclein. The present study was designed to investigate whether apomorphine enantiomers could modulate this A53T-induced microglial activation. Taken together, the results provided evidence that apomorphine enantiomers decrease A53T-induced microgliosis, through the activation of the NRF2 signalling pathway, leading to a lower pro-inflammatory state and restoring the phagocytic activity. Suppressing NRF2 recruitment (trigonelline exposure) or silencing specifically Nfe2l2 gene (siRNA treatment) abolished or strongly decreased the anti-inflammatory activity of apomorphine. In conclusion, apomorphine, which is already used in PD patients to mimic dopamine activity, may also be suitable to decrease α-synuclein-induced microglial reactivity.

Oral Administration of Ginger-Derived Lipid Nanoparticles and Dmt1 siRNA Potentiates the Effect of Dietary Iron Restriction and Mitigates Pre-Existing Iron Overload in Hamp KO Mice

Intestinal iron transport requires an iron importer (Dmt1) and an iron exporter (Fpn1). The hormone hepcidin regulates iron absorption by modulating Fpn1 protein levels on the basolateral surface of duodenal enterocytes. In the genetic, iron-loading disorder hereditary hemochromatosis (HH), hepcidin production is low and Fpn1 protein expression is elevated. High Fpn1-mediated iron export depletes intracellular iron, causing a paradoxical increase in Dmt1-mediated iron import. Increased activity of both transporters causes excessive iron absorption, thus initiating body iron loading. Logically then, silencing of intestinal Dmt1 or Fpn1 could be an effective therapeutic intervention in HH. It was previously established that Dmt1 knock down prevented iron-loading in weanling Hamp (encoding hepcidin) KO mice (modeling type 2B HH). Here, we tested the hypothesis that Dmt1 silencing combined with dietary iron restriction (which may be recommended for HH patients) will mitigate iron loading once already established. Accordingly, adult Hamp KO mice were switched to a low-iron (LFe) diet and (non-toxic) folic acid-coupled, ginger nanoparticle-derived lipid vectors (FA-GDLVs) were used to deliver negative-control (NC) or Dmt1 siRNA by oral, intragastric gavage daily for 21 days. The LFe diet reduced body iron burden, and experimental interventions potentiated iron losses. For example, Dmt1 siRNA treatment suppressed duodenal Dmt1 mRNA expression (by ~50%) and reduced serum and liver non-heme iron levels (by ~60% and >85%, respectively). Interestingly, some iron-related parameters were repressed similarly by FA-GDLVs carrying either siRNA, including 59Fe (as FeCl3) absorption (~20% lower), pancreatic non-heme iron (reduced by ~65%), and serum ferritin (decreased 40–50%). Ginger may thus contain bioactive lipids that also influence iron homeostasis. In conclusion, the combinatorial approach of FA-GDLV and Dmt1 siRNA treatment, with dietary iron restriction, mitigated pre-existing iron overload in a murine model of HH.

Low-density Lipoprotein-Cholesterol Lowering Strategies for Prevention of Atherosclerotic Cardiovascular Disease: Focus on siRNA Treatment Targeting PCSK9 (Inclisiran)

Purpose of Review The aim of low-density lipoprotein-cholesterol (LDL-C) lowering therapies is to safely achieve a consistent and long-term reduction in exposure of the vasculature to atherogenic lipoproteins in order to reduce the risk of atherosclerotic cardiovascular (CV) disease and the associated CV events, such as myocardial infarctions and ischemic strokes. This review summarizes the concept and clinical development of a novel molecular approach to efficiently lower LDL-C, a synthetic small interfering ribonucleic acid (siRNA)—inclisiran—directed against proprotein convertase subtilisin-kexin type 9 (PCSK9). Recent Findings The understanding of genes regulating atherogenic lipoproteins and their causal role in the development of atherosclerotic CV disease has substantially advanced over the past years. This has opened the possibility for development of molecular therapies targeting these atherogenic lipoproteins, in particular by RNA-targeted treatment approaches. The most advanced clinical development program is the siRNA-treatment targeting PCSK9 (inclisiran), involving more than 4000 patients in clinical studies. Phase 1 and 2 studies have identified the dose of 300 mg inclisiran for efficient LDL-C lowering. Most recently, three phase 3 studies demonstrated that a regimen of inclisiran every 6 months was feasible and reduced LDL-C by approximately 50% in patients at high or very high CV risk or with familial hypercholesterolemia. Adverse events were similar in the inclisiran and the placebo groups, except for more frequent transient injection site reactions with inclisiran than with placebo. Summary siRNA therapy targeting PCSK9 (inclisiran) applied twice a year efficiently reduced LDL-C by approximately 50% and was safe in recent phase 3 studies. The effects of this treatment on CV outcome are currently further assessed in a large ongoing CV outcome trial.

(Pro)renin receptor promotes crescent formation via the ERK1/2 and Wnt/β-catenin pathways in glomerulonephritis

(Pro)renin receptor [(P)RR] has multiple functions, but its regulation and role in the pathogenesis in glomerulonephritis (GN) are poorly defined. The aims of the present study were to determine the effects of direct renin inhibition (DRI) and demonstrate the role of (P)RR on the progression of crescentic GN. The anti-glomerular basement membrane nephritis rat model developed progressive proteinuria (83.64 ± 10.49 mg/day) and glomerular crescent formation (percent glomerular crescent: 62.1 ± 2.3%) accompanied by increased macrophage infiltration and glomerular expression of monocyte chemoattractant protein (MCP)-1, (P)RR, phospho-extracellular signal-regulated kinase (ERK)1/2, Wnt4, and active β-catenin. Treatment with DRI ameliorated proteinuria (20.33 ± 5.88 mg/day) and markedly reduced glomerular crescent formation (20.9 ± 2.6%), induction of macrophage infiltration, (P)RR, phospho-ERK1/2, Wnt4, and active β-catenin. Furthermore, primary cultured parietal epithelial cells stimulated by recombinant prorenin showed significant increases in cell proliferation. Notably, while the ERK1/2 inhibitor PD98059 or (P)RR-specific siRNA treatment abolished the elevation in cell proliferation, DRI treatment did not abrogate this elevation. Moreover, cultured mesangial cells showed an increase in prorenin-induced MCP-1 expression. Interestingly, (P)RR or Wnt4-specific siRNA treatment or the β-catenin antagonist XAV939 inhibited the elevation of MCP-1 expression, whereas DRI did not. These results suggest that (P)RR regulates glomerular crescent formation via the ERK1/2 signaling and Wnt/β-catenin pathways during the course of anti-glomerular basement membrane nephritis and that DRI mitigates the progression of crescentic GN through the reduction of (P)RR expression but not inhibition of prorenin binding to (P)RR.

Enhancing Chemotherapy by RNA Interference

Small interfering RNA (siRNA) has shown tremendous potential for treating human diseases in the past decades. siRNA can selectively silence a pathological pathway through the targeting and degradation of a specific mRNA, significantly reducing the off-target side effects of anticancer drugs. However, the poor pharmacokinetics of RNA significantly restricted the clinical use of RNAi technology. In this review, we examine in-depth the siRNA therapeutics currently in preclinical and clinical trials, multiple challenges faced in siRNA therapy, feasibility of siRNA treatment with anticancer drugs in combined with siRNA in nanoparticles or modified to be parental drugs, sequential therapy of siRNA treatment prior to drug treatment with siRNA and drugs loaded in nanoparticles. We focused on the combinatorial activation of apoptosis by different pathways, namely Bcl-2, survivin, and Pgp protein. Taken together, this review would serve to establish the pathway of effective and efficient combination therapy of siRNA and drugs as a new strategy.