PLGA microspheres encapsulating siRNA anti-TNFalpha: efficient RNAi-mediated treatment of arthritic joints

siRNA-based nanotherapeutic approaches for targeted delivery in rheumatoid arthritis

Rheumatoid arthritis (RA), characterized as a systemic autoimmune ailment, predominantly results in substantial joint and tissue damage, affecting millions of individuals globally. Modern treatment modalities are being explored as the traditional RA therapy with non-specific immunosuppressive drugs showcased potential side effects and variable responses. Research potential with small interfering RNA (siRNA) depicted potential in the treatment of RA. These siRNA-based therapies could include genes encoding pro-inflammatory cytokines like TNF-α, IL-1, and IL-6, as well as other molecular targets such as RANK, p38 MAPK, TGF-β, Wnt/Fz complex, and HIF. By downregulating the expression of these genes, siRNA-based nanoformulations can attenuate inflammation, inhibit immune system dysregulation, and prevent tissue damage associated with RA. Strategies of delivering siRNA molecules through nanocarriers could be targeted to treat RA effectively, where specific genes associated with this autoimmune disease pathology can be selectively silenced. Additionally, simultaneous targeting of multiple molecular pathways may offer synergistic therapeutic benefits, potentially leading to more effective and safer therapeutic strategies for RA patients. This review critically highlights the in-depth pathology of RA, RNA interference-mediated molecular targets, and nanocarrier-based siRNA delivery strategies, along with the challenges and opportunities to harbor future solutions.

Nebulised delivery of RNA formulations to the lungs: From aerosol to cytosol

In the past decade RNA-based therapies such as small interfering RNA (siRNA) and messenger RNA (mRNA) have emerged as new and ground-breaking therapeutic agents for the treatment and prevention of many conditions from viral infection to cancer. Most clinically approved RNA therapies are parenterally administered which impacts patient compliance and adds to healthcare costs. Pulmonary administration via inhalation is a non-invasive means to deliver RNA and offers an attractive alternative to injection. Nebulisation is a particularly appealing method due to the capacity to deliver large RNA doses during tidal breathing. In this review, we discuss the unique physiological barriers presented by the lung to efficient nebulised RNA delivery and approaches adopted to circumvent this problem. Additionally, the different types of nebulisers are evaluated from the perspective of their suitability for RNA delivery. Furthermore, we discuss recent preclinical studies involving nebulisation of RNA and analysis in in vitro and in vivo settings. Several studies have also demonstrated the importance of an effective delivery vector in RNA nebulisation therefore we assess the variety of lipid, polymeric and hybrid-based delivery systems utilised to date. We also consider the outlook for nebulised RNA medicinal products and the hurdles which must be overcome for successful clinical translation. In summary, nebulised RNA delivery has demonstrated promising potential for the treatment of several lung-related conditions such as asthma, COPD and cystic fibrosis, to which the mode of delivery is of crucial importance for clinical success.

Pathophysiology to advanced intra-articular drug delivery strategies: Unravelling rheumatoid arthritis

Rheumatoid arthritis (RA) is one of the most prevalent life-long autoimmune diseases with an unknown genesis. It primarily causes chronic inflammation, pain, and synovial joint-associated cartilage and bone degradation. Unfortunately, limited information is available regarding the etiology and pathogenesis of this chronic joint disorder. In the last few decades, an improved understanding of RA pathophysiology about key immune cells, antibodies, and cytokines has inspired the development of several anti-rheumatic drugs and biopharmaceuticals to act on RA-affected joints. However, life-long frequent systemic high doses of commercially available drugs are currently a limiting factor in the efficient management of RA. To address this issue, various single and double-barrier intra-articular drug delivery systems (IA-DDSs) such as nanocarriers, microparticles, hydrogels, and particles-hybrid hydrogel composite have been developed which can exclusively target the RA-affected joint cavity and release the precisely controlled therapeutic drug concentration for prolonged time whilst avoiding the systemic toxicity. This review provides a comprehensive overview of the pathogenesis of RA and discusses the rational design and development of biomaterials-based novel IA-DDs, ranging from conventional to advanced systems, for improved treatment of RA. Therefore, this review aims to unravel the pathophysiology of rheumatoid arthritis and explore cutting-edge IA-DD strategies exploiting biomaterials. It offers researchers a consolidated and up-to-date resource platform to analyze existing knowledge, identify research gaps, and contribute to the scientific literature.

PLGA implants for controlled drug release: Impact of the diameter

The aim of this study was to better understand the importance of the diameter of poly(lactic-co-glycolic acid) (PLGA)-based implants on system performance, in particular the control of drug release. Different types of ibuprofen-loaded implants were prepared by hot melt extrusion using a Leistritz Nano 16 twin-screw extruder. Drug release was measured in well agitated phosphate buffer pH7.4 bulk fluid and in agarose gels in Eppendorf tubes or transwell plates. Dynamic changes in the implants' dry & wet mass, volume, polymer molecular weight as well as inner & outer morphology were monitored using gravimetric analysis, optical macroscopy, gel permeation chromatography and scanning electron microscopy. The physical states of the drug and polymer were determined by DSC. Also pH changes in the release medium were investigated. Irrespective of the type of experimental set-up, the resulting absolute and relative drug release rates decreased with increasing implant diameter (0.7 to 2.8 mm). Bi-phasic drug release was observed in all cases from the monolithic solutions (ibuprofen was dissolved in the polymer): A zero order release phase was followed by a final, rapid drug release phase (accounting for 80-90% of the total drug dose). The decrease in the relative drug release rate with increasing system diameter can be explained by the increase in the diffusion pathway lengths to be overcome. Interestingly, also the onset of the final rapid drug release phase was delayed with increasing implant diameter. This can probably be attributed to the higher mechanical stability of thicker devices, offering more resistance to substantial entire system swelling.

Long-acting microspheres of Human Chorionic Gonadotropin hormone: In-vitro and in-vivo evaluation

Human Chorionic Gonadotropin (hCG) hormone is used to cause ovulation, treat infertility in women, and increase sperm count in men. Conventional hCG solution formulations require multiple administration of hCG per week and cause patient noncompliance. The long-acting PLGA depot microspheres (MS) approach with hCG can improve patient compliance, increase the efficacy of hCG with a lower total dose and improve quality of life. Therefore, hCG was encapsulated by a modified double emulsion solvent evaporation technique within PLGA MS by high-speed homogenizer and industrially scalable in-line homogenizer, respectively. MS was characterized for particle size, encapsulation efficiency (EE), surface morphology, and in-vitro release. The spherical, dense, non-porous microspheres were obtained with a size of 58.88 ± 0.18 µm. Microspheres showed high EE (77.4% ± 5.9%) with low initial burst release (12.82% ± 2.07%). Circular Dichroism and SDS-PAGE analysis indicated good stability and structural integrity of hCG in the microspheres. Its bioactivity was proven further by a bioassay study in immature Wistar rats. Pharmacokinetic analysis showed that the hCG PLGA MS maintained serum hCG concentration up to 13 days compared to multiple injections of a marketed conventional parenteral injectable formulation of hCG. Thus, it can be ascertained that the hCG PLGA MS may have great potential for clinical use in long-term therapy.

Delivery of Wnt inhibitor WIF1 via engineered polymeric microspheres promotes nerve regeneration after sciatic nerve crush

Injuries within the peripheral nervous system (PNS) lead to sensory and motor deficits, as well as neuropathic pain, which strongly impair the life quality of patients. Although most current PNS injury treatment approaches focus on using growth factors/small molecules to stimulate the regrowth of the injured nerves, these methods neglect another important factor that strongly hinders axon regeneration-the presence of axonal inhibitory molecules. Therefore, this work sought to explore the potential of pathway inhibition in promoting sciatic nerve regeneration. Additionally, the therapeutic window for using pathway inhibitors was uncovered so as to achieve the desired regeneration outcomes. Specifically, we explored the role of Wnt signaling inhibition on PNS regeneration by delivering Wnt inhibitors, sFRP2 and WIF1, after sciatic nerve transection and sciatic nerve crush injuries. Our results demonstrate that WIF1 promoted nerve regeneration (p < 0.05) after sciatic nerve crush injury. More importantly, we revealed the therapeutic window for the treatment of Wnt inhibitors, which is 1 week post sciatic nerve crush when the non-canonical receptor tyrosine kinase (Ryk) is significantly upregulated.

Local delivery strategies to restore immune homeostasis in the context of inflammation

Immune homeostasis is maintained by a precise balance between effector immune cells and regulatory immune cells. Chronic deviations from immune homeostasis, driven by a greater ratio of effector to regulatory cues, can promote the development and propagation of inflammatory diseases/conditions (i.e., autoimmune diseases, transplant rejection, etc.). Current methods to treat chronic inflammation rely upon systemic administration of non-specific small molecules, resulting in broad immunosuppression with unwanted side effects. Consequently, recent studies have developed more localized and specific immunomodulatory approaches to treat inflammation through the use of local biomaterial-based delivery systems. In particular, this review focuses on (1) local biomaterial-based delivery systems, (2) common materials used for polymeric-delivery systems and (3) emerging immunomodulatory trends used to treat inflammation with increased specificity.

Preclinical evaluation of methotrexate-loaded polyelectrolyte complexes and thermosensitive hydrogels as treatment for rheumatoid arthritis

This work proposes new methotrexate (MTX) loaded drug delivery systems (DDS) to treat rheumatoid arthritis via the intra-articular route: a poloxamer based thermosensitive hydrogel (MTX-HG), oligochitosan and hypromellose phthalate-based polyelectrolyte complexes (MTX-PEC) and their association (MTX-PEC-HG). MTX-PEC showed 470 ± 166 nm particle size, 0.298 ± 0.108 polydispersity index, +26 ± 2 mV and 74.3 ± 5.8% MTX efficiency entrapment and particle formation was confirmed by infrared spectroscopy and thermal analysis. MTX-HG and MTX-PEC-HG gelled at 36.7°C. MTX drug release profile was prolonged for MTX-HG and MTX-PEC-HG, and faster for MTX-PEC and free MTX. The in vivo effect of the MTX-DDSs systems was evaluated in induced arthritis rats as single intra-articular dose. The assessed parameters were the mechanical nociceptive threshold, the plasmatic IL-1β level and histological analysis of the tibiofemoral joint. MTX-HG and MTX-PEC-HG performance were similar to free MTX and worse than oral MTX, used as positive control. All DDSs showed some irritative effect, for which further studies are required. MTX-PEC was the best treatment on recovering cartilage damage and decreasing allodynia. Thus, MTX-PEC demonstrated potential to treat rheumatoid arthritis, with the possibility of decreasing the systemic exposure to the drug.

Tumor necrosis factor-α small interfering RNA alveolar epithelial cell-targeting nanoparticles reduce lung injury in C57BL/6J mice with sepsis

Background

The role of tumor necrosis factor (TNF)-α small interfering (si)RNA alveolar epithelial cell (AEC)-targeting nanoparticles in lung injury is unclear.

Methods

Sixty C57BL/6J mice with sepsis were divided into normal, control, sham, 25 mg/kg, 50 mg/kg, and 100 mg/kg siRNA AEC-targeting nanoparticles groups (n = 10 per group). The wet:dry lung weight ratio, and hematoxylin and eosin staining, western blotting, and enzyme-linked immunosorbent assays for inflammatory factors were conducted to compare differences among groups.

Results

The wet:dry ratio was significantly lower in control and sham groups than other groups. TNF-α siRNA AEC-targeting nanoparticles significantly reduced the number of eosinophils, with significantly lower numbers in the 50 mg/kg group than in 25 mg/kg and 100 mg/kg groups. The nanoparticles also significantly reduced the expression of TNF-α, B-cell lymphoma-2, caspase 3, interleukin (IL)-1β, and IL-6, with TNF-α expression being significantly lower in the 50 mg/kg group than in 25 mg/kg and 100 mg/kg groups.

Conclusion

TNF-α siRNA AEC-targeting nanoparticles appear to be effective at improving lung injury-related sepsis, and 50 mg/kg may be a preferred dose option for administration.

Hydrogel microspheres for spatiotemporally controlled delivery of RNA and silencing gene expression within scaffold-free tissue engineered constructs

Delivery systems for controlled release of RNA interference (RNAi) molecules, including small interfering (siRNA) and microRNA (miRNA), have the potential to direct stem cell differentiation for regenerative musculoskeletal applications. To date, localized RNA delivery platforms in this area have focused predominantly on bulk scaffold-based approaches, which can interfere with cell-cell interactions important for recapitulating some native musculoskeletal developmental and healing processes in tissue regeneration strategies. In contrast, scaffold-free, high density human mesenchymal stem cell (hMSC) aggregates may provide an avenue for creating a more biomimetic microenvironment. Here, photocrosslinkable dextran microspheres (MS) encapsulating siRNA-micelles were prepared via an aqueous emulsion method and incorporated within hMSC aggregates for localized and sustained delivery of bioactive siRNA. siRNA-micelles released from MS in a sustained fashion over the course of 28 days, and the released siRNA retained its ability to transfect cells for gene silencing. Incorporation of fluorescently labeled siRNA (siGLO)-laden MS within hMSC aggregates exhibited tunable siGLO delivery and uptake by stem cells. Incorporation of MS loaded with siRNA targeting green fluorescent protein (siGFP) within GFP-hMSC aggregates provided sustained presentation of siGFP within the constructs and prolonged GFP silencing for up to 15 days. This platform system enables sustained gene silencing within stem cell aggregates and thus shows great potential in tissue regeneration applications. STATEMENT OF SIGNIFICANCE: This work presents a new strategy to deliver RNA-nanocomplexes from photocrosslinked dextran microspheres for tunable presentation of bioactive RNA. These microspheres were embedded within scaffold-free, human mesenchymal stem cell (hMSC) aggregates for sustained gene silencing within three-dimensional cell constructs while maintaining cell viability. Unlike exogenous delivery of RNA within culture medium that suffers from diffusion limitations and potential need for repeated transfections, this strategy provides local and sustained RNA presentation from the microspheres to cells in the constructs. This system has the potential to inhibit translation of hMSC differentiation antagonists and drive hMSC differentiation toward desired specific lineages, and is an important step in the engineering of high-density stem cell systems with incorporated instructive genetic cues for application in tissue regeneration.

RNA interfering molecule delivery from in situ forming biodegradable hydrogels for enhancement of bone formation in rat calvarial bone defects

RNA interference (RNAi) may be an effective and valuable tool for promoting the growth of functional tissue, as short interfering RNA (siRNA) and microRNA (miRNA) can block the expression of genes that have negative effects on tissue regeneration. Our group has recently reported that the localized and sustained presentation of siRNA against noggin (siNoggin) and miRNA-20a from in situ forming poly(ethylene glycol) (PEG) hydrogels enhanced osteogenic differentiation of encapsulated human bone marrow-derived mesenchymal stem cells (hMSCs). Here, the capacity of the hydrogel system to accelerate bone formation in a rat calvarial bone defect model is presented. After 12 weeks post-implantation, the hydrogels containing encapsulated hMSCs and miRNA-20a resulted in more bone formation in the defects than the hydrogels containing hMSCs without siRNA or with negative control siRNA. This localized and sustained RNA interfering molecule delivery system may provide an excellent platform for healing bony defects and other tissues.

STATEMENT OF SIGNIFICANCE

Delivery of RNAi molecules may be a valuable strategy to guide cell behavior for tissue engineering applications, but to date there have been no reports of a biomaterial system capable of both encapsulation of cells and controlled delivery of incorporated RNA. Here, we present PEG hydrogels that form in situ via Michael type reaction, and that permit encapsulation of hMSCs and the concomitant controlled delivery of siNoggin and/or miRNA-20a. These RNAs were chosen to suppress noggin, a BMP-2 antagonist, and/or PPAR-γ, a negative regulator of BMP-2-mediated osteogenesis, and therefore promote osteogenic differentiation of hMSCs and subsequent bone repair in critical-sized rat calvarial defects. Simultaneous delivery of hMSCs and miRNA-20a enhanced repair of these defects compared to hydrogels containing hMSCs without siRNA or with negative control siRNA. This in situ forming PEG hydrogel system offers an exciting platform for healing critical-sized bone defects by localized, controlled delivery of RNAi molecules to encapsulated hMSCs and surrounding cells.

Lipid nanoparticles with minimum burst release of TNF-α siRNA show strong activity against rheumatoid arthritis unresponsive to methotrexate

TNF-α siRNA has shown promising therapeutic benefits in animal models of rheumatoid arthritis. However, there continues to be a need for siRNA delivery systems that have high siRNA encapsulation efficiency and minimum burst release of TNF-α siRNA, and can target inflamed tissues after intravenous administration. Herein we report a novel acid-sensitive sheddable PEGylated solid-lipid nanoparticle formulation of TNF-α-siRNA, AS-TNF-α-siRNA-SLNs, prepared by incorporating lipophilized TNF-α-siRNA into solid-lipid nanoparticles composed of biocompatible lipids such as lecithin and cholesterol. The nanoparticles are approximately 120 nm in diameter, have a high siRNA encapsulation efficiency (>90%) and a minimum burst release of siRNA (<5%), and increase the deilvery of the siRNA in chronic inflammation sites in mouse models, including in a mouse model with collagen-induced arthritis. Importantly, in a mouse model of collagen antibody-induced arthritis that does not respond to methotrexate therapy, intravenous injection of the AS-TNF-α-siRNA-SLNs significantly reduced paw thickness, bone loss, and histopathological scores. These findings highlight the potential of using this novel siRNA nanoparticle formulation to effectively treat arthritis, potentially in patients who do not respond adequately to methotrexate.

Therapeutic approaches for the delivery of TNF-α siRNA

Immune-mediated diseases are emerging as a major healthcare concern in the present era. TNF-α, a proinflammatory cytokine, plays a major role in the manifestation of these diseases by mediating different pathways and inducing the expression of other cytokines. In last decades, monoclonal antibodies and extracellular portion of human TNF-α receptors are explored in this area; however, the risk of immunological response and undesired effects urge a need to develop more effective therapies to control TNF-α levels. siRNA therapeutic strategies are emerging for the treatment of myriad of diseases, but the delivery challenges associated with siRNA require the development of suitable delivery vectors. For delivery of TNF-α siRNA, both viral and nonviral vectors are explored. This review attempts to describe different delivery approaches for TNF-α siRNA with special focus on nonviral delivery vectors.

Single intra-articular injection of fluvastatin-PLGA microspheres reduces cartilage degradation in rabbits with experimental osteoarthritis

Statins are cholesterol-lowering drugs that inhibit 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, a rate-limiting enzyme of the mevalonate pathway. The anti-inflammatory effect of statins has been reported in recent years. The present study investigated therapeutic effects of the local administration of statin in osteoarthritis (OA). We assessed clinically used statins and selected fluvastatin for further experimentation, as it showed potent anabolic and anti-catabolic effects on human OA chondrocytes. To achieve controlled intra-articular administration of statin, we developed an intra-articular injectable statin using poly(lactic-co-glycolic acid) (PLGA) as a drug delivery system (DDS). The release profile of the statin was evaluated in vitro. Finally, therapeutic effects of fluvastatin-loaded PLGA microspheres (FLU-PLGA) were tested in a rabbit OA model. Rabbit knees were divided into four subgroups: group 1-A, PLGA-treated group; group 1-B, PLGA contralateral saline control group; group 2-A, FLU-PLGA-treated group; and group 2-B, FLU-PLGA contralateral saline control group. Histological analysis 5 weeks after intra-articular injection revealed that OARSI scores were lower in group 2-A. No significant differences in OARSI scores were observed between groups 1-A, 1-B, and 2-B. This study indicates that a single intra-articular injection of fluvastatin-loaded PLGA microspheres could be a novel therapeutic approach for treating patients with OA. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2465-2475, 2017.

Effects of Inflammation on Multiscale Biomechanical Properties of Cartilaginous Cells and Tissues

Cells within cartilaginous tissues are mechanosensitive and thus require mechanical loading for regulation of tissue homeostasis and metabolism. Mechanical loading plays critical roles in cell differentiation, proliferation, biosynthesis, and homeostasis. Inflammation is an important event occurring during multiple processes, such as aging, injury, and disease. Inflammation has significant effects on biological processes as well as mechanical function of cells and tissues. These effects are highly dependent on cell/tissue type, timing, and magnitude. In this review, we summarize key findings pertaining to effects of inflammation on multiscale mechanical properties at subcellular, cellular, and tissue level in cartilaginous tissues, including alterations in mechanotransduction and mechanosensitivity. The emphasis is on articular cartilage and the intervertebral disc, which are impacted by inflammatory insults during degenerative conditions such as osteoarthritis, joint pain, and back pain. To recapitulate the pro-inflammatory cascades that occur in vivo, different inflammatory stimuli have been used for in vitro and in situ studies, including tumor necrosis factor (TNF), various interleukins (IL), and lipopolysaccharide (LPS). Therefore, this review will focus on the effects of these stimuli because they are the best studied pro-inflammatory cytokines in cartilaginous tissues. Understanding the current state of the field of inflammation and cell/tissue biomechanics may potentially identify future directions for novel and translational therapeutics with multiscale biomechanical considerations.

Synthetic nanoscale electrostatic particles as growth factor carriers for cartilage repair

The efficient transport of biological therapeutic materials to target tissues within the body is critical to their efficacy. In cartilage tissue, the lack of blood vessels prevents the entry of systemically administered drugs at therapeutic levels. Within the articulating joint complex, the dense and highly charged extracellular matrix (ECM) hinders the transport of locally administered therapeutic molecules. Consequently, cartilage injury is difficult to treat and frequently results in debilitating osteoarthritis. Here we show a generalizable approach in which the electrostatic assembly of synthetic polypeptides and a protein, insulin‐like growth factor‐1 (IGF‐1), can be used as an early interventional therapy to treat injury to the cartilage. We demonstrated that poly(glutamic acid) and poly(arginine) associated with the IGF‐1 via electrostatic interactions, forming a net charged nanoscale polyelectrolyte complex (nanoplex). We observed that the nanoplex diffused into cartilage plugs in vitro and stimulated ECM production. In vivo, we monitored the transport, retention and therapeutic efficacy of the nanoplex in an established rat model of cartilage injury. A single therapeutic dose, when administered within 48 hr of the injury, conferred protection against cartilage degradation and controlled interleukin‐1 mediated inflammation. IGF‐1 contained in the nanoplex was detected in the joint space for up to 4 weeks following administration and retained bioactivity. The results indicate the potential of this approach as an early intervention therapy following joint injury to delay or even entirely prevent the onset of osteoarthritis.

Mannan-Binding Lectin-Associated Serine Protease 1/3 Cleavage of Pro-Factor D into Factor D In Vivo and Attenuation of Collagen Antibody-Induced Arthritis through Their Targeted Inhibition by RNA Interference-Mediated Gene Silencing

The complement system is proposed to play an important role in the pathogenesis of rheumatoid arthritis (RA). The complement system mannan-binding lectin-associated serine proteases (MASP)-1/3 cleave pro-factor D (proDf; inactive) into Df (active), but it is unknown where this cleavage occurs and whether inhibition of MASP-1/3 is a relevant therapeutic strategy for RA. In the present study, we show that the cleavage of proDf into Df by MASP-1/3 can occur in the circulation and that inhibition of MASP-1/3 by gene silencing is sufficient to ameliorate collagen Ab-induced arthritis in mice. Specifically, to examine the cleavage of proDf into Df, MASP-1/3-producing Df-/- liver tissue (donor) was transplanted under the kidney capsule of MASP-1/3-/- (recipient) mice. Five weeks after the liver transplantation, cleaved Df was present in the circulation of MASP-1/3-/- mice. To determine the individual effects of MASP-1/3 and Df gene silencing on collagen Ab-induced arthritis, mice were injected with scrambled, MASP-1/3-targeted, or Df-targeted small interfering RNAs (siRNAs). The mRNA levels for MASP-1 and -3 decreased in the liver to 62 and 58%, respectively, in mice injected with MASP-1/3 siRNAs, and Df mRNA decreased to 53% in the adipose tissue of mice injected with Df siRNAs; additionally, circulating MASP-1/3 and Df protein levels were decreased. In mice injected with both siRNAs the clinical disease activity, histopathologic injury scores, C3 deposition, and synovial macrophage/neutrophil infiltration were significantly decreased. Thus, MASP-1/3 represent a new therapeutic target for the treatment of RA, likely through both direct effects on the lectin pathway and indirectly through the alternative pathway.

Intra-articular interleukin-1 receptor antagonist (IL1-ra) microspheres for posttraumatic osteoarthritis: in vitro biological activity and in vivo disease modifying effect

Background

Interleukin-1 receptor antagonist (IL-1 ra) can be disease-modifying in posttraumatic osteoarthritis (PTOA). One limitation is its short joint residence time. We hypothesized that IL-1 ra encapsulation in poly (lactide-co-glycolide) (PLGA) microspheres reduces IL-1 ra systemic absorption and provides an enhanced anti-PTOA effect.

Methods

IL-1 ra release kinetics and biological activity: IL-1 ra encapsulation into PLGA microsphere was performed using double emulsion solvent extraction. Lyophilized PLGA IL-1 ra microspheres were resuspended in PBS and supernatant IL-1 ra concentrations were assayed. The biological activity of IL-1 ra from PLGA IL-1 ra microspheres was performed using IL-1 induced lymphocyte proliferation and bovine articular cartilage degradation assays. Systemic absorption of IL-1 ra following intra-articular (IA) injection of PLGA IL-1 ra or IL-1 ra: At 1, 3, 6, 12 and 24 h following injection of 50 μl PLGA IL-1 ra (n = 6) or IL-1 ra (n = 6), serum samples were collected and IL-1 ra concentrations were determined. Anterior cruciate ligamenttransection (ACLT) and IA dosing: ACLT was performed in 8–10 week old male Lewis rats (n = 42). PBS (50 μl; n = 9), IL-1 ra (50 μl; 5 mg/ml; n = 13), PLGA IL-1 ra (50 μl; equivalent to 5 mg/ml IL-1 ra; n = 14) or PLGA particles (50 μl; n = 6) treatments were performed on days 7, 14, 21 and 28 following ACLT. Cartilage and synovial histopathology: On day 35, animal ACLT joints were harvested and tibial cartilage and synovial histopathology scoring was performed.

Results

Percent IL-1 ra content in the supernatant at 6 h was 13.44 ± 9.27 % compared to 34.16 ± 12.04 %, 47.89 ± 12.71 %, 57.14 ± 11.71 %, and 93.90 ± 8.50 % at 12, 24, 48 and 72 h, respectively. PLGA IL-1 ra inhibited lymphocyte proliferation and cartilage degradation similar to IL-1 ra. Serum IL-1 ra levels were significantly lower at 1, 3, and 6 h following PLGA IL-1 ra injection compared to IL-1 ra. Cartilage and synovial histopathology scores were significantly lower in the PLGA IL-1 ra group compared to PBS and PLGA groups (p < 0.001).

Conclusions

IL-1 ra encapsulation in PLGA microspheres is feasible with no alteration to IL-1 ra biological activity. PLGA IL-1 ra exhibited an enhanced disease-modifying effect in a PTOA model compared to similarly dosed IL-1 ra.

Acid-Sensitive Sheddable PEGylated PLGA Nanoparticles Increase the Delivery of TNF-α siRNA in Chronic Inflammation Sites

There has been growing interest in utilizing small interfering RNA (siRNA) specific to pro-inflammatory cytokines, such as tumor necrosis factor-α ( TNF-α), in chronic inflammation therapy. However, delivery systems that can increase the distribution of the siRNA in chronic inflammation sites after intravenous administration are needed. Herein we report that innovative functionalization of the surface of siRNA-incorporated poly (lactic-co-glycolic) acid (PLGA) nanoparticles significantly increases the delivery of the siRNA in the chronic inflammation sites in a mouse model. The TNF-α siRNA incorporated PLGA nanoparticles were prepared by the standard double emulsion method, but using stearoyl-hydrazone-polyethylene glycol 2000, a unique acid-sensitive surface active agent, as the emulsifying agent, which renders (i) the nanoparticles PEGylated and (ii) the PEGylation sheddable in low pH environment such as that in chronic inflammation sites. In a mouse model of lipopolysaccharide-induced chronic inflammation, the acid-sensitive sheddable PEGylated PLGA nanoparticles showed significantly higher accumulation or distribution in chronic inflammation sites than PLGA nanoparticles prepared with an acid-insensitive emulsifying agent (i.e., stearoyl-amide-polyethylene glycol 2000) and significantly increased the distribution of the TNF-α siRNA incorporated into the nanoparticles in inflamed mouse foot.

Cellular uptake and fate of fibroin microspheres loaded with randomly fragmented DNA in 3T3 cells

Purified fibroin protein can be obtained in large quantities from silk fibers and processed to form microscopic particles as delivery vehicles for therapeutic agents. In this study, we demonstrated that fibroin microspheres were taken up by 3T3 cells, localized in the nonlysosomal compartment, and secreted from the cytoplasm after medium replenishment. DNA-loaded microspheres were taken up by >95% of 3T3 cells. DNA cargo had no influence on the intracellular trafficking of microspheres, while fluorescently labeled cargo DNA was observed in the lysosomal compartment and in the microspheres. These results indicate that fibroin microspheres can travel through 3T3 cells without making any contact with the lysosomal compartments. The amount of DNA loaded in the microspheres taken up by 3T3 cells was estimated up to 831.0 pg/cell. Thus, fibroin microspheres can deliver a large amount of randomly fragmented DNA (<10 kb) into the cytoplasmic compartment of 3T3 cells.

Particle-based technologies for osteoarthritis detection and therapy

Osteoarthritis (OA) is a disease characterized by degradation of joints with the development of painful osteophytes in the surrounding tissues. Currently, there are a limited number of treatments for this disease, and many of these only provide temporary, palliative relief. In this review, we discuss particle-based drug delivery systems that can provide targeted and sustained delivery of imaging and therapeutic agents to OA-affected sites. We focus on technologies such as polymeric micelles and nano-/microparticles, liposomes, and dendrimers for their potential treatment and/or diagnosis of OA. Several promising studies are highlighted, motivating the continued development of delivery technologies to improve treatments for OA.

PLGA microspheres encapsulating siRNA

The therapeutic use of small interfering RNA (siRNA) represents a new and powerful approach to suppress the expression of pathologically genes. However, biopharmaceutical drawbacks, such as short half-life, poor cellular uptake, and unspecific distribution into the body, hamper the development of siRNA-based therapeutics. Poly(lactide-co-glycolide), (PLGA) microspheres can be a useful tool to overcome these issues. siRNA can be encapsulated into the PLGA microspheres, which protects the loaded nucleic acid against the enzymatic degradation. Moreover, PLGA microspheres can be injected directly into the action site, where the siRNA can be released in controlled manner, thus avoiding the need of frequent invasive administrations. The complete biodegradability of PLGA to monomers easily metabolized by the body, and its approval by FDA and EMA for parenteral administration, assure the safety of this copolymer and do not require the removal of the device after the complete drug release. In chapter, a basic protocol for the preparation of PLGA microspheres encapsulating siRNA is described. This protocol is based on a double emulsion/solvent evaporation technique, a well known and easy to reproduce method. This specific protocol has been developed to encapsulate a siRNA anti-TNFα in PLGA microspheres, and it has been designed and optimized to achieve high siRNA encapsulation efficiency and slow siRNA release in vitro. However, it can be extended also to other siRNA as well as other RNA or DNA-based oligonucleotides (miRNA, antisense, decoy, etc.). Depending on the applications, chemical modifications of the backbone and site-specific modification within the siRNA sequences could be required.

Biomaterial-mediated modification of the local inflammatory environment

Inflammation plays a major role in the rejection of biomaterial implants. In addition, despite playing an important role in the early stages of wound healing, dysregulated inflammation has a negative impact on the wound healing processes. Thus, strategies to modulate excessive inflammation are needed. Through the use of biomaterials to control the release of anti-inflammatory therapeutics, increased control over inflammation is possible in a range of pathological conditions. However, the choice of biomaterial (natural or synthetic), and the form it takes (solid, hydrogel, or micro/nanoparticle) is dependent on both the cause and tissue location of inflammation. These considerations also influence the nature of the anti-inflammatory therapeutic that is incorporated into the biomaterial to be delivered. In this report, the range of biomaterials and anti-inflammatory therapeutics that have been combined will be discussed, as well as the functional benefit observed. Furthermore, we point toward future strategies in the field that will bring more efficacious anti-inflammatory therapeutics closer to realization.

Co-delivery of doxorubicin and siRNA for glioma therapy by a brain targeting system: angiopep-2-modified poly(lactic-co-glycolic acid) nanoparticles

It is very challenging to treat brain cancer because of the blood-brain barrier (BBB) restricting therapeutic drug or gene to access the brain. In this research project, angiopep-2 (ANG) was used as a brain-targeted peptide for preparing multifunctional ANG-modified poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs), which encapsulated both doxorubicin (DOX) and epidermal growth factor receptor (EGFR) siRNA, designated as ANG/PLGA/DOX/siRNA. This system could efficiently deliver DOX and siRNA into U87MG cells leading to significant cell inhibition, apoptosis and EGFR silencing in vitro. It demonstrated that this drug system was capable of penetrating the BBB in vivo, resulting in more drugs accumulation in the brain. The animal study using the brain orthotopic U87MG glioma xenograft model indicated that the ANG-targeted co-delivery of DOX and EGFR siRNA resulted in not only the prolongation of the life span of the glioma-bearing mice but also an obvious cell apoptosis in glioma tissue.

Progress in intra-articular therapy

Diarthrodial joints are well suited to intra-articular injection, and the local delivery of therapeutics in this fashion brings several potential advantages to the treatment of a wide range of arthropathies. Possible benefits over systemic delivery include increased bioavailability, reduced systemic exposure, fewer adverse events, and lower total drug costs. Nevertheless, intra-articular therapy is challenging because of the rapid egress of injected materials from the joint space; this elimination is true of both small molecules, which exit via synovial capillaries, and of macromolecules, which are cleared by the lymphatic system. In general, soluble materials have an intra-articular dwell time measured only in hours. Corticosteroids and hyaluronate preparations constitute the mainstay of FDA-approved intra-articular therapeutics. Recombinant proteins, autologous blood products and analgesics have also found clinical use via intra-articular delivery. Several alternative approaches, such as local delivery of cell and gene therapy, as well as the use of microparticles, liposomes, and modified drugs, are in various stages of preclinical development.

MHC universal cells survive in an allogeneic environment after incompatible transplantation

Cell, tissue, and organ transplants are commonly performed for the treatment of different diseases. However, major histocompatibility complex (MHC) diversity often prevents complete donor-recipient matching, resulting in graft rejection. This study evaluates in a preclinical model the capacity of MHC class I-silenced cells to engraft and grow upon allogeneic transplantation. Short hairpin RNA targeting β2-microglobulin (RN_shβ2m) was delivered into fibroblasts derived from LEW/Ztm (RT1^l) (RT1-A^l) rats using a lentiviral-based vector. MHC class I (RT1-A-) expressing and -silenced cells were injected subcutaneously in LEW rats (RT1^l) and MHC-congenic LEW.1W rats (RT1^u), respectively. Cell engraftment and the status of the immune response were monitored for eight weeks after transplantation. In contrast to RT1-A-expressing cells, RT1-A-silenced fibroblasts became engrafted and were still detectable eight weeks after allogeneic transplantation. Plasma levels of proinflammatory cytokines IL-1α, IL-1β, IL-6, TNF-α, and IFN-γ were significantly higher in animals transplanted with RT1-A-expressing cells than in those receiving RT1-A-silenced cells. Furthermore, alloantigen-specific T-cell proliferation rates derived from rats receiving RT1-A-expressing cells were higher than those in rats transplanted with RT1-A-silenced cells. These data suggest that silencing MHC class I expression might overcome the histocompatibility barrier, potentially opening up new avenues in the field of cell transplantation and regenerative medicine.