Cell penetrating recombinant Foxp3 protein enhances Treg function and ameliorates arthritis

mRNA Lipid Nanoparticles for Ex Vivo Engineering of Immunosuppressive T Cells for Autoimmunity Therapies

Cell-based therapies for autoimmune diseases have gained significant traction, with several approaches centered around the regulatory T (Treg) cell─a well-known immunosuppressive cell characterized by its expression of the transcription factor Foxp3. Unfortunately, due to low numbers of Treg cells available in circulation, harvesting and culturing Treg cells remains a challenge. It has been reported that engineering Foxp3 expression in CD4+ T cells can result in a Treg-like phenotype; however, current methods result in the inefficient engineering of these cells. Here, we develop an ionizable lipid nanoparticle (LNP) platform to effectively deliver Foxp3 mRNA to CD4+ T cells. We successfully engineer CD4+ T cells into Foxp3-T (FP3T) cells that transiently exhibit an immunosuppressive phenotype and functionally suppress the proliferation of effector T cells. These results demonstrate the promise of an LNP platform for engineering immunosuppressive T cells with potential applications in autoimmunity therapies.

Delivery of transcription factors as modulators of cell differentiation

Fundamental studies performed during the last decades have shown that cell fate is much more plastic than previously considered, and technologies for its manipulation are a keystone for many new tissue regeneration therapies. Transcription factors (TFs) are DNA-binding proteins that control gene expression, and they have critical roles in the control of cell fate and other cellular behavior. TF-based therapies have much medical potential, but their use as drugs depends on the development of suitable delivery technologies that can help them reach their action site inside of the cells. TFs can be used either as proteins or encoded in polynucleotides. When used in protein form, many TFs require to be associated to a cell-penetrating peptide or another transduction domain. As polynucleotides, they can be delivered either by viral carriers or by non-viral systems such as polyplexes and lipoplexes. TF-based therapies have extensively shown their potential to solve many tissue-engineering problems, including bone, cartilage and cardiac regeneration. Yet, their use has expanded beyond regenerative medicine to other prominent disease areas such as cancer therapy and immunomodulation. This review summarizes some of the delivery options for effective TF-based therapies and their current main applications.

Single-Stranded DNA Aptamers Against TNF and Their Potential Applications

Aptamers are short, single-stranded RNA or DNA sequences, which can bind to protein ligands with high affinity and specificity. Applications of aptamers are broad, ranging from drugs and drug delivery vehicles to biosensors. Tumor necrosis factor (TNF) is an inflammatory cytokine that plays a critical role in the pathogenesis of several autoimmune inflammatory diseases. Blocking TNF activity by monoclonal antibodies or TNF receptor fusion protein has been tremendously successful in treating these diseases. However, manufacturing these biological TNF inhibitors is expensive and a significant proportion of patients do not respond to TNF blockade. Here we describe selection of single-stranded DNA aptamers for TNF blockage, and their bioactivity in blocking TNF-mediated cytotoxicity in vitro. These TNF-binding aptamers have the potential to serve as alternatives to biological TNF inhibitors and to be used as in vivo probes for TNF detection.

Self-Transducible Bimodal PDX1-FOXP3 Protein Lifts Insulin Secretion and Curbs Autoimmunity, Boosting Tregs in Type 1 Diabetic Mice

Type 1 diabetes (T1D) is characterized by massive destruction of insulin-producing β cells by autoreactive T lymphocytes, arising via defective immune tolerance. Therefore, effective anti-T1D therapeutics should combine autoimmunity-preventing and insulin production-restoring properties. We constructed a cell-permeable PDX1-FOXP3-TAT fusion protein (FP) composed of two transcription factors: forkhead box P3 (FOXP3), the master regulator of differentiation and functioning of self-tolerance-promoting Tregs, and pancreatic duodenal homeobox-1 (PDX1), the crucial factor supporting β cell development and maintenance. The FP was tested in vitro and in a non-obese diabetic mouse T1D model. In vitro, FP converted naive CD4⁺ T cells into a functional "Treg-like" subset, which suppressed cytokine secretion, downregulated antigen-specific responses, and curbed viability of diabetogenic effector cells. In hepatic stem-like cells, FP potentiated endocrine transdifferentiation, inducing expression of Insulin2 and other β lineage-specific genes. In vivo, FP administration to chronically diabetic mice triggered (1) a significant elevation of insulin and C-peptide levels, (2) the formation of insulin-containing cell clusters in livers, and (3) a systemic anti-inflammatory shift (higher Foxp3⁺CD4⁺CD25⁺ T cell frequencies, elevated rates of IL-10-producing cells, and reduced rates of IFN-γ-secreting cells). Overall, in accordance with its design, PDX1-FOXP3-TAT FP delivered both Treg-stabilizing anti-autoimmune and de novo insulin-producing effects, proving its anti-T1D therapeutic potential.

Regeneration of hyaline-like cartilage in situ with SOX9 stimulation of bone marrow-derived mesenchymal stem cells

Microfracture, a common procedure for treatment of cartilage injury, induces fibrocartilage repair by recruiting bone marrow derived mesenchymal stem cells (MSC) to the site of cartilage injury. However, fibrocartilage is inferior biomechanically to hyaline cartilage. SRY-type high-mobility group box-9 (SOX9) is a master regulator of chondrogenesis by promoting proliferation and differentiation of MSC into chondrocytes. In this study we aimed to test the therapeutic potential of cell penetrating recombinant SOX9 protein in regeneration of hyaline cartilage in situ at the site of cartilage injury. We generated a recombinant SOX9 protein which was fused with super positively charged green fluorescence protein (GFP) (scSOX9) to facilitate cell penetration. scSOX9 was able to induce chondrogenesis of bone marrow derived MSC in vitro. In a rabbit cartilage injury model, scSOX9 in combination with microfracture significantly improved quality of repaired cartilage as shown by macroscopic appearance. Histological analysis revealed that the reparative tissue induced by microfracture with scSOX9 had features of hyaline cartilage; and collagen type II to type I ratio was similar to that in normal cartilage. This short term in vivo study demonstrated that when administered at the site of microfracture, scSOX9 was able to induce reparative tissue with features of hyaline cartilage.

Construction of a tissue-specific transcription factor-tethered extracellular matrix protein via coiled-coil helix formation

Tissue-specific transcription factor Olig2 was tethered to a designed artificial extracellular matrix proteinviacoiled-coil helix formation.

Cell-penetrable mouse forkhead box protein 3 alleviates experimental arthritis in mice by up-regulating regulatory T cells

Regulatory T cells (T(regs)) have potential applications in clinical disease therapy, such as autoimmune diseases and transplant rejection. However, their numbers are limited. Forkhead box protein 3 (FoxP3) is a key transcription factor that controls T(reg) development and function. Here, we generated a cell-permeable fusion protein, protein transduction domain (PTD)-conjugated mouse FoxP3 protein (PTD-mFoxP3), and evaluated whether PTD-mFoxp3 can alleviate rheumatoid arthritis (RA) in the collagen-induced arthritis (CIA) mouse model. As expected, PTD-mFoxP3 was transduced into cells effectively, and inhibited T cell activation and attenuated the cell proliferation. It decreased interleukin (IL) 2 and interferon (IFN)-γ expression, and increased IL-10 expression in activated CD4(+)CD25(-) T cells. PTD-mFoxP3-transduced CD4(+)CD25(-) T cells attenuated proliferation of activated CD4(+)CD25(-) T cells. In addition, PTD-mFoxP3 blocked the Th17 differentiation programme in vitro and down-regulated IL-17 production from T cells by modulating induction and levels of retinoid-related orphan receptor gamma t (RORγt). Intra-articular delivery of PTD-mFoxP3 delayed disease incidence remarkably and alleviated autoimmune symptoms of CIA mice. Moreover, protective effects of PTD-mFoxP3 were associated with regulating the balance of T helper type 17 (Th17) and T(regs). These results suggest that PTD-mFoxP3 may be a candidate for RA therapy.