Prevention and treatment of autoimmune diseases with plant virus nanoparticles.

Plant viruses are natural, self-assembling nanostructures with versatile and genetically programmable shells, making them useful in diverse applications ranging from the development of new materials to diagnostics and therapeutics. Here, we describe the design and synthesis of plant virus nanoparticles displaying peptides associated with two different autoimmune diseases. Using animal models, we show that the recombinant nanoparticles can prevent autoimmune diabetes and ameliorate rheumatoid arthritis. In both cases, this effect is based on a strictly peptide-related mechanism in which the virus nanoparticle acts both as a peptide scaffold and as an adjuvant, showing an overlapping mechanism of action. This successful preclinical testing could pave the way for the development of plant viruses for the clinical treatment of human autoimmune diseases.

Effects of Weekly Supplementation of Cholecalciferol and Calcifediol Among the Oldest-Old People: Findings From a Randomized Pragmatic Clinical Trial.

Vitamin D inadequacy is pervasive in the oldest-old. Many vitamin D metabolites are available for supplementation, their effects on the recovery of adequate serum levels remain unknown. We investigate the effects of supplementation with cholecalciferol (D3) and calcifediol (25D3) on serum levels of 25(OH)D, 1-25(OH)D, bone and inflammatory markers, ultimately identifying clinical predictors of successful treatment. Sixty-seven oldest-old individuals were randomized to weekly administration of 150 mcg of 25D3 or D3, from hospital admission to 7 months after discharge. Supplementation of 25D3 and D3 were associated with increasing serum levels of 25(OH)D (p < 0.001) and 1-25(OH)D (p = 0.01). Participants on 25D3 experienced a steeper rise than those on D3 (group*time interaction p = 0.01), after adjustment for intact parathyroid hormone (iPTH) levels the differences disappeared (intervention*iPTH interaction p = 0.04). Vitamin D supplementation was associated with a decreasing trend of iPTH and C-reactive protein (CRP) (p < 0.001). Polypharmacy and low handgrip strength were predictors of failure of intervention, independent of vitamin D metabolites. In conclusion, D3 and 25D3 supplementation significantly increase vitamin D serum levels in the oldest-old individuals, with a tendency of 25D3 to show a faster recovery of acceptable iPTH levels than D3. Polypharmacy and low muscle strength weaken the recovery of adequate vitamin D serum levels.

Enhanced GAD65 production in plants using the MagnICON transient expression system: Optimization of upstream production and downstream processing.

Plants have emerged as competitive production platforms for pharmaceutical proteins that are required in large quantities. One example is the 65-kDa isoform of human glutamic acid decarboxylase (GAD65), a major autoimmune diabetes autoantigen that has been developed as a vaccine candidate for the primary prevention of diabetes. The expression of GAD65 in plants has been optimized but large-scale purification is hampered by its tendency to associate with membranes. We investigated the potential for large-scale downstream processing by evaluating different combinations of plant-based expression systems and engineered forms of GAD65 in terms of yield, subcellular localization and solubility in detergent-free buffer. We found that a modified version of GAD65 lacking the first 87 amino acids accumulates to high levels in the cytosol and can be extracted in detergent-free buffer. The highest yields of this variant protein were achieved using the MagnICON transient expression system. This combination of truncated GAD65 and the MagnICON system dramatically boosts the production of the recombinant protein and helps to optimize downstream processing for the establishment of a sustainable plant-based production platform for an autoimmune diabetes vaccine candidate.

A comparative analysis of recombinant protein expression in different biofactories: bacteria, insect cells and plant systems.

Plant-based systems are considered a valuable platform for the production of recombinant proteins as a result of their well-documented potential for the flexible, low-cost production of high-quality, bioactive products. In this study, we compared the expression of a target human recombinant protein in traditional fermenter-based cell cultures (bacterial and insect) with plant-based expression systems, both transient and stable. For each platform, we described the set-up, optimization and length of the production process, the final product quality and the yields and we evaluated provisional production costs, specific for the selected target recombinant protein. Overall, our results indicate that bacteria are unsuitable for the production of the target protein due to its accumulation within insoluble inclusion bodies. On the other hand, plant-based systems are versatile platforms that allow the production of the selected protein at lower-costs than Baculovirus/insect cell system. In particular, stable transgenic lines displayed the highest-yield of the final product and transient expressing plants the fastest process development. However, not all recombinant proteins may benefit from plant-based systems but the best production platform should be determined empirically with a case-by-case approach, as described here.

Comparative analysis of different biofactories for the production of a major diabetes autoantigen.

The 65-kDa isoform of human glutamic acid decarboxylase (hGAD65) is a major diabetes autoantigen that can be used for the diagnosis and (more recently) the treatment of autoimmune diabetes. We previously reported that a catalytically-inactive version (hGAD65mut) accumulated to tenfold higher levels than its active counterpart in transgenic tobacco plants, providing a safe and less expensive source of the protein compared to mammalian production platforms. Here we show that hGAD65mut is also produced at higher levels than hGAD65 by transient expression in Nicotiana benthamiana (using either the pK7WG2 or MagnICON vectors), in insect cells using baculovirus vectors, and in bacterial cells using an inducible-expression system, although the latter system is unsuitable because hGAD65mut accumulates within inclusion bodies. The most productive of these platforms was the MagnICON system, which achieved yields of 78.8 µg/g fresh leaf weight (FLW) but this was substantially less than the best-performing elite transgenic tobacco plants, which reached 114.3 µg/g FLW after six generations of self-crossing. The transgenic system was found to be the most productive and cost-effective although the breeding process took 3 years to complete. The MagnICON system was less productive overall, but generated large amounts of protein in a few days. Both plant-based systems were therefore advantageous over the baculovirus-based production platform in our hands.

Progressive decline of residual follicle pool after clinical diagnosis of autoimmune ovarian insufficiency.

CONTEXT: In approximately 5-8% patients with primary ovarian insufficiency (POI), the disease is caused by an autoimmune process made evident by the appearance of autoantibodies against steroidogenic enzymes (SCA-POI). Anti-müllerian hormone (AMH) is the best marker of the residual follicular pool. OBJECTIVE: To evaluate the rate of loss of the residual follicle pool in women with SCA-POI after clinical diagnosis. DESIGN AND METHODS: One hundred and thirty-two women with POI were tested for 21-hydroxylase autoantibodies, 17α-hydroxylase autoantibodies and P450scc autoantibodies, and 35 patients with SCA-POI were identified. AMH was analysed at the time of the first visit in all women with POI, and in follow-up, serum samples were taken 1-3 years after in 11 women with SCA-POI and detectable AMH. RESULTS: 12/35 (35%) women with SCA-POI had AMH levels within the normal range at the time of first sampling, as compared to 6/97 (6%) with idiopathic POI (P < 0·001). 11/17 (65%) women with SCA-POI with <6 years disease duration had normal serum AMH concentration. A progressive decline in AMH concentration was observed at longitudinal follow-up in all 11 AMH-positive women with SCA-POI, at an estimated average rate of 1·6 µg/l AMH/year (corresponding to an average 57% of preserved follicle pool/previous year) (R(2)  = 0·219, P = 0·028). After 6 years of disease duration, only 1/18 (6%) women with SCA-POI had detectable levels of AMH, similar to women with idiopathic POI (5/78, 6%). CONCLUSION: Most women with SCA-POI present at clinical diagnosis with a preserved follicle pool that is progressively lost within a few years.

Non-food/feed seeds as biofactories for the high-yield production of recombinant pharmaceuticals.

We describe an attractive cloning system for the seed-specific expression of recombinant proteins using three non-food/feed crops. A vector designed for direct subcloning by Gateway® recombination was developed and tested in Arabidopsis, tobacco and petunia plants for the production of a chimeric form (GAD67/65) of the 65 kDa isoform of glutamic acid decarboxylase (GAD65). GAD65 is one of the major human autoantigens involved in type 1 diabetes (T1D). The murine anti-inflammatory cytokine interleukin-10 (IL-10) was expressed with the described system in Arabidopsis and tobacco, whereas proinsulin, another T1D major autoantigen, was expressed in Arabidopsis. The cost-effective production of these proteins in plants could allow the development of T1D prevention strategies based on the induction of immunological tolerance. The best yields were achieved in Arabidopsis seeds, where GAD67/65 reached 7.7% of total soluble protein (TSP), the highest levels ever reported for this protein in plants. IL-10 and proinsulin reached 0.70% and 0.007% of TSP, respectively, consistent with levels previously reported in other plants or tissues. This versatile cloning vector could be suitable for the high-throughput evaluation of expression levels and stability of many valuable and difficult to produce proteins.

Recombinant human GAD65 accumulates to high levels in transgenic tobacco plants when expressed as an enzymatically inactive mutant.

The 65-kDa isoform of glutamic acid decarboxylase (GAD65) is the major autoantigen implicated in the development of type 1 diabetes mellitus (T1DM). The bulk manufacture of GAD65 is a potential issue in the fight against T1DM but current production platforms are expensive. We show that a catalytically inactive form of GAD65 (GAD65mut) accumulates at up to 2.2% total soluble protein in transgenic tobacco leaves, which is more than 10-fold the levels achieved with active GAD65, yet the protein retains the immunogenic properties required to treat T1DM. This higher yield was found to be a result of a higher rate of protein synthesis and not transcript availability or protein stability. We found that targeting GAD65 to the endoplasmic reticulum, a strategy that increases the accumulation of many recombinant proteins expressed in plants, did not improve production of GAD65mut. The production of a catalytically inactive autoantigen that retains its immunogenic properties could be a useful strategy to provide high-quality therapeutic protein for treatment of autoimmune T1DM.

Primary ovarian insufficiency due to steroidogenic cell autoimmunity is associated with a preserved pool of functioning follicles.

CONTEXT: Primary ovarian insufficiency (POI) is defined as hypergonadotropic amenorrhea before the age of 40 yr. In 4-5% of patients with POI, an ovarian autoimmune process is present. DESIGN: Serum concentrations of antimüllerian hormone (AMH) have been determined in 26 women with POI due to steroidogenic cell autoimmunity (SCA-POI), 66 with nonautoimmune idiopathic POI (iPOI), 40 postmenopausal women (PMW), and 44 healthy fertile women (HW). SCA-POI was diagnosed according to presence of steroidogenic enzyme autoantibodies (17alpha-hydroxylase, side chain cleavage, and 21-hydroxylase autoantibodies). RESULTS: AMH concentrations were significantly higher in women with SCA-POI than women with iPOI (P = 0.018) or PMW (P = 0.03) but significantly lower than HW (P < 0.0001). AMH was detected in 11 of 26 women with SCA-POI (42%) and seven of 66 with iPOI (11%) (P = 0.002). Serum concentrations above the fifth percentile of the normal range (0.6 ng/ml) were detected in nine of 26 women with SCA-POI (35%) and four of 66 with iPOI (6%) (P = 0.001). Eight of 12 women with SCA-POI with less than 5 yr (67%) and one of 14 with longer disease duration (7%) had AMH concentrations within the normal range (P = 0.003). AMH concentrations correlated inversely with disease duration in women with SCA-POI (rho = -0.563, P = 0.003) but not women with iPOI. AMH correlated inversely with FSH serum concentrations in HW (rho = -0.584, P < 0.001) but not PMW or women with POI. CONCLUSIONS: Two thirds of women with recent-onset SCA-POI had normal AMH concentrations. Women with SCA-POI, differently from those with iPOI, present a preserved ovarian follicle pool for several years after diagnosis of ovarian insufficiency.