Conversion of the Liver into a Biofactory for DNaseI Using Adeno-Associated Virus Vector Gene Transfer Reduces Neutrophil Extracellular Traps in a Model of Systemic Lupus Erythematosus.

Adeno-associated virus (AAV) vectors are proving to be clinically transformative tools in the treatment of monogenic genetic disease. Rapid ongoing development of this technology promises to not only increase the number of monogenic disorders amenable to this approach but also to bring diseases with complex multigenic and nongenetic etiologies within therapeutic reach. In this study, we explore the broader paradigm of converting the liver into a biofactory for systemic output of therapeutic molecules using AAV-mediated delivery of the endonuclease DNaseI as an exemplar.

Adeno-Associated Virus Vector Gene Delivery Elevates Factor I Levels and Downregulates the Complement Alternative Pathway .

The complement system is a key component of innate immunity, but impaired regulation influences disease susceptibility, including age-related macular degeneration and some kidney diseases. While complete complement inhibition has been used successfully to treat acute kidney disease, key unresolved challenges include strategies to modulate rather than completely inhibit the system and to deliver therapy potentially over decades. Elevating concentrations of complement factor I (CFI) restricts complement activation and this approach was extended in the current study to modulate complement activation .

Functional expression of complement factor I following AAV-mediated gene delivery in the retina of mice and human cells.

Dry age-related macular degeneration (AMD) is characterised by loss of central vision and currently has no approved medical treatment. Dysregulation of the complement system is thought to play an important role in disease pathology and supplementation of Complement Factor I (CFI), a key regulator of the complement system, has the potential to provide a treatment option for AMD. In this study, we demonstrate the generation of AAV constructs carrying the human CFI sequence and expression of CFI in cell lines and in the retina of C57BL/6 J mice.

The story of complement factor I.

Factor I was first discovered in 1966. Its importance became apparent with the description of the original Factor I deficient patient in Boston in 1967. This patient presented with a hyperactive alternative complement pathway resulting in secondary complement deficiency due to continuous complement consumption.

A novel and sensitive functional assay for complement Factor I based on the third proteolytic clip of C3b.

A sensitive assay for the functional activity of complement Factor I is described. This is based on its third proteolytic clip whereby Factor I cleaves cell-bound iC3b to cell-bound C3dg and soluble C3c, thereby abolishing conglutination of the cells. Factor H is required as a co-factor for Factor I activity.

Looking back on the alternative complement pathway.

The alternative pathway of complement originated from the Properdin pathway originally described by the Pillemer laboratory in the 1950s. This work generated great controversy and it took several decades for a consensus on its components, its reaction sequence and its functions to emerge. This paper reviews this history and attempts to clarify some of the ambiguities that remain.

Experimental confirmation of the C3 tickover hypothesis by studies with an Ab (S77) that inhibits tickover in whole serum.

The complement component 3 (C3) tickover hypothesis was put forward in the early 1970s to account for the spontaneous activation of the alternative complement pathway that occurs after the genetic absence or depletion of Factor I, the enzyme that is essential for the breakdown of C3b. The hypothesis was widely accepted, but experimental demonstration of the tickover was elusive. A phage Ab against C3b that inhibited the alternative complement pathway, but not the classical pathway, was described in 2009.

A more radical solution.

The current modifications to licensing procedures still leave a basically flawed system in place. A more radical solution is proposed that involves dispensing with Phase 3 trials and making medicines available at the end of Phase 2 to those who are fully informed of the potential risks and benefits and wish to take part in this novel procedure. The advantages include a shorter development time, lower development costs and allowing smaller companies to take medicines to the clinic.

Low-dose recombinant properdin provides substantial protection against Streptococcus pneumoniae and Neisseria meningitidis infection.

Modern medicine has established three central antimicrobial therapeutic concepts: vaccination, antibiotics, and, recently, the use of active immunotherapy to enhance the immune response toward specific pathogens. The efficacy of vaccination and antibiotics is limited by the emergence of new pathogen strains and the increased incidence of antibiotic resistance. To date, immunotherapy development has focused mainly on cytokines.

The use of antibodies in the prophylaxis and treatment of infections.

The use of antibodies to provide passive immunity to infections has a long history. Although the coming of antibiotics greatly reduced its use for bacterial infections, it is still widely used for a variety of purposes which are reviewed here. The use of animal antisera gave way to the use of human convalescent serum as a source of antibodies and more recently human and monoclonal antibodies have become widely used, not just providing passive immunity but as therapeutic agents.

The grandmother effect.

Two classes of explanation have been advanced to explain women's long post-menopausal life span - that it is an epiphenomenon of increased longevity or an evolved adaptation. While there is no decisive evidence to choose between them, the latter appears more likely. Two mechanisms for the evolved adaptation have been proposed, the 'mother effect' and the 'grandmother effect'.

The amplification loop of the complement pathways.

The C3 amplification loop lies at the core of all the complement pathways, rather than the alternative pathway alone. It is, in evolutionary terms, the oldest part of the complement system and its antecedents can be seen in insects and in echinoderms. The amplification loop is the balance between two competing cycles both acting on C3b: the C3 feedback cycle which enhances amplification and the C3 breakdown cycle which downregulates it.

Streptococcal DRS (distantly related to SIC) and SIC inhibit antimicrobial peptides, components of mucosal innate immunity: a comparison of their activities.

"Streptococcal inhibitor of complement" (SIC) and "distantly related to SIC" (DRS) are related virulence factors secreted by M1 and M12 strains of GAS, respectively. The human mucosal innate immune system, important components of which are beta-defensins, secretory leukocyte proteinase inhibitor (SLPI) and lysozyme, provides the first line of defence against microorganisms. We report the interaction between DRS and these proteins; further investigations into the interaction of SIC with the beta-defensins; and compare the sensitivity of M12 and M1 GAS to SLPI.

The in vivo expression of actin/salt-resistant hyperactive DNase I inhibits the development of anti-ssDNA and anti-histone autoantibodies in a murine model of systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is characterised by the production of autoantibodies against ubiquitous antigens, especially nuclear components. Evidence makes it clear that the development of these autoantibodies is an antigen-driven process and that immune complexes involving DNA-containing antigens play a key role in the disease process. In rodents, DNase I is the major endonuclease present in saliva, urine and plasma, where it catalyses the hydrolysis of DNA, and impaired DNase function has been implicated in the pathogenesis of SLE.

Attribution of the various inhibitory actions of the streptococcal inhibitor of complement (SIC) to regions within the molecule.

Some strains of Streptococcus pyogenes secrete a virulence factor called the streptococcal inhibitor of complement (SIC) function. SIC is a polyfunctional protein that interacts with a number of host proteins and peptides, especially with those that are involved in host defense systems. In addition to inhibiting the complement-mediated lysis of cells, SIC inhibits lysozyme, secretory leukocyte proteinase inhibitor, and beta-defensins.

The interaction of streptococcal inhibitor of complement (SIC) and its proteolytic fragments with the human beta defensins.

Streptococcal inhibitor of complement (SIC) is a 31 kDa extracellular protein produced by a few highly virulent strains of Streptococcus pyogenes (in particular the M1 strain). It has been shown additionally to inhibit four further components of the mucosal innate response-lysozyme, secretory leucocyte proteinase inhibitor, human alpha-defensin 1 and the cathelicidin LL-37 which are all bactericidal against Group A Streptococci (GAS). We now show that SIC also inhibits variably the antibacterial action of hBD-1, -2 and -3.

Stem cell therapy: medical advance or moral challenge?

My professional lifetime has seen progress in the biomedical sciences that beggars belief. This has lead to astonishing advances in the ability to prevent and treat disease and, in the developed world at least, people live longer and healthier lives than ever before. Paradoxically, this has gone hand in hand with the growth of a vocal and influential anti-science lobby that not only rejects much modern science but is also deeply suspicious of new medical interventions.

Streptococcal inhibitor of complement inhibits two additional components of the mucosal innate immune system: secretory leukocyte proteinase inhibitor and lysozyme.

Streptococcal inhibitor of complement (SIC) is a 31-kDa extracellular protein of a few, very virulent, strains of Streptococcus pyogenes (particularly M1 strains). It is secreted in large quantities (about 5 mg/liter) and inhibits complement lysis by blocking the membrane insertion site on C5b67. We describe investigations into the interaction of SIC with three further major components of the innate immune system found in airway surface liquid, namely, secretory leukocyte proteinase inhibitor (SLPI), lysozyme, and lactoferrin.