Generation and Characterization of Mouse Models of C3 Glomerulonephritis With CFI D288G and P467S Mutations

C3 glomerulopathy (C3GP) is a disease entity caused by abnormality of the complement alternative pathway (AP) and characterized by C3 deposition in glomeruli. Many variations or mutations of complement factors are believed to underlie the susceptibility to C3GP, but there is a lack of experimental evidence. We have recently reported a patient with C3 glomerulonephritis (C3GN) and compound heterozygosity of two novel variations in the complement factor (CFI). Here, we generated a mouse model to mimic the CFI variations for studying pathogenicity of CFI variations in C3GN development. We used the CRISPR/Cas9 system to make mutant mouse lines that carried D288G and P467S mutations in CFI, respectively, and crossed them to generate mice with compound heterozygosity of CFI D288G and P467S. The mice were all normal in either SPF (specific pathogen free) or regular environment. When treated with lipopolysaccharides (LPS), a bacterial endotoxin that mimics infection and sepsis, the mice developed albuminuria, kidney function impairment, and C3 glomerular deposition at levels comparable with the wild-type mice. The mice with other genotypes concerning CFI D288G and P467S were also tested in parallel. Unexpectedly, we found that the D288G homozygotes all developed severe mesangial deposition of C3 in the LPS model, indicating that CFI D288G variation was involved in the C3 deposition, a key feature of C3GN. The mouse lines generated in the present study can be used to further study the role of CFI variations in C3GN development; in addition, they may be used to screen and test infections and environmental factors capable of triggering C3GN.

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New functional and structural insights from updated mutational databases for complement factor H, Factor I, membrane cofactor protein and C3

Bioscience Reports ◽

10.1042/bsr20140117 ◽

2014 ◽

Vol 34 (5) ◽

Cited By ~ 41

Author(s):

Elizabeth Rodriguez ◽

Pavithra M. Rallapalli ◽

Amy J. Osborne ◽

Stephen J. Perkins

Keyword(s):

Alternative Pathway ◽

Factor H ◽

Complement Factor H ◽

Complement C3 ◽

Complement Factor ◽

Membrane Cofactor Protein ◽

Complement Alternative Pathway ◽

Factor I ◽

Mutational Hotspots ◽

Structural Insights

A new compilation of 324 mutations in four major proteins from the complement alternative pathway reveals mutational hotspots in factor H and complement C3, and less so in factor I and membrane cofactor protein. Their associations with function are discussed.

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Inhibition of complement alternative pathway by ACH-4471, the first clinical investigational orally-administered inhibitor of complement factor D

Molecular Immunology ◽

10.1016/j.molimm.2017.06.226 ◽

2017 ◽

Vol 89 ◽

pp. 200-201 ◽

Cited By ~ 1

Author(s):

Mingjun Huang ◽

Wengang Yang ◽

Steven D. Podos ◽

Guangwei Yang ◽

Yongsen Zhao ◽

...

Keyword(s):

Alternative Pathway ◽

Complement Factor ◽

Complement Alternative Pathway

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The Role of Properdin in C5 Convertase Activity and C5b-9 Formation in the Complement Alternative Pathway

The Journal of Immunology ◽

10.4049/jimmunol.2100238 ◽

2021 ◽

pp. ji2100238

Author(s):

Marloes A. H. M. Michels ◽

Rianne J. F. Maas ◽

Thea J. A. M. van der Velden ◽

Nicole C. A. J. van de Kar ◽

Lambertus P. W. J. van den Heuvel ◽

...

Keyword(s):

Alternative Pathway ◽

Complement Alternative Pathway

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Complement Factor D protects mice from ethanol-induced inflammation and liver injury

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00334.2017 ◽

2018 ◽

Vol 315 (1) ◽

pp. G66-G79 ◽

Cited By ~ 14

Author(s):

Rebecca L. McCullough ◽

Megan R. McMullen ◽

Megan M. Sheehan ◽

Kyle L. Poulsen ◽

Sanjoy Roychowdhury ◽

...

Keyword(s):

Liver Injury ◽

Complement Activation ◽

Alternative Pathway ◽

Chronic Ethanol ◽

Apoptotic Cells ◽

Complement Factor ◽

Complement Protein ◽

Short Term ◽

Pathway Activation

Complement plays a crucial role in microbial defense and clearance of apoptotic cells. Emerging evidence suggests complement is an important contributor to alcoholic liver disease. While complement component 1, Q subcomponent (C1q)-dependent complement activation contributes to ethanol-induced liver injury, the role of the alternative pathway in ethanol-induced injury is unknown. Activation of complement via the classical and alternative pathways was detected in alcoholic hepatitis patients. Female C57BL/6J [wild type (WT)], C1q-deficient ( C1qa−/−, lacking classical pathway activation), complement protein 4-deficient ( C4−/−, lacking classical and lectin pathway activation), complement factor D-deficient ( FD−/−, lacking alternative pathway activation), and C1qa/FD−/− (lacking classical and alternative pathway activation) mice were fed an ethanol-containing liquid diet or pair-fed control diet for 4 or 25 days. Following chronic ethanol exposure, liver injury, steatosis, and proinflammatory cytokine expression were increased in WT but not C1qa−/−, C4−/−, or C1qa/FD−/− mice. In contrast, liver injury, steatosis, and proinflammatory mediators were robustly increased in ethanol-fed FD−/− mice compared with WT mice. Complement activation, assessed by hepatic accumulation of C1q and complement protein 3 (C3) cleavage products (C3b/iC3b/C3c), was evident in livers of WT mice in response to both short-term and chronic ethanol. While C1q accumulated in ethanol-fed FD−/− mice (short term and chronic), C3 cleavage products were detected after short-term but not chronic ethanol. Consistent with impaired complement activation, chronic ethanol induced the accumulation of apoptotic cells and fibrogenic responses in the liver of FD−/− mice. These data highlight the protective role of complement factor D (FD) and suggest that FD-dependent amplification of complement is an adaptive response that promotes hepatic healing and recovery in response to chronic ethanol. NEW & NOTEWORTHY Complement, a component of the innate immune system, is an important pathophysiological contributor to ethanol-induced liver injury. We have identified a novel role for factor D, a component of the alternative pathway, in protecting the liver from ethanol-induced inflammation, accumulation of apoptotic hepatocytes, and profibrotic responses. These data indicate a dual role of complement with regard to inflammatory and protective responses and suggest that accumulation of apoptotic cells impairs hepatic healing/recovery during alcoholic liver disease.

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Association between thrombotic microangiopathy and activated alternative complement pathway in malignant nephrosclerosis

Nephrology Dialysis Transplantation ◽

10.1093/ndt/gfaa280 ◽

2020 ◽

Author(s):

Ying Zhang ◽

Chaona Yang ◽

Xinjin Zhou ◽

Ruimin Hu ◽

Songxia Quan ◽

...

Keyword(s):

Thrombotic Microangiopathy ◽

Alternative Pathway ◽

Factor H ◽

Complement Factor ◽

Complement Alternative Pathway ◽

Complement Components ◽

Atypical Haemolytic Uraemic Syndrome ◽

Urinary Levels ◽

Normal Controls ◽

Malignant Nephrosclerosis

Abstract Background Malignant nephrosclerosis, defined as renal microangiopathy in the setting of severe hypertension, remains a critical renal emergency leading to end-stage renal disease despite aggressive anti-hypertensive treatment. Recently, activation of the complement alternative pathway (AP) has been reported to play a prominent role in the pathogenesis of malignant nephrosclerosis. However, subsequent study failed to recapitulate the findings of genetic complement abnormalities in the disease. This study aimed to determine the presence of AP activation and genetic complement defects and establish their correlations to renal microangiopathy lesions, clinical features and prognosis in patients with malignant nephrosclerosis. Methods Fifty patients with malignant hypertension and concomitant thrombotic microangiopathy (TMA) proven by renal biopsy were investigated; 25 cases of kidney donors who received zero-hour allograft biopsies were used as normal controls. Various renal TMA lesions in patients with malignant nephrosclerosis were reviewed and evaluated using a semi-quantitative scoring system. Deposition of C5b-9, C3a, C5a, C4d and mannose-binding lectin was assessed by immunohistochemistry. Co-localization of C5b-9 and CD34 was detected by confocal microscopy. Complement factor B (FB), factor P (FP; properdin), factor D (FD), factor H (FH), C3a and C5a levels were quantified by enzyme-linked immonosorbent assay in plasma and urine samples of patients with malignant nephrosclerosis and controls. Genetic abnormalities of complement components were analysed by whole-exome sequencing. Results Renal biopsies of malignant nephrosclerosis showed identical histopathological and ultrastructural features to atypical haemolytic uraemic syndrome. C5b-9, C3a and C5a deposits were found along the walls of arteries/arterioles and glomerular capillaries and localized in the endothelial cells. Elevated plasma and urinary levels of FB, FP, FD, C3a and C5a as well as decreased FH levels were observed in patients with malignant nephrosclerosis compared with normal controls. The urinary levels of complement AP components, but not the plasma levels, were correlated with renal functions, prognosis and active TMA lesions except for arteriolar thrombi. Finally, mutations of the MCP, CFB, CFH and CFHR5 genes were identified in 8 of 20 patients with malignant nephrosclerosis. Conclusions Aberrant complement AP dysregulation was demonstrated and associated with the activity, severity and renal outcomes of malignant nephrosclerosis. This observation warrants screening for complement defects in patients with malignant nephrosclerosis for the potential use of complement regulators and also highlights the need for further investigation of the precise role of AP in the pathogenesis of the disease.

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Changes in complement alternative pathway components, factor B and factor H during dengue virus infection in the AG129 mouse

Journal of General Virology ◽

10.1099/jgv.0.001547 ◽

2021 ◽

Author(s):

Sheila Cabezas-Falcon ◽

Aidan J. Norbury ◽

Jarrod Hulme-Jones ◽

Sonja Klebe ◽

Penelope Adamson ◽

...

Keyword(s):

Dengue Virus ◽

Alternative Pathway ◽

Severe Disease ◽

Denv Infection ◽

Factor H ◽

Severe Dengue ◽

Complement Alternative Pathway ◽

Factor B ◽

Dengue Disease

The complement alternative pathway (AP) is tightly regulated and changes in two important AP components, factor B (FB) and factor H (FH) are linked to severe dengue in humans. Here, a mouse model of dengue was investigated to define the changes in FB and FH and assess the utility of this model to study the role of the AP in severe dengue. Throughout the period of viremia in the AG129 IFN signalling-deficient mouse, an increase in FB and a decrease in FH was observed following dengue virus (DENV) infection, with the former only seen in a model of more severe disease associated with antibody-dependent enhancement (ADE). Terminal disease was associated with a decrease in FB and FH, with greater changes during ADE, and accompanied by increased C3 degradation consistent with complement activation. In silico analysis of NFκΒ, signal transducer and activator of transcription (STAT) and IFN-driven FB and FH promoter elements to reflect the likely impact of the lack of IFN-responses in AG129 mice, demonstrated that these elements differed markedly between human and mouse, notably with mouse FH lacking NFκΒ and key IFN-stimulated response elements (ISRE), and FB with many more NFκΒ and STAT-responsive elements than human FB. Thus, the AG129 mouse offers utility in demonstrating changes in FB and FH that, similar to humans, are associated with severe disease, but lack predicted important human-specific and IFN-dependent responses of FB and FH to DENV-infection that are likely to regulate the subtleties of the overall AP response during dengue disease in humans.

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Danicopan: an oral complement factor D inhibitor for paroxysmal nocturnal hemoglobinuria

Haematologica ◽

10.3324/haematol.2020.261826 ◽

2020 ◽

pp. 0-0

Author(s):

Antonio M. Risitano ◽

Austin G. Kulasekararaj ◽

Jong Wook Lee ◽

Jaroslaw P. Maciejewski ◽

Rosario Notaro ◽

...

Keyword(s):

Patient Reported Outcomes ◽

Paroxysmal Nocturnal Hemoglobinuria ◽

Alternative Pathway ◽

Dose Finding ◽

Complement Factor ◽

Open Label ◽

Complement Alternative Pathway ◽

Serious Adverse Event ◽

Patient Reported ◽

Open Label Phase

Paroxysmal nocturnal hemoglobinuria (PNH) is characterised by complement-mediated intravascular hemolysis (IVH) due to absence of complement regulators CD55 and CD59 on affected erythrocytes. Danicopan is a first-in-class oral proximal, complement alternative pathway factor D (FD) inhibitor. Therapeutic FD inhibition was designed to control IVH and prevent C3-mediated extravascular hemolysis (EVH). In this open-label, phase 2, dose-finding trial, 10 untreated hemolytic PNH patients received danicopan monotherapy (100-200 mg thrice daily). Endpoints included change in lactate dehydrogenase (LDH) at day 28 (primary) and day 84 and hemoglobin. Safety, pharmacokinetics/pharmacodynamics, and patient-reported outcomes were measured. Ten patients reached the primary endpoint; two later discontinued: one for a serious adverse event (elevated aspartate aminotransferase/alanine aminotransferase coincident with breakthrough hemolysis, resolving without sequelae) and one for personal reasons unrelated to safety. Eight patients completed treatment. IVH was inhibited, demonstrated by mean decreased LDH (5.7 times upper limit of normal [ULN] at baseline vs 1.8 times ULN [day 28] and 2.2 times ULN [day 84]; both p

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The Critical Role of Complement Alternative Pathway Regulator Factor H in Allergen-Induced Airway Hyperresponsiveness and Inflammation

The Journal of Immunology ◽

10.4049/jimmunol.1101813 ◽

2011 ◽

Vol 188 (2) ◽

pp. 661-667 ◽

Cited By ~ 21

Author(s):

Katsuyuki Takeda ◽

Joshua M. Thurman ◽

Stephen Tomlinson ◽

Masakazu Okamoto ◽

Yoshiki Shiraishi ◽

...

Keyword(s):

Airway Hyperresponsiveness ◽

Alternative Pathway ◽

Critical Role ◽

Factor H ◽

Complement Alternative Pathway

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The role of complement system and other inflammatory factors in the development of age-related macular degeneration

Kazan medical journal ◽

10.17816/kmj2018-657 ◽

2018 ◽

Vol 99 (4) ◽

pp. 657-664

Author(s):

E A Abdulaeva

Keyword(s):

Macular Degeneration ◽

Complement System ◽

Genetic Factors ◽

Alternative Pathway ◽

Factor H ◽

Age Related Macular Degeneration ◽

Inflammatory Factors ◽

Complement Factor ◽

Age Related

The article is a review of literature on the role of complement system and inflammatory factors in the development of age-related macular degeneration. The review uses materials of domestic and foreign researchers. The clinical characteristics of age-related macular degeneration are presented, the role of genetic factors, complement factors, biomarkers of inflammation and alternative pathway of complement activation in the pathogenesis and risk of age-related macular degeneration is determined. Age-related macular degeneration is a chronic progressive multifactorial disease that affects macular area of the retina and is the main cause of loss of central vision in patients of older age group. The most important genetic factors are chromosome 1 (1q32) including complement factor H and complement factor H related genes and chromosome 10 (10q31). Variants associated with a moderate effect on developmental risk were identified in C3, complement factor I and complement factor B genes. In the pathogenesis of age-related macular degeneration, the key role is played by the damaged regulation of the alternative complement pathway. Single nucleotide polymorphisms in complement genes that affect the risk of development of age-related macular degeneration are predominantly involved in the alternative pathway of activation of the complement system. In pathomorphological studies, the initial localization of the pathological process of this pathology was established to be a complex of retinal pigment epithelium, Bruch’s membrane, and choriocapillaries followed by loss of photoreceptor function. The review of studies of systemic inflammatory biomarkers, cytokines, vascular endothelial growth factors in peripheral blood, blood serum, aqueous humour at various stages and forms of age-related macular degeneration is presented.

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