Three Years On: The Role of Pegcetacoplan in Paroxysmal Nocturnal Hemoglobinuria (PNH) since Its Initial Approval.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disease characterized by complement-mediated hemolysis and potentially life-threatening complications. Pegcetacoplan, an inhibitor of complement components C3 and C3b, was approved by the US Food and Drug Administration (FDA) and European Medicines Agency (EMA) in 2021. A recent expansion to its indication by the EMA has made pegcetacoplan available for the treatment of both complement inhibitor-naïve and -experienced patients with PNH who have hemolytic anemia, a similarly broad patient population as in the US. This approval was based on results from the Phase 3 PEGASUS study, where pegcetacoplan showed superiority over the C5 inhibitor eculizumab with regard to improving the hemoglobin level in patients with anemia despite eculizumab treatment, and the Phase 3 PRINCE study, where pegcetacoplan showed superiority over supportive care with regard to hemoglobin stabilization and improving the lactate dehydrogenase level in complement inhibitor-naïve patients. In light of this recent indication expansion by the EMA, this article describes how the strong efficacy of pegcetacoplan is linked to its mechanism of action, which provides broad hemolysis control over both intravascular and extravascular hemolysis to improve a range of disease markers and enhance patients' quality of life. Furthermore, additional data and learnings obtained from over 3 years of experience with pegcetacoplan are summarized, including long-term efficacy and safety results, real-world clinical experiences, pharmacokinetic characteristics, and extensive practical guidance for the first-to-market proximal complement inhibitor for PNH.

Neutrophil-avid nanocarrier uptake by STAT3 dominant-negative hyper-IgE syndrome patient neutrophils.

Recurrent infections are a hallmark of STAT3 dominant-negative hyper-IgE syndrome (STAT3 HIES), a rare immunodeficiency syndrome previously known as Jobs syndrome, along with elevated IgE levels and impaired neutrophil function. We have been developing nanoparticles with neutrophil trophism that home to the sites of infection via these first-responder leukocytes, named neutrophil-avid nanocarriers (NANs). Here, we demonstrate that human neutrophils can phagocytose nanogels (NGs), a type of NAN, with enhanced uptake after particle serum opsonization, comparing neutrophils from healthy individuals to those with STAT3 HIES, where both groups exhibit NG uptake; however, the patient group showed reduced phagocytosis efficiency with serum-opsonized NANs. Proteomic analysis of NG protein corona revealed complement components, particularly C3, as predominant in both groups. Difference between groups includes STAT3 HIES samples with higher neutrophil protein and lower acute-phase protein expression. The study suggests that despite neutrophil dysfunction in STAT3 HIES, NANs have potential for directed delivery of cargo therapeutics to improve neutrophil infection clearance.

Moving toward Individual Treatment Goals with Pegcetacoplan in Patients with PNH and Impaired Bone Marrow Function.

Paroxysmal nocturnal haemoglobinuria (PNH) is a rare, potentially life-threatening haematological disease characterised by chronic complement-mediated haemolysis with multiple clinical consequences that impair quality of life. This post hoc analysis assessed haematological and clinical responses to the first targeted complement C3 inhibitor pegcetacoplan in patients with PNH and impaired bone marrow function in the PEGASUS (NCT03500549) and PRINCE (NCT04085601) studies. For patients with impaired bone marrow function, defined herein as haemoglobin <10 g/dL and absolute neutrophil count <1.5 × 109 cells/L, normalisation of the parameters may be difficult. Indeed, 20% and 43% had normalised haemoglobin in PEGASUS and PRINCE, respectively; 60% and 57% had normalised LDH, and 40% and 29% had normalised fatigue scores. A new set of parameters was applied using changes associated with clinically meaningful improvements, namely an increase in haemoglobin to ≥2 g/dL above baseline, decrease in LDH to ≤1.5× the upper limit of normal, and an increase in fatigue scores to ≥5 points above baseline. With these new parameters, 40% and 71% of PEGASUS and PRINCE patients had improved haemoglobin; 60% and 71% had an improvement in LDH, and 60% and 43% had an improvement in fatigue scores. Thus, even patients with impaired bone marrow function may achieve clinically meaningful improvements with pegcetacoplan.

C3 Glomerulopathy Recurs Early after Kidney Transplantation in Serial Biopsies Performed within the First 2 Years after Transplantation.

Background: C3 glomerulopathy (C3G), which encompasses C3GN and dense deposit disease (DDD), results from dysregulation of the alternative complement pathway. Data on disease recurrence after kidney transplantation are limited, and details on histologic features of recurrent C3G are scarce. We aimed to evaluate C3G recurrence in the allograft, with a focus on histologic presentation and progression. Methods: We retrospectively analyzed 18 patients with native kidney failure attributed to C3G (12 C3GN and six DDD), who received a kidney transplant from January 2016 to January 2023. Demographic, genetic, clinical, and histologic data were studied. The NanoString 770 genes PanCancer Immune Profiling Panel was used for transcriptomic analysis. Disease recurrence was the primary outcome. Results: During a median (interquartile range) follow-up period of 37 (18­56) months, C3G recurrence occurred in 16 (89%) patients (11 with C3GN and five with DDD) at a median (interquartile range) of 33 (13­141) days after transplantation. Over a third (38%) of recurrent cases were detected in protocol biopsies, and only 31% of patients presented with >300 mg/g of proteinuria. Recurrence in index biopsies was mainly established through a combination of immunofluorescence and electron microscopy findings, while it showed only subtle histologic alterations and no characteristic transcriptomic signals. Over time, histologic chronicity indices increased, but all the allografts were functioning at the end of follow-up. Patients with recurrence of C3GN and DDD showed overlapping immunofluorescence and electron microscopy findings and had similar recurrence rate and time to recurrence. Conclusions: Most of the patients with native kidney failure attributed to C3G developed disease recurrence very early after kidney transplantation, usually with minimal proteinuria, mild histologic alterations, and favorable short-term allograft survival. Immunofluorescence and electron microscopy played a crucial role in detecting early, subclinical recurrence of C3GN and DDD, which showed significant overlapping features.

Predictors of disease severity, length of hospitalization, and recurrence in inpatients with single-organ cutaneous small vessel vasculitis.

There is a lack of systematic studies on single-organ cutaneous small vessel vasculitis (SOCV). To evaluate prognostic clinical and laboratory parameters, including systemic immune-inflammation biomarkers (SIIB) in SOCV inpatients. This study investigated the clinical and laboratory data of 178 inpatients. Blood tests were performed at baseline. SIIB were assessed based on neutrophil-to-lymphocyte ratio (NLR) and pan-immune-inflammation value (PIV). Univariable and multivariable statistics were performed. Both NLR and PIV were significantly higher in SOCV patients than in healthy controls. However, the SIIB values observed in SOCV patients were as high as those in psoriasis patients. On logistic regression analysis, disease manifestation on the upper extremities strongly predicted the absence of severe disease (OR: 0.31, 95% CI: 0.13 to 0.73; p = 0.0071). Moreover, older age (OR: 2.3, 95% CI: 1.11 to 4.77; p = 0.025) and severe disease (OR: 2.4, 95% CI: 1.16 to 4.94, p = 0.018) were significant independent predictors of longer hospital stay, whereas female sex was an independent protective factor for longer hospitalization (OR: 0.52, 95% CI: 0.28 to 0.96, p = 0.038). Lower serum C3 was a strong independent predictor of disease recurrence (OR: 13.9, 95% CI 3 to 63.4; p = 0.0007). The increase in SIIB observed in patients with SOCV reflects that systemic inflammatory alterations also play a role in SOCV patients. We identified several clinical and laboratory-based independent predictors of SOCV severity, length of hospitalization, and disease recurrence that may aid prognostication of SOCV patients.

Level of Cytokines and C3 Complement in the Blood of Rats under Conditions of Chronic Unpredictable Stress of Different Durations.

The parameters of the cytokine profile and functional activity of the complement system in the blood of rats were studied during different time periods of chronic unpredictable mild stress using a model of sequentially alternating low-intensity stress effects for 1, 2, 3, and 4 weeks. In the dynamics of observation, a general tendency towards multidirectional fluctuations in the concentration of cytokines was revealed: an increase in IL-10, but a decrease in IL-4 in comparison with the control. Statistically significant changes in the level of IL-10 were noted after 2, 3, and 4 weeks, IL-4 - after 2 and 4 weeks of stress loads. The percentage of lysis of the C3 component in rats gradually increased by the 2nd week of chronic stress, but then decreased and practically did not differ from the control values (intact animals) by the end of the study. These results illustrate the specificity of changes in the indicators of the C component of the complement system and the cytokine profile of the blood reflecting activity of the cellular and humoral components of the immune response in rats exposed to repeated stress factors of different origins and duration.

Induction of astrocyte reactivity promotes neurodegeneration in human pluripotent stem cell models.

Reactive astrocytes are known to exert detrimental effects upon neurons in several neurodegenerative diseases, yet our understanding of how astrocytes promote neurotoxicity remains incomplete, especially in human systems. In this study, we leveraged human pluripotent stem cell (hPSC) models to examine how reactivity alters astrocyte function and mediates neurodegeneration. hPSC-derived astrocytes were induced to a reactive phenotype, at which point they exhibited a hypertrophic profile and increased complement C3 expression. Functionally, reactive astrocytes displayed decreased intracellular calcium, elevated phagocytic capacity, and decreased contribution to the blood-brain barrier. Subsequently, co-culture of reactive astrocytes with a variety of neuronal cell types promoted morphological and functional alterations. Furthermore, when reactivity was induced in astrocytes from patient-specific hPSCs (glaucoma, Alzheimer's disease, and amyotrophic lateral sclerosis), the reactive state exacerbated astrocytic disease-associated phenotypes. These results demonstrate how reactive astrocytes modulate neurodegeneration, significantly contributing to our understanding of a role for reactive astrocytes in neurodegenerative diseases.

Effects of the Pharmabiotic U-21 under Conditions of a Combined Neuroinflammatory Model of Parkinson's Disease in Rats.

Data on the participation of microbiota in the development of Parkinson's disease allow us to discuss the ability of bacterial preparations to influence the processes leading to neurodegeneration. We studied the effect of oral administration of Limosilactobacillus fermentum U-21 lyophilisate on a model of Parkinson's disease in rats induced by combined intranigral injection of LPS and systemic administration of paraquat. The toxins significantly increased the number of missteps in the "narrowing beam walking" test, but a tendency to a decrease in this parameter was shown after treatment with U-21. It should be noted that U-21 did not reduce the neuronal death in the substantia nigra, but mitigated the inflammatory glial response, decreased the accumulation of phosphorylated α-synuclein and complement protein C3. Our study demonstrated the efficiency of the combined model of parkinsonism and reduction of proinflammatory changes under the influence of pharmabiotic without changes in the nigral neuronal death and motor deficits.

The Establishment of Complement System Is from Gene Duplication and Domain Shuffling.

The mammalian complement system constitutes a highly sophisticated body defense machinery. The evolutionary origin of the complement system can be traced to Coelenterata as the presence of the central component C3 and two activation proteases BF and MASP. In the present study, the main complement components were screened and analyzed from the genomes of different species in metazoan subphyla/phyla. C1q with classical domains can be traced to Annelida, and ficolin and MBL to Urochordata. C1r and C1s are only found in Chondrichthyes and even higher species, and MASP is traced to Coelenterata. In the evolutionary tree, C1r from Vertebrates is close to MASP1/2/3 from Deuterostomia and Coelenterata, and C1s from Vertebrates is close to MASP-like protease (MASPL) from Arthropoda, Mollusca, and Annelida. C2, BF, and DF can be traced to Mollusca, Coelenterata, and Porifera, respectively. There are no clear C2 and BF branches in the evolutionary tree. C3 can be traced to Coelenterata, and C4 and C5 are only in Chondrichthyes and even higher species. There are three clear C3, C4, and C5 branches in the evolutionary tree. C6-like (C6L) and C8 can be traced to Urochordata, and C7-like (C7L) can be traced to Cephalochordara. C6L, C7L, and C8 from Urochordata and Cephalochordara provide the structural conditions for the formation of Vertebrate MAC components. The findings unveil the evolutionary principles of the complement system and provide insight into its sophistication.

Improvements in hematologic markers and decreases in fatigue with pegcetacoplan for patients with paroxysmal nocturnal hemoglobinuria and mild or moderate anemia (hemoglobin ≥10 g/dL) who had received eculizumab or were naive to complement inhibitors.

BACKGROUND: Although complement component 5 inhibitors (C5is) eculizumab and ravulizumab improve paroxysmal nocturnal hemoglobinuria (PNH) outcomes, patients may experience persistent anemia. This post hoc analysis investigated whether the complement component 3-targeted therapy pegcetacoplan also improved hematologic outcomes and reduced fatigue in patients with PNH and mild/moderate anemia. METHODS: Patients with PNH and hemoglobin ≥10.0 g/dL at baseline of PADDOCK (N = 6), PRINCE (N = 8), and PEGASUS (N = 11) were included. Before receiving pegcetacoplan, PADDOCK and PRINCE patients were C5i-naive; PEGASUS patients had hemoglobin <10.5 g/dL despite stably dosed eculizumab. Hemoglobin concentrations, percentages of patients with concentrations ≥12 g/dL, and sex-specific normalization were assessed at baseline and after 16 weeks of pegcetacoplan, as were absolute reticulocyte counts (ARCs) and normalization and fatigue scores and normalization. RESULTS: From baseline to week 16, mean (SD) hemoglobin concentrations increased in C5i-naive patients (PADDOCK: 10.5 [0.4] to 12.7 [1.1] g/dL; PRINCE: 11.3 [1.0] to 14.0 [1.3] g/dL) and those with suboptimal eculizumab responses (PEGASUS: 10.2 [0.2] to 12.8 [2.6] g/dL). Percentage of patients with hemoglobin ≥12 g/dL increased (PADDOCK: 0 to 60.0% [3 of 5 patients]; PRINCE: 25.0% [2 of 8] to 87.5% [7 of 8]; PEGASUS: 0 to 72.7% [8 of 11]). Sex-specific hemoglobin normalization at week 16 occurred in 40.0% (2 of 5) (PADDOCK), 62.5% (5 of 8) (PRINCE), and 63.6% (7 of 11) (PEGASUS). In all studies, mean ARCs decreased from above normal to normal and ARC normalization increased. Mean Functional Assessment of Chronic Illness Therapy-Fatigue scores improved from below to above or near normal. Two patients had serious adverse events (PEGASUS: post-surgery sepsis, breakthrough hemolysis); breakthrough hemolysis resolved without study discontinuation. CONCLUSION: Patients with PNH and mild/moderate anemia who were C5i-naive or who had suboptimal hemoglobin concentrations despite eculizumab treatment had improved hematologic outcomes and reduced fatigue after initiating or switching to pegcetacoplan. TRIAL REGISTRATION: Trial registration numbers: PADDOCK (NCT02588833), PRINCE (NCT04085601; EudraCT, 2018-004220-11), PEGASUS (NCT03500549).

Construction and application of fetal loss risk model in systemic lupus erythematosus patients with mild disease severity.

BACKGROUND: This dynamic nomogram model was developed to predict the probability of fetal loss in pregnant patients with systemic lupus erythematosus (SLE) with mild disease severity before conception. METHODS: An analysis was conducted on 314 pregnancy records of patients with SLE who were hospitalized between January 2015 and January 2022 at Shenzhen People's Hospital, and the Longhua Branch of Shenzhen People's Hospital. Data from the Longhua Branch of the Shenzhen People's Hospital were utilized as an independent external validation cohort. The nomogram, a widely used statistical visualization tool to predict disease onset, progression, prognosis, and survival, was created after feature selection using multivariate logistic regression analysis. To evaluate the model prediction performance, we employed the receiver operating characteristic curve, calibration curve, and decision curve analysis. RESULTS: Lupus nephritis, complement 3, immunoglobulin G, serum albumin, C-reactive protein, and hydroxychloroquine were all included in the nomogram model. The model demonstrated good calibration and discriminatory power, with an area under the curve of 0.867 (95% confidence interval: 0.787-0.947). According to decision curve analysis, the nomogram model exhibited clinical importance when the probability of fetal loss in patients with SLE ranged between 10 and 70%. The predictive ability of the model was demonstrated through external validation. CONCLUSION: The predictive nomogram approach may facilitate precise management of pregnant patients with SLE with mild disease severity before conception.

Altered Elastin Turnover, Immune Response, and Age-Related Retinal Thinning in a Transgenic Mouse Model With RPE-Specific HTRA1 Overexpression.

Purpose: A single-nucleotide polymorphism in HTRA1 has been linked to age-related macular degeneration (AMD). Here we investigated the potential links between age-related retinal changes, elastin turnover, elastin autoantibody production, and complement C3 deposition in a mouse model with RPE-specific human HTRA1 overexpression. Methods: HTRA1 transgenic mice and age-matched CD1 wild-type mice were analyzed at 6 weeks and 4, 6, and 12 to 14 months of age using in vivo retinal imaging by optical coherence tomography (OCT) and fundus photography, as well as molecular readouts, focusing on elastin and elastin-derived peptide quantification, antielastin autoantibody, and total Ig antibody measurements and immunohistochemistry to examine elastin, IgG, and C3 protein levels in retinal sections. Results: OCT imaging indicated thinning of inner nuclear layer as an early phenotype in HTRA1 mice, followed by age and age/genotype-related thinning of the photoreceptor layer, RPE, and total retina. HTRA1 mice exhibited reduced elastin protein levels in the RPE/choroid and increased elastin breakdown products in the retina and serum. A corresponding age-dependent increase of serum antielastin IgG and IgM autoantibodies and total Ig antibody levels was observed. In the RPE/choroid, these changes were associated with an age-related increase of IgG and C3 deposition. Conclusions: Our results confirm that RPE-specific overexpression of human HTRA1 induces certain AMD-like phenotypes in mice. This includes altered elastin turnover, immune response, and complement deposition in the RPE/choroid in addition to age-related outer retinal and photoreceptor layer thinning. The identification of elastin-derived peptides and corresponding antielastin autoantibodies, together with increased C3 deposition in the RPE/choroid, provides a rationale for an overactive complement system in AMD irrespective of the underlying genetic risk.

Role of serum complement C3 and C4 on kidney outcomes in IgA nephropathy.

IgA Nephropathy (IgAN) is the most prevalent glomerular disease worldwide. Complement system activation is crucial in its pathogenesis. Few studies correlated serum C3 and C4 with disease activity and prognosis. This retrospective study investigated the prognostic value of serum complement at the time of diagnosis in patients with IgAN. Specifically we evaluated whether adding serum C3 and C4 levels to established predictive models-one based on variables related to chronic kidney disease (CKD) progression and another incorporating variables from the International IgA Prediction Tool (IntIgAPT)-enhances the accuracy of outcome prediction. A composite renal outcome was defined as 50% decline in eGFR or onset of kidney failure. 101 patients were stratified according to baseline C3 levels in three groups (Low, Medium and High). During a median follow-up of 54 months, the Low group exhibited higher incidence of primary outcome (16.3 events vs 2.9 and 1.7 events × 100 pts/year, p = 0.0026). Model-1 (M1), consisting of CKD progression variables, and Model-3 (M3), comprising IntIgANPT variables, were implemented with baseline C3 and C4 to create Model-2 (M2) and Model-4 (M4), respectively. M2 demonstrated better predictive performance over M1, showing higher discrimination (lower AIC and BIC, higher C-index and NR2). Similarly, M4 outperformed M3, showing enhanced outcome prediction when C3 and C4 levels were added. Implementation of serum C3 and C4 can enhance prediction accuracy of already-validated prognostic models in IgAN. Lower C3 and higher C4 levels were associated with poorer prognosis, highlighting a more 'Complement-Pathic' subset of patients.

Intermittent pulses of methylprednisolone with low-dose prednisone attenuate lupus symptoms in B6.MRL-Faslpr/J mice with fewer glucocorticoid side effects.

Glucocorticoids (GCs) are potent anti-inflammatory and immunosuppressant medications and remain the cornerstone of systemic lupus erythematosus (SLE) therapy. However, ongoing exposure to GCs has the potential to elicit multiple adverse effects. Considering the irreplaceability of GCs in SLE therapy, it is important to explore the optimal regimen of GCs. Here, we compared the long-term efficacy and safety of pulsed and oral GC therapy in a lupus-prone mouse model. Mice were grouped using a randomized block design. We monitored survival rates, proteinuria, serum autoantibodies, and complement 3 (C3) levels up to 28 weeks of age, and assessed renal damage, bone quality, lipid deposition in the liver and marrow, glucose metabolic parameters, and levels of hormones of the hypothalamic-pituitary-adrenal (HPA) axis. Finally, we explored the mechanisms underlying the superior efficacy of the pulse regimen over oral prednisone regimen. We found that both GC regimens alleviated the poor survival rate, proteinuria, and glomerulonephritis, while also reducing serum autoantibodies and increasing the level of C3. The pulsed GC regimen showed less resistance to insulin, less suppression of the HPA axis, less bone loss, and less bone marrow fat deposition than the oral GC regimen. Additionally, GC-induced leucine zipper (GILZ) was significantly overexpressed in the GC pulse group. These results suggest that the GC pulse regimen ameliorated symptoms in lupus-prone mice, with fewer side effects, which may be related to GILZ overexpression. Our findings offer a potentially promising GC treatment option for SLE.

Correlation between neuropsychiatric systemic lupus erythematosus and immunological markers: a real-world retrospective study.

OBJECTIVES: This study aimed to investigate disparities in clinical profiles and autoantibody patterns between patients with and without neuropsychiatric systemic lupus erythematosus (NPSLE) in a cohort and to identify risk factors associated with NPSLE in the Chinese population. METHODS: SLE patients were retrospectively reviewed from two tertiary hospitals. The relationships between NPSLE and immunological biomarkers were explored. RESULTS: Among the 945 SLE patients, 75 (7.94%) were diagnosed with NPSLE. The most prevalent NP manifestations involved cognitive disorder (30.67%), headache (26.67%), seizure disorder (26.67%), and psychosis (26.67%).We observed significant associations between psychosis and anti-ß2GPI antibodies (F = 6.092, p = 0.015), polyneuropathy and anti-Scl70 antibodies (F = 20.161, p < 0.001), demyelinating syndrome and anti-cardiolipin antibodies (F = 6.637, p = 0.011), myasthenia gravis and anti-RNP (F = 5.864, p = 0.017), and anti-Smith antibodies (F = 5.096, p = 0.026). Multivariate logistics analysis showed that anti-prothrombin (aPT) IgM antibodies (OR = 10.985, CI 1.279-94.343, p = 0.029), age (OR = 1.169, CI 1.032-1.325, p = 0.014), and serum creatinine (SCr) (OR = 1.014, CI 1.003-1.025, p = 0.009) were independent risk factors of NPSLE, while anti-Sjogren syndrome antigen B (SSB) antibodies (OR 0.023, CI 0.002-0.622, p = 0.023) and high complement C3 (OR = 0.001, CI 0-0.045, p < 0.001) indicated reduced risk of NPSLE. CONCLUSION: Various neuropsychiatric manifestations in SLE were found to be correlated with specific autoantibodies. Independent risk factors for NPSLE included aPT IgM antibodies, age, and elevated serum creatinine, while the absence of anti-SSB antibodies and low complement C3 levels were associated with increased risk. KEY POINTS: •Significant associations were found between specific autoantibodies and neuropsychiatric symptoms, shedding light on potential biomarkers for predicting and understanding NPSLE. •The study identifies independent risk factors for NPSLE in the Chinese population, including the presence of anti-prothrombin IgM antibodies, older age, elevated serum creatinine, and lower complement C3 levels.

Integrity of neural extracellular matrix is required for microglia-mediated synaptic remodeling.

Microglia continuously remodel synapses, which are embedded in the extracellular matrix (ECM). However, the mechanisms, which govern this process remain elusive. To investigate the influence of the neural ECM in synaptic remodeling by microglia, we disrupted ECM integrity by injection of chondroitinase ABC (ChABC) into the retrosplenial cortex of healthy adult mice. Using in vivo two-photon microscopy we found that ChABC treatment increased microglial branching complexity and ECM phagocytic capacity and decreased spine elimination rate under basal conditions. Moreover, ECM attenuation largely prevented synaptic remodeling following synaptic stress induced by photodamage of single synaptic elements. These changes were associated with less stable and smaller microglial contacts at the synaptic damage sites, diminished deposition of calreticulin and complement proteins C1q and C3 at synapses and impaired expression of microglial CR3 receptor. Thus, our findings provide novel insights into the function of the neural ECM in deposition of complement proteins and synaptic remodeling by microglia.

Role of ginsenoside Rb1 in attenuating depression-like symptoms through astrocytic and microglial complement C3 pathway.

Ginsenoside Rb1, known as gypenoside III, exerts antidepressant-like effects in previous studies. It has also been indicated that ginsenoside Rb1 regulated neuroinflammation via inhibiting NF-κB signaling. According to the evidence that astrocytes can regulate microglia and neuroinflammation by secreting complement C3, the present study aimed to demonstrate the molecular mechanisms underlying ginsenoside Rb1-induced antidepressant-like effects from the astrocytic and microglial complement C3 pathway. The complement C3 mediated mechanism of ginsenoside Rb1 was investigated in mice exposed to chronic restraint stress (CRS). The results showed that ginsenoside Rb1 reversed the depressive-like behaviors in CRS. Treatment with ginsenoside Rb1 reduced both the number of astrocytes and microglia. In addition, ginsenoside Rb1 suppressed TLR4/NF-κB/C3 signaling in the astrocytes of the hippocampus. Furthermore, ginsenoside Rb1 attenuated the contents of synaptic protein including synaptophysin and PSD95 in microglia, suggesting the inhibition of microglia-mediated synaptic elimination caused by CRS. Importantly, ginsenoside Rb1 also maintained the dendritic spines in mice. In conclusion, our results demonstrate that ginsenoside Rb1 produces the antidepressant-like effects by inhibiting astrocyte TLR4/NF-κB/C3 signaling to covert microglia from a pro-inflammatory phenotype (amoeboid) towards an anti-inflammatory phenotype (ramified), which inhibit the synaptic pruning in the hippocampus.

Sialic acids on T cells are crucial for their maintenance and survival.

Sialic acids are found as terminal sugars on glycan structures on cellular surfaces. T cells carry these sialoglycans abundantly, and they are thought to serve multiple functions in cell adhesion, cell migration, and protection from complement attack. We studied the role of sialoglycans on T cells in a mouse model with a T cell-specific deletion of cytidine monophosphate-sialic acid synthase (CMAS), the enzyme that is crucial for the synthesis of sialoglycans. These mice showed a T-cell deficiency in peripheral lymphoid organs. Many T cells with an undeleted Cmas allele were found in the periphery, suggesting that they escaped the Cre-mediated deletion. The remaining peripheral T cells of T cell-specific Cmas KO mice had a memory-like phenotype. Additional depletion of the complement factor C3 could not rescue the phenotype, showing that the T-cell defect was not caused by a host complement activity. Cmas-deficient T cells showed a high level of activated caspase 3, indicating an ongoing apoptosis. In bone marrow chimeric cellular transfer experiments, we observed a strong competitive disadvantage of Cmas-deficient T cells compared to wild-type T cells. These results show that sialoglycans on the surface of T cells are crucial for T-cell survival and maintenance. This function has not been recognized before and is similar to the function of sialoglycans on B cells.

Update on C3 Glomerulopathy.

C3 glomerulopathy (C3G) is a rare disorder marked by deposition of C3 in the glomerulus, resulting in damage to the glomerular filtration unit and presenting with features of the nephritic and nephrotic syndromes. Fundamentally, C3G is caused by dysregulation of the alternative pathway of the complement cascade, either due to genetic variants or acquired humoral factors. Despite significant advances in recent years in the understanding of the underlying mechanisms and culprit lesions that result in the development of C3G, treatment options remain severely limited, and the prognosis is often poor. Fortunately, a number of anticomplement therapies are emerging from the drug development pipeline, with several in late-stage testing in patients with C3G, and there is hope that we will soon have more targeted options for managing patients with this devastating disease. In this review, we provide an overview of C3G, as well as summarizing the evidence for current treatments and detailing the clinical trials that are currently underway.

Association between circulatory complement activation and hypertensive renal damage: a case-control study.

OBJECTIVE: The aim of this study was to investigate the potential importance of complement system activation, with particular emphasis on the complement alternative pathway (AP), in the pathogenesis of hypertensive renal damage. METHODS: Serum complement C3, complement Factor H (CFH) and AP activation were assessed in 66 participants with established essential hypertension with renal damage (RD). Fifty-nine patients with age- and sex-matched essential hypertension without renal damage (NRD) and 58 healthy participants (normal) were selected. RESULTS: Our study revealed that C3 and AP50 continuously increased from normal to NRD to RD (p < 0.05, respectively), while CFH was significantly lower than that in NRD and healthy participants (p < 0.05, respectively). After multifactorial logistic regression analysis corrected for confounders, elevated serum C3 (p = 0.001) and decreased CFH (p < 0.001) were found to be independent risk factors for hypertension in healthy participants; elevated serum C3 (p = 0.034), elevated AP50 (p < 0.001), decreased CFH (p < 0.001), increased age (p = 0.011) and increased BMI (p = 0.013) were found to be independent risk factors for the progression of hypertension to hypertensive renal damage; elevated serum C3 (p = 0.017), elevated AP50 (p = 0.023), decreased CFH (p = 0.005) and increased age (p = 0.041) were found to be independent risk factors for the development of hypertensive renal damage in healthy participants. CONCLUSION: Abnormal activation of complement, particularly complement AP, may be a risk factor for the development and progression of hypertensive renal damage.