Clonal Hematopoiesis of Indeterminate Potential and Diabetic Kidney Disease: A Nested Case-Control Study.

Introduction: The disease trajectory of diabetic kidney disease (DKD) shows a high interindividual variability not sufficiently explained by conventional risk factors. Clonal hematopoiesis of indeterminate potential (CHIP) is a proposed novel cardiovascular risk factor. Increased kidney fibrosis and glomerulosclerosis were described in mouse models of CHIP. Here, we aim to analyze whether CHIP affects the incidence or progression of DKD. Methods: A total of 1419 eligible participants of the PROVALID Study were the basis for a nested case-control (NCC) design. A total of 64 participants who reached a prespecified composite endpoint within the observation period (initiation of kidney replacement therapy, death from kidney failure, sustained 40% decline in estimated glomerular filtration rate or sustained progression to macroalbuminuria) were identified and matched to 4 controls resulting in an NCC sample of 294 individuals. CHIP was assessed via targeted amplicon sequencing of 46 genes in peripheral blood. Furthermore, inflammatory cytokines were analyzed in plasma via a multiplex assay. Results: The estimated prevalence of CHIP was 28.91% (95% CI 22.91%-34.91%). In contrast to other known risk factors (albuminuria, hemoglobin A1c, heart failure, and smoking) and elevated microinflammation, CHIP was not associated with incident or progressive DKD (hazard ratio [HR] 1.06 [95% CI 0.57-1.96]). Conclusions: In this NCC study, common risk factors as well as elevated microinflammation but not CHIP were associated with kidney function decline in type 2 diabetes mellitus.

Complement Potentiates Immune Sensing of HIV-1 and Early Type I Interferon Responses.

Complement-opsonized HIV-1 triggers efficient antiviral type I interferon (IFN) responses in dendritic cells (DCs), which play an important role in protective responses at the earliest stages in retroviral infection. In contrast, HIV-1 suppresses or escapes sensing by STING- and MAVS-associated sensors. Here, we identified a complement receptor-mediated sensing pathway, where DCs are activated in CCR5/RLR (RIG-I/MDA5)/MAVS/TBK1-dependent fashion. Increased fusion of complement-opsonized HIV-1 via complement receptor 4 and CCR5 leads to increased incoming HIV-1 RNA in the cytoplasm, sensed by a nonredundant cooperative effect of RIG-I and MDA5. Moreover, complement-opsonized HIV-1 down-modulated the MAVS-suppressive Raf-1/PLK1 pathway, thereby opening the antiviral recognition pathway via MAVS. This in turn was followed by MAVS aggregation and subsequent TBK1/IRF3/NF-κB activation in DCs exposed to complement- but not non-opsonized HIV-1. Our data strongly suggest that complement is important in the induction of efficient antiviral immune responses by preventing HIV-1 suppressive mechanisms as well as inducing specific cytosolic sensors. IMPORTANCE Importantly, our study highlights an unusual target on DCs-the α chain of complement receptor 4 (CR4) (CD11c)-for therapeutic interventions in HIV-1 treatment. Targeting CD11c on DCs mediated a potent antiviral immune response via clustering of CR4 and CCR5 and subsequent opening of an antiviral recognition pathway in DCs via MAVS. This novel finding might provide novel tools for specifically boosting endogenous antiviral immunity via CR4, abundantly expressed on multiple DC subsets.

ß-1,3-glucan-lacking Aspergillus fumigatus mediates an efficient antifungal immune response by activating complement and dendritic cells.

Complement system and dendritic cells (DCs) form - beside neutrophils and macrophages - the first line of defense to combat fungal infections. Therefore, we here studied interactions of these first immune elements with Aspergillus fumigatus lacking ß-1,3-glucans (fks1tetOnrep under repressed conditions) to mechanistically explain the mode of action of echinocandins in more detail. Echinocandins are cell wall active agents blocking ß-glucan synthase, making the A. fumigatus fks1tetOn mutant a good model to study immune-modulatory actions of these drugs. We now demonstrate herein, that complement was activated to significantly higher levels by the fks1-deficient strain compared to its respective wild type. This enhanced covalent linking of complement fragments to the A. fumigatus fks1tetOnrep mutant further resulted in enhanced DC binding and internalization of the fungus. Additionally, we found that fks1tetOnrep induced a Th1-/Th17-polarizing cytokine profile program in DCs. The effect was essentially dependent on massive galactomannan shedding, since blocking of DC-SIGN significantly reduced the fks1tetOnrep-mediated induction of an inflammatory cytokine profile.Our data demonstrate that lack of ß-1,3-glucan, also found under echinocandin therapy, results in improved recognition of Aspergillus fumigatus by complement and DCs and therefore not only directly affects the fungus by its fungistatic actions, but also is likely to exert indirect antifungal mechanisms by strengthening innate host immune mechanisms.Abbreviations: C: complement; CR:complement receptor; DC: dendritic cell; iDC: immature dendritic cell; DC-SIGN: Dendritic Cell-Specific Intercellular adhesion molecule-3-Grabbing Non-integrin; ERK: extracellular signal-regulated kinases; JNK : c-Jun N-terminal kinases; MAPK: mitogen-activated protein kinase; NHS: normal human serum; PRR: pattern recognition receptor; Th :T helper; TLR :Toll-like receptor; WT: wild type.

Oxidative Stress Response Tips the Balance in Aspergillus terreus Amphotericin B Resistance.

In this study, we characterize the impact of antioxidative enzymes in amphotericin B (AmB)-resistant (ATR) and rare AmB-susceptible (ATS) clinical Aspergillus terreus isolates. We elucidate expression profiles of superoxide dismutase (SOD)- and catalase (CAT)-encoding genes, enzymatic activities of SODs, and superoxide anion production and signaling pathways involved in the oxidative stress response (OSR) in ATS and ATR strains under AmB treatment conditions. We show that ATR strains possess almost doubled basal SOD activity compared to that of ATS strains and that ATR strains exhibit an enhanced OSR, with significantly higher sod2 mRNA levels and significantly increased cat transcripts in ATR strains upon AmB treatment. In particular, inhibition of SOD and CAT proteins renders resistant isolates considerably susceptible to the drug in vitro In conclusion, this study shows that SODs and CATs are crucial for AmB resistance in A. terreus and that targeting the OSR might offer new treatment perspectives for resistant species.

Promising immunotherapy against fungal diseases.

INTRODUCTION: Despite the relatively high efficacy of antifungal drugs, invasive fungal infections (IFIs) are still associated with tremendous morbidity and mortality, since late diagnosis makes an antifungal drug therapy inefficient. Therefore, antifungal immunotherapies to specifically strengthen the host´s own immune mechanisms constitute an additional promising strategy in taking action against fungal pathogens. Areas covered: The authors summarize efforts in research and clinical trials to provide safe and efficient immunotherapeutic options against invasive fungal diseases. Treatment of IFIs is challenging as the number of available antifungals is limited and further complications include: toxicity, drug interactions and the emergence of drug resistance. Susceptibility is determined by the impaired immune status of the host. Hence, augmenting immunity by immunotherapeutic interventions may offer future directions to treat IFI. Expert opinion: A much better understanding of fungus and host cell interactions is essential for the development of safe and successful immunotherapeutic strategies. Indeed, there is encouraging preliminary data available that such approaches are possible; however, current data is too limited to allow solid conclusions on the risks and benefits in the clinical setting. Clinical trials focusing on the role of adjuvant immunotherapeutics with or without a combination of antifungals are highly needed for further evaluation.

Complement-Opsonized HIV-1 Overcomes Restriction in Dendritic Cells.

DCs express intrinsic cellular defense mechanisms to specifically inhibit HIV-1 replication. Thus, DCs are productively infected only at very low levels with HIV-1, and this non-permissiveness of DCs is suggested to go along with viral evasion. We now illustrate that complement-opsonized HIV-1 (HIV-C) efficiently bypasses SAMHD1 restriction and productively infects DCs including BDCA-1 DCs. Efficient DC infection by HIV-C was also observed using single-cycle HIV-C, and correlated with a remarkable elevated SAMHD1 T592 phosphorylation but not SAMHD1 degradation. If SAMHD1 phosphorylation was blocked using a CDK2-inhibitor HIV-C-induced DC infection was also significantly abrogated. Additionally, we found a higher maturation and co-stimulatory potential, aberrant type I interferon expression and signaling as well as a stronger induction of cellular immune responses in HIV-C-treated DCs. Collectively, our data highlight a novel protective mechanism mediated by complement opsonization of HIV to effectively promote DC immune functions, which might be in the future exploited to tackle HIV infection.

Amphotericin B Resistance in Aspergillus terreus Is Overpowered by Coapplication of Pro-oxidants.

AIMS: Invasive fungal infections have significantly increased over the past decades in immunocompromised individuals and high-risk patients. Amphotericin B (AmB) exerts a powerful and broad activity against a vast array of fungi and has a remarkably low rate of microbial resistance. However, most isolates of Aspergillus terreus developed an intrinsic resistance against AmB, and during this study, we characterized the mode of action of this polyene antifungal drug in more detail in resistant (ATR) and rare susceptible (ATS) clinical isolates of A. terreus. RESULTS: We illustrate that AmB treatment changes cellular redox status and promotes the generation of high levels of reactive oxygen species (ROS) in ATS. In contrast, ATR isolates were able to cope better with AmB-induced oxidative stress. INNOVATION: Most importantly, we demonstrate in this study that coapplication of anti- and pro-oxidants significantly affects AmB efficacy in an antithetic manner--antioxidants and ROS-scavenging agents increase AmB tolerance in susceptible strains, while pro-oxidants render formerly resistant isolates considerably susceptible to the antifungal drug also in vivo in a Galleria animal model. CONCLUSION: Thereby, our study provides novel therapeutic options to treat formerly resistant fungal strains by a combination of AmB and pro-oxidant compounds.