Psoriasis is an inflammatory skin disease with strong neutrophil (PMN) infiltration and high levels of the antimicrobial peptide, LL37. LL37 in complex with DNA and RNA is thought to initiate disease ...exacerbation via plasmacytoid dendritic cells. However, the source of nucleic acids supposed to start this initial inflammatory event remains unknown. We show here that primary murine and human PMNs mount a fulminant and self-propagating neutrophil extracellular trap (NET) and cytokine response, but independently of the canonical NET component, DNA. Unexpectedly, RNA, which is abundant in NETs and psoriatic but not healthy skin, in complex with LL37 triggered TLR8/TLR13-mediated cytokine and NET release by PMNs in vitro and in vivo. Transfer of NETs to naive human PMNs prompts additional NET release, promoting further inflammation. Our study thus uncovers a self-propagating vicious cycle contributing to chronic inflammation in psoriasis, and NET-associated RNA (naRNA) as a physiologically relevant NET component.
Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) represent first-line standard of care in unresectable
mutation-positive (
m+) non-small cell lung cancer (NSCLC). However, ...10-20% of patients with
m+ NSCLC have uncommon
variants, defined as mutations other than L858R substitutions or exon 19 deletions. NSCLC harboring uncommon
mutations may demonstrate lower sensitivity to targeted agents than NSCLC with L858R or exon 19 deletion mutations. Prospective clinical trial data in patients with NSCLC uncommon
mutations are lacking. Afatinib is a second-generation TKI and the only Food and Drug Administration-approved drug for some of the more prevalent uncommon
mutations. We present a series of seven case reports describing clinical outcomes in afatinib-treated patients with NSCLC harboring a diverse range of extremely rare mutations with or without co-mutations affecting other genes.
alterations included compound mutations, P-loop αC-helix compressing mutations, and novel substitution mutations. We also present a case with NSCLC harboring a novel
::
gene fusion. Overall, the patients responded well to afatinib, including radiologic partial responses in six patients during treatment. Responses were durable for three patients. The cases presented are in line with a growing body of clinical and preclinical evidence that indicating that NSCLC with various uncommon
mutations, with or without co-mutations, may be sensitive to afatinib.
is a major human pathogen causing a variety of diseases ranging from common pharyngitis to life-threatening soft tissue infections and sepsis. Microbial nucleic acids, especially bacterial RNA, have ...recently been recognized as a major group of pathogen-associated molecular patterns (PAMPs) involved in the detection of
via endosomal Toll-like receptors (TLRs)
. However, the individual contribution and cooperation between TLRs as well as cell-type and strain specific differences in dependency on nucleic acid detection during
infection
have not been clarified in detail. Moreover, the role of particularly bacterial RNA for the defense of
infection
remains poorly defined. In this study, we report that in all investigated innate immune cells involved in the resolution of bacterial infections, including murine macrophages, dendritic cells and neutrophils, recognition of
strain ATCC12344 is almost completely dependent on nucleic acid sensing via endosomal TLRs at lower MOIs, whereas at higher MOIs, detection via TLR2 plays an additional, yet redundant role. We further demonstrate that different
strains display a considerable inter-strain variability with respect to their nucleic acid dependent recognition. Moreover, TLR13-dependent recognition of
RNA is largely non-redundant in bone marrow-derived macrophages (BMDMs), but less relevant in neutrophils and bone marrow-derived myeloid dendritic cells (BMDCs) for the induction of an innate immune response
.
, we show that a loss of nucleic acid sensing blunts early recognition of
, leading to a reduced local containment of the bacterial infection with subsequent pronounced systemic inflammation at later time points. Thus, our results argue for a crucial role of nucleic acid sensing via endosomal TLRs in defense of
infection both
and
.
Cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy (HIPEC) was considered a promising treatment for patients with peritoneal metastasis from colorectal cancer. However, the ...recently published randomized controlled PRODIGE 7 trial failed to demonstrate survival benefits through the addition of short-term oxaliplatin-based HIPEC. Constituting a complex multifactorial treatment, we investigated HIPEC in a preclinical model concerning the elimination of minimal tumor residues, thereby aiming to better understand the size of effects and respective clinical trial results. Patient samples of peritoneal perfusates obtained during HIPEC treatments and oxaliplatin-containing solutions at clinically relevant dosages, conforming with established HIPEC protocols, were assessed regarding their ability to eliminate modelled ~100 µm thickness cancer cell layers. Impedance-based real-time cell analysis and classical end-point assays were used. Flow cytometry was employed to determine the effect of different HIPEC drug solvents on tumor cell properties. Effectiveness of peritoneal perfusate patient samples and defined oxaliplatin-containing solutions proved limited but reproducible. HIPEC simulations for 30 min reduced the normalized cell index below 50% with peritoneal perfusates from merely 3 out of 9 patients within 72 h, indicating full-thickness cytotoxic effects. Instead, prolonging HIPEC to 1 h enhanced these effects and comprised 7 patients' samples, while continuous drug exposure invariably resulted in complete cell death. Further, frequently used drug diluents caused approximately 25% cell size reduction within 30 min. Prolonging oxaliplatin exposure improved effectiveness of HIPEC to eliminate micrometastases in our preclinical model. Accordingly, insufficient penetration depth, short exposure time, and the physicochemical impact of drug solvents may constitute critical factors.
Platelets have long been known as mediators of hemostasis and, more recently, as mediators of thromboinflammation, although their physiopathological role has mostly been investigated in the context ...of disease of internal organs, such as liver and kidney, or systemic disorders. Of late, exciting recent data suggest that platelets may also play a role in inflammation at distal sites such as the skin: recent studies show that platelets, by engaging polymorphonuclear neutrophils (PMNs), contribute to local inflammation in the frequent skin disorder, psoriasis. In an experimental model, systemic depletion of platelets drastically attenuated skin inflammation by preventing PMN infiltration of the skin. A broader role of platelets in different types of skin inflammation is therefore likely, and in this paper, we specifically review recent advances in psoriasis. Special emphasis is given to the crosstalk with systemic platelet effects, which may be of interest in psoriasis-related cardiovascular comorbidities. Furthermore, we discuss the potential for platelet-centered interventions in the therapy for psoriasis.
Staphylococcus aureus is a facultative pathogen found on skin and nasal surfaces. It is usually absent from the skin of healthy humans but frequently colonizes the skin of patients with atopic ...dermatitis. Here, we investigate the functional role of neutrophils in the initial steps of S. aureus skin colonization and how skin commensals modulate the S. aureus–induced recruitment of neutrophils to the skin. Using an epicutaneous mouse skin colonization model, we show that skin inflammation induced by tape-stripping leads to a rapid recruitment of neutrophils, which correlates with enhanced S. aureus skin colonization. Interestingly, the depletion of neutrophils in vivo reduces S. aureus colonization, and in vitro coculture of primary human keratinocytes with neutrophils promotes S. aureus adherence. We demonstrate that the interaction of neutrophil extracellular traps with keratinocytes are responsible for the increased S. aureus skin colonization. Finally, we show that S. epidermidis as part of the skin microbiota can reduce the neutrophil recruitment induced by S. aureus infection. These data suggest that microbiota-mediated skin protection against S. aureus is dampened in an inflammatory environment in which neutrophil extracellular traps released by infiltrating neutrophils unexpectedly contribute to enhanced S. aureus skin colonization.
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Activity of the NLRP3 inflammasome, a critical mediator of inflammation, is controlled by accessory proteins, posttranslational modifications, cellular localization, and oligomerization. How these ...factors relate is unclear. We show that a well-established drug target, Bruton's tyrosine kinase (BTK), affects several levels of NLRP3 regulation. BTK directly interacts with NLRP3 in immune cells and phosphorylates four conserved tyrosine residues upon inflammasome activation, in vitro and in vivo. Furthermore, BTK promotes NLRP3 relocalization, oligomerization, ASC polymerization, and full inflammasome assembly, probably by charge neutralization, upon modification of a polybasic linker known to direct NLRP3 Golgi association and inflammasome nucleation. As NLRP3 tyrosine modification by BTK also positively regulates IL-1β release, we propose BTK as a multifunctional positive regulator of NLRP3 regulation and BTK phosphorylation of NLRP3 as a novel and therapeutically tractable step in the control of inflammation.
Chitin is the second most abundant polysaccharide in nature and linked to fungal infection and asthma. However, bona fide immune receptors directly binding chitin and signaling immune activation and ...inflammation have not been clearly identified because polymeric crude chitin with unknown purity and molecular composition has been used. By using defined chitin (N‐acetyl‐glucosamine) oligomers, we here identify six‐subunit‐long chitin chains as the smallest immunologically active motif and the innate immune receptor Toll‐like receptor (TLR2) as a primary fungal chitin sensor on human and murine immune cells. Chitin oligomers directly bind TLR2 with nanomolar affinity, and this fungal TLR2 ligand shows overlapping and distinct signaling outcomes compared to known mycobacterial TLR2 ligands. Unexpectedly, chitin oligomers composed of five or less subunits are inactive, hinting to a size‐dependent system of immuno‐modulation that appears conserved in plants and humans. Since blocking of the chitin‐TLR2 interaction effectively prevents chitin‐mediated inflammation in vitro and in vivo, our study highlights the chitin‐TLR2 interaction as a potential target for developing novel therapies in chitin‐related pathologies and fungal disease.
Synopsis
Chitin, a polysaccharide linked to fungal infection and allergic asthma, directly binds to the innate immune receptor TLR2 and triggers inflammation dependent on oligomer size. Blocking the chitin‐TLR2 interaction effectively prevents chitin‐mediated inflammation.
Oligomeric chains of fungal chitin directly bind to TLR2 and trigger inflammation.
Blocking of the chitin‐TLR2 interaction prevents chitin‐mediated inflammation in vitro and in vivo.
Size‐dependent chitin recognition based on oligomers is found in both plants and humans.
Chitin, a polysaccharide linked to fungal infection and allergic asthma, directly binds to the innate immune receptor TLR2 and triggers inflammation dependent on oligomer size. Blocking the chitin‐TLR2 interaction effectively prevents chitin‐mediated inflammation.
•Combined EGFRi/METi is effective in EGFR+ NSCLC with acquired MET dysregulation.•EGFR+ MET-amplified tumors had improved rwPFS with EGFRi/METi compared to SoC.•In contrast, with MET polysomy, ...efficacy of EGFRi/METI and SoC was comparable.
MET amplification is a common resistance mechanism to EGFR inhibition in EGFR-mutant non-small cell lung cancer (NSCLC). Several trials showed encouraging results with combined EGFR and MET inhibition (EGFRi/METi). However, MET amplification has been inconsistently defined and frequently included both polysomy and true amplification.
This is a multicenter, real-world analysis in patients with disease progression on EGFR inhibition and MET copy number gain (CNG), defined as either true amplification (MET to centromere of chromosome 7 ratio MET-CEP7 ≥ 2) or polysomy (gene copy number ≥ 5, MET-CEP7 < 2).
A total of 43 patients with MET CNG were included, 42 of whom were detected by FISH. Twenty-three, 7, and 14 received EGFRi/METi, METi, and SoC, respectively. Patients in the EGFRi/METi cohort exhibited a superior real-world clinical benefit rate, defined as stable disease or better, of 82% (95% confidence interval CI, 60-95) compared to METi (29%, 4-71) and SoC (50%, 23-77). Median real-world progression-free survival was longer with EGFRi/METi with 9.8 vs. 4.3 months with METi (hazard ratio HR, 0.19, 95% CI, 0.06-0.57) and 3.7 months with SoC (0.41, 0.18-0.91), respectively. Overall survival was numerically improved. Interaction analysis with treatment and type of CNG (amplification vs. polysomy) suggests that differences were exclusively driven by MET-amplified patients receiving EGFRi/METi (HR for OS, 0.09, 0.01-0.54).
In this real-world study, EGFRi/METi showed clinical benefit over METi and SoC. Future studies should focus on the differential impact of the type of MET CNG with a focus on true MET amplification as predictor of response.
MET amplification is a common resistance mechanism to EGFR inhibition in NSCLC. However, the term MET amplification has been used inconsistently and frequently included polysomy. In this retrospective study, patients with true MET amplification rather than polysomy derived clinical benefit from combined MET and EGFR inhibition compared to SoC.
Sequencing of tumour tissue with comprehensive gene panels is increasingly used to guide treatment in precision oncology. Analysis of tumour–normal pairs allows in contrast to tumour-only assessment ...direct discrimination between somatic and germline alterations, which might have important implications not only for the patients but also their families.
We performed tumour normal sequencing with a large gene panel in 1048 patients with advanced cancer to support treatment decision. Sequencing results were correlated with clinical and family data.
We identified 156 likely pathogenic or pathogenic (LP/P) germline variants in cancer predisposition genes (CPGs) in 144 cases (13.7%). Of all patients, 8.8% had a LP/P variant in autosomal-dominant cancer predisposition genes (AD-CPGs), most of them being genes with high or moderate penetrance (ATM, BRCA2, CHEK2 and BRCA1). In 48 cases, the P/LP variant matched the expected tumour spectrum. A second variant in tumour tissue was found in 31 patients with AD-CPG variants. Low frequency mutations in either TP53, ATM or DNMT3A in the normal sample indicated clonal haematopoiesis in five cases.
Tumour–normal testing for personalised treatment identifies germline LP/P variants in a relevant proportion of patients with cancer. The majority of them would not have been referred to genetic counselling based on family history. Indirect functional readouts of tumour–normal sequencing can provide novel links between CPGs and unexpected cancers. The interpretation of increasingly complex datasets in precision oncology is challenging and concepts of interdisciplinary personalised cancer prevention are needed to support patients and their families.
•Significant amount of relevant germline variants is detected by blood-tumour testing.•Carriers do not always fulfil clinical criteria for cancer predisposition.•Blood–Tumour testing identifies novel links between cancer predisposition genes and cancer types.•Family-specific screening strategies are required when cancer predisposition genes are found in atypical tumours.
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