Author Correction: Consistent success in life-supporting porcine cardiac xenotransplantation.

In this Letter, Mayuko Kurome and Valeri Zakhartchenko have been added to the author list (affiliated with Institute of Molecular Animal Breeding and Biotechnology, Gene Center, LMU Munich, Munich, Germany). The author list and 'Author contributions' section have been corrected online; see accompanying Amendment.

Consistent success in life-supporting porcine cardiac xenotransplantation.

Heart transplantation is the only cure for patients with terminal cardiac failure, but the supply of allogeneic donor organs falls far short of the clinical need1-3. Xenotransplantation of genetically modified pig hearts has been discussed as a potential alternative4. Genetically multi-modified pig hearts that lack galactose-α1,3-galactose epitopes (α1,3-galactosyltransferase knockout) and express a human membrane cofactor protein (CD46) and human thrombomodulin have survived for up to 945 days after heterotopic abdominal transplantation in baboons5. This model demonstrated long-term acceptance of discordant xenografts with safe immunosuppression but did not predict their life-supporting function. Despite 25 years of extensive research, the maximum survival of a baboon after heart replacement with a porcine xenograft was only 57 days and this was achieved, to our knowledge, only once6. Here we show that α1,3-galactosyltransferase-knockout pig hearts that express human CD46 and thrombomodulin require non-ischaemic preservation with continuous perfusion and control of post-transplantation growth to ensure long-term orthotopic function of the xenograft in baboons, the most stringent preclinical xenotransplantation model. Consistent life-supporting function of xenografted hearts for up to 195 days is a milestone on the way to clinical cardiac xenotransplantation7.

Expanding the phenotypic spectrum of FINCA (fibrosis, neurodegeneration, and cerebral angiomatosis) syndrome beyond infancy.

Fibrosis, neurodegeneration, and cerebral angiomatosis (FINCA, MIM#618278) is a rare clinical condition caused by bi-allelic variants in NHL repeat containing protein 2 (NHLRC2, MIM*618277). Pulmonary disease may be the presenting sign and the few patients reported so far, all deceased in early infancy. Exome sequencing was performed on patients with childhood interstitial lung disease (chILD) and additional neurological features. The chILD-EU register database and an in-house database were searched for patients with NHLRC2 variants and clinical features overlapping FINCA syndrome. Six patients from three families were identified with bi-allelic variants in NHLRC2. Two of these children died before the age of two while four others survived until childhood. Interstitial lung disease was pronounced in almost all patients during infancy and stabilized over the course of the disease with neurodevelopmental delay (NDD) evolving as the key clinical finding. We expand the phenotype of FINCA syndrome to a multisystem disorder with variable severity. FINCA syndrome should also be considered in patients beyond infancy with NDD and a history of distinct interstitial lung disease. Managing patients in registers for rare diseases helps identifying new diagnostic entities and advancing care for these patients.

One-year outcomes in a multicentre cohort study of incident rare diffuse parenchymal lung disease in children (ChILD).

We performed a prospective, observational, cohort study of children newly diagnosed with children's interstitial lung disease (ChILD), with structured follow-up at 4, 8, 12 weeks and 6 and 12 months. 127 children, median age 0.9 (IQR 0.3-7.9) years had dyspnoea (68%, 69/102), tachypnoea (75%, 77/103) and low oxygen saturation (SpO2) median 92% (IQR 88-96). Death (n=20, 16%) was the most common in those <6 months of age with SpO2<94% and developmental/surfactant disorders. We report for the first time that ChILD survivors improved multiple clinical parameters within 8-12 weeks of diagnosis. These data can inform family discussions and support clinical trial measurements.

Lung disease in STAT3 hyper-IgE syndrome requires intense therapy.

BACKGROUND: Pulmonary complications are responsible for high morbidity and mortality rates in patients with the rare immunodeficiency disorder STAT3 hyper-IgE syndrome (STAT3-HIES). The aim of this study was to expand knowledge about lung disease in STAT3-HIES. METHODS: The course of pulmonary disease, radiological and histopathological interrelations, therapeutic management, and the outcome of 14 STAT3-HIES patients were assessed. RESULTS: The patients' quality of life was compromised most by pulmonary disease. All 14 patients showed first signs of lung disease at a median onset of 1.5 years of age. Lung function revealed a mixed obstructive-restrictive impairment with reduced FEV1 and FVC in 75% of the patients. The severity of lung function impairment was associated with Aspergillus fumigatus infection and prior lung surgery. Severe lung tissue damage, with reduced numbers of ATP-binding cassette sub-family A member 3 (ABCA3) positive type II pneumocytes, was observed in the histological assessment of two deceased patients. Imaging studies of all patients above 6 years of age showed severe airway and parenchyma destruction. Lung surgeries frequently led to complications, including fistula formation. Long-term antifungal and antibacterial treatment proved to be beneficial, as were inhalation therapy, chest physiotherapy, and exercise. Regular immunoglobulin replacement therapy tended to stabilize lung function. CONCLUSIONS: Due to its severity, pulmonary disease in STAT3-HIES patients requires strict monitoring and intensive therapy.

Early onset children's interstitial lung diseases: Discrete entities or manifestations of pulmonary dysmaturity?

Interstitial lung diseases in children (chILD) are rare and diverse. The current classifications include a group of early onset chILD specific to infancy, namely neuro-endocrine cell hyperplasia of infancy (NEHI), pulmonary interstitial glycogenosis (PIG) and the alveolar capillary-congenital acinar dysplasia (ACD-CAD) spectrum, as well as alveolar growth disorders. NEHI and PIG cells are seen in the normal developing foetal lung. We hypothesise that these conditions are in fact overlapping manifestations of pulmonary dysmaturity, respectively of airway, mesenchymal and vascular elements, rather than discrete clinical conditions in their own right. Clinically, these present as respiratory distress in early life. Mild cases rightly never undergo lung biopsy, and for these the clinical description 'persistent tachypnoea of infancy' has been proposed. In terms of pathology, we reviewed current literature, which showed that NEHI cells decline with age, and are not specific to NEHI, which we confirmed by unpublished re-analysis of a second dataset. Furthermore, specific genetic disorders which affect pulmonary maturation lead to a histological picture indistinguishable from NEHI. PIG and ACD-CAD are also associated with pulmonary growth disorders, and manifestations of PIG and NEHI may be present in the same child. We conclude that, contrary to current classifications, NEHI, PIG, and ACD-CAD should be considered as overlapping manifestations of pulmonary dysmaturation, frequently associated with disorders of alveolar growth, rather than as separate conditions. Identification of one of these patterns should be the start, not the end of the diagnostic journey, and underlying in particular genetic causes should be sought.

International management platform for children's interstitial lung disease (chILD-EU).

BACKGROUND: Children's interstitial lung diseases (chILD) cover many rare entities, frequently not diagnosed or studied in detail. There is a great need for specialised advice and for internationally agreed subclassification of entities collected in a register.Our objective was to implement an international management platform with independent multidisciplinary review of cases at presentation for long-term follow-up and to test if this would allow for more accurate diagnosis. Also, quality and reproducibility of a diagnostic subclassification system were assessed using a collection of 25 complex chILD cases. METHODS: A web-based chILD management platform with a registry and biobank was successfully designed and implemented. RESULTS: Over a 3-year period, 575 patients were included for observation spanning a wide spectrum of chILD. In 346 patients, multidisciplinary reviews were completed by teams at five international sites (Munich 51%, London 12%, Hannover 31%, Ankara 1% and Paris 5%). In 13%, the diagnosis reached by the referring team was not confirmed by peer review. Among these, the diagnosis initially given was wrong (27%), imprecise (50%) or significant information was added (23%).The ability of nine expert clinicians to subcategorise the final diagnosis into the chILD-EU register classification had an overall exact inter-rater agreement of 59% on first assessment and after training, 64%. Only 10% of the 'wrong' answers resulted in allocation to an incorrect category. Subcategorisation proved useful but training is needed for optimal implementation. CONCLUSIONS: We have shown that chILD-EU has generated a platform to help the clinical assessment of chILD. TRIAL REGISTRATION NUMBER: Results, NCT02852928.

Interlaboratory concordance of PD-L1 immunohistochemistry for non-small-cell lung cancer.

AIMS: Programmed death ligand 1 (PD-L1) immunohistochemistry has become a mandatory diagnostic test in the treatment of lung cancer. Several research initiatives have started to harmonise the five PD-L1 immunohistochemistry assays that have been used in clinical trials. Here, we report data on interlaboratory and interassay concordance for commercial assays ('assays') and laboratory-developed tests (LDTs) at 10 German testing sites. METHODS AND RESULTS: To assess interlaboratory concordance, a tissue microarray containing 21 pulmonary carcinoma specimens was centrally prepared. Pre-cut sections were stained at 10 sites by the use of assays 28-8, 22C3, SP263, and SP142, as well as 11 LDTs. Assay performance was evaluated with a second tissue microarray containing 11 cell lines with defined PD-L1 expression. Quality control was centrally performed by manual and digital analyses. The assays yielded reproducible IHC staining patterns at all sites. In agreement with previous studies, 22C3, 28-8 and SP263 showed similar staining patterns, whereas SP142 was distinct. Among the LDTs, six of 11 protocols showed staining patterns similar to those of assays 22C3 and 28-8. Interlaboratory concordance of tumour cell scoring by use of a six-step system was moderate (Light's κ = 0.43-0.69), whereas the clinically approved cut-offs of ≥1% and ≥50% showed substantial concordance (κ = 0.73-0.89). Immune cell scoring by the use of SP142 yielded moderate concordance (κ = 0.42). CONCLUSIONS: The data confirm the previously described staining patterns of the assays, and show that they can be reproducibly employed at different sites. LDTs with staining results similar to those of the assays are implementable, but have to be carefully validated.

NSCLC Patients Harbouring Rare or Complex EGFR Mutations Are More Often Smokers and Might Not Benefit from First-Line Tyrosine Kinase Inhibitor Therapy.

BACKGROUND: Generally, tyrosine kinase inhibitor (TKI) therapy is recommended in first-line treatment of patients with advanced non-small cell lung cancer (NSCLC) harbouring a classic epidermal growth factor receptor (EGFR) mutation. However, the response of patients with rare or complex EGFR mutations to TKI treatment is not predictable, nor is the prognosis for such patients. OBJECTIVES: In cases of rare or complex EGFR mutations, the right approach to therapy remains challenging. That is why we sought to analyse the characteristics as well as the prognosis and the response to TKI treatment of patients with rare or complex EGFR mutations. PATIENTS AND METHODS: 343 NSCLC patients tested for EGFR mutation at a German lung cancer centre were analysed for age, gender, and smoking status as well as for the mutation status. For 12 patients with rare and complex mutations, response to TKI treatment was described. RESULTS: 282 of all patients had a wild-type EGFR, whereas 61 harboured an EGFR mutation. 32 of these were classic mutations, followed by 16 rare and 7 complex mutations. EGFR mutations were significantly more frequent in women. Patients with rare or complex mutations were significantly more often smokers compared to those with classic EGFR mutations. Furthermore, rare and complex mutations were less responsive to TKI therapy. CONCLUSION: Patients with rare or complex EGFR mutations differ from those with classic mutations in terms of smoking status and response to TKIs. As these mutations may not respond well to TKI therapy, first-line TKIs should not be automatically chosen based on the sole presence of an EGFR mutation.

Idiopathic Pulmonary Fibrosis Among Young Patients: Challenges in Diagnosis and Management.

INTRODUCTION: Idiopathic pulmonary fibrosis (IPF) is considered a disease of older patients, being rare in patients ≤ 50 years. Still, IPF can occur in younger patients, but this particular patient group is not well characterised so far. The aim of this study was to compare the diagnostic certainty, clinical features, comorbidities and survival in young versus older IPF patients. METHODS: We reviewed our medical records from February 2011 until February 2015, to identify IPF patients, who were then classified as young (≤ 50 years) or older IPF (> 50 years). Radiographic and histological findings, lung function parameters, comorbidities, disease progression and survival were analysed and compared between the two groups. RESULTS: Of 440 patients with interstitial lung disease, 129 patients with IPF were identified, including 30 (23.3%) ≤50 years and 99 (76.7%) > 50 years. There were no differences between age groups in baseline demographics; younger patients were less likely to have a confirmed diagnosis by high-resolution computed tomography (p = 0.014), more likely to require a biopsy (p = 0.08) and less likely to have received antifibrotic therapy (p = 0.006). Despite an overall limited prognosis, younger patients had a significantly better median survival after diagnosis (p = 0.0375), with a significantly higher proportion of older patients dying due to respiratory failure (p = 0.0383). CONCLUSION: IPF patients under the age of 50 years have similar features and clinical course compared to older IPF patients. These patients should be diagnosed by adopting a multidisciplinary team approach, potentially benefitting from earlier intervention with effective antifibrotic therapy.

Lung disease caused by ABCA3 mutations.

BACKGROUND: Knowledge about the clinical spectrum of lung disease caused by variations in the ATP binding cassette subfamily A member 3 (ABCA3) gene is limited. Here we describe genotype-phenotype correlations in a European cohort. METHODS: We retrospectively analysed baseline and outcome characteristics of 40 patients with two disease-causing ABCA3 mutations collected between 2001 and 2015. RESULTS: Of 22 homozygous (15 male) and 18 compound heterozygous patients (3 male), 37 presented with neonatal respiratory distress syndrome as term babies. At follow-up, two major phenotypes are documented: patients with (1) early lethal mutations subdivided into (1a) dying within the first 6 months or (1b) before the age of 5 years, and (2) patients with prolonged survival into childhood, adolescence or adulthood. Patients with null/null mutations predicting complete ABCA3 deficiency died within the 1st weeks to months of life, while those with null/other or other/other mutations had a more variable presentation and outcome. Treatment with exogenous surfactant, systemic steroids, hydroxychloroquine and whole lung lavages had apparent but many times transient effects in individual subjects. CONCLUSIONS: Overall long-term (>5 years) survival of subjects with two disease-causing ABCA3 mutations was <20%. Response to therapies needs to be ascertained in randomised controlled trials.

Persistent Tachypnea of Infancy. Usual and Aberrant.

RATIONALE: Persistent tachypnea of infancy (PTI) is a specific clinical entity of undefined etiology comprising the two diseases neuroendocrine cell hyperplasia of infancy (NEHI) and pulmonary interstitial glycogenosis. The outcome of typical NEHI is favorable. The outcome may be different for patients without a typical NEHI presentation, and thus a lung biopsy to differentiate the diseases is indicated. OBJECTIVES: To determine whether infants with the characteristic clinical presentation and computed tomographic (CT) imaging of NEHI (referred to as "usual PTI") have long-term outcome and biopsy findings similar to those of infants with an aberrant presentation and/or with additional localized minor CT findings (referred to as "aberrant PTI"). METHODS: In a retrospective cohort study, 89 infants with PTI were diagnosed on the basis of clinical symptoms and, if available, CT scans and lung biopsies. Long-term outcome in childhood was measured on the basis of current status. MEASUREMENTS AND MAIN RESULTS: Infants with usual PTI had the same respiratory and overall outcomes during follow-up of up to 12 years (mean, 3.8 yr) as infants who had some additional localized minor findings (aberrant PTI) visualized on CT images. Both usual and aberrant PTI had a relatively favorable prognosis, with 50% of the subjects fully recovered by age 2.6 years. None of the infants died during the study period. This was independent of the presence or absence of histological examination. CONCLUSIONS: PTI can be diagnosed on the basis of typical history taking, clinical findings, and a high-quality CT scan. Further diagnostic measures, including lung biopsies, may be limited to rare, complicated cases, reducing the need for an invasive and potentially harmful procedure.

Harmonized PD-L1 immunohistochemistry for pulmonary squamous-cell and adenocarcinomas.

Immunohistochemistry of the PD-L1 protein may be predictive for anti-PD-1 and anti-PD-L1 immunotherapy in pulmonary adenocarcinoma and in clinically unselected cohorts of so-called non-small-cell lung cancer. Several PD-L1 immunohistochemistry assays with custom reagents and scoring-criteria are developed in parallel. Biomarker testing and clinical decision making would profit from harmonized PD-L1 diagnostics. To assess interobserver concordance and PD-L1 immunohistochemistry staining patterns, 15 pulmonary carcinoma resection specimens (adenocarcinoma: n=11, squamous-cell carcinoma: n=4) were centrally stained with the assays 28-8, 22C3, SP142, and SP263 according to clinical trial protocols. The slides were evaluated independently by nine pathologists. Proportions of PD-L1-positive carcinoma cells and immune cells were scored according to a 6-step system that integrates the criteria employed by the four PD-L1 immunohistochemistry assays. Proportion scoring of PD-L1-positive carcinoma cells showed moderate interobserver concordance coefficients for the 6-step scoring system (Light's kappa=0.47-0.50). The integrated dichotomous proportion cut-offs (≥1, ≥5, ≥10, ≥50%) showed good concordance coefficients (κ=0.6-0.8). Proportion scoring of PD-L1-positive immune cells yielded low interobserver concordance coefficients both for the 6-step-score (κ<0.2) and the dichotomous cut-offs (κ=0.12-0.25). The assays 28-8 and 22C3 stained similar proportions of carcinoma cells in 12 of 15 cases. SP142 stained fewer carcinoma cells compared to 28-8, 22C3, and SP263 in four cases, whereas SP263 stained more carcinoma cells in nine cases. SP142 and SP263 stained immune cells more intensely. The data indicate that carcinoma cells can be reproducibly scored in PD-L1 immunohistochemistry for pulmonary adenocarcinoma and squamous-cell carcinoma. No differences in interobserver concordance were noticed among the tested assays. The scoring of immune cells yielded low concordance rates and might require specific standardization. The four tested PD-L1 assays did not show comparable staining patterns in all cases. Thus, studies that correlate staining patterns and response to immunotherapy are required to test the significance of the observed differences.

Genotype alone does not predict the clinical course of SFTPC deficiency in paediatric patients.

Patients with interstitial lung disease due to surfactant protein C (SFTPC) mutations are rare and not well characterised. We report on all subjects collected over a 15-year period in the kids-lung register with interstitial lung disease and a proven SFTPC mutation. We analysed clinical courses, interventions and outcomes, as well as histopathological and radiological interrelations. 17 patients (seven male) were followed over a median of 3 years (range 0.3-19). All patients were heterozygous carriers of autosomal dominant SFTPC mutations. Three mutations (p.L101P, p.E191 K and p.E191*) have not been described before in the context of surfactant protein C deficiency. Patients with alterations in the BRICHOS domain of the protein (amino acids 94-197) presented earlier. At follow-up, one patient was healthy (2 years), six patients were "sick-better" (2.8 years, range 0.8-19), seven patients were "sick-same" (6.5 years, 1.3-15.8) and three patients were "sick-worse" (0.3 years, 0.3-16.9). Radiological findings changed from ground-glass to increasing signs of fibrosis and cyst formation with increasing age. Empiric treatments had variable effects, also in patients with the same genotype. Prospective studies with randomised interventions are urgently needed and can best be performed in the framework of international registers.

Caveolin-1 protects B6129 mice against Helicobacter pylori gastritis.

Caveolin-1 (Cav1) is a scaffold protein and pathogen receptor in the mucosa of the gastrointestinal tract. Chronic infection of gastric epithelial cells by Helicobacter pylori (H. pylori) is a major risk factor for human gastric cancer (GC) where Cav1 is frequently down-regulated. However, the function of Cav1 in H. pylori infection and pathogenesis of GC remained unknown. We show here that Cav1-deficient mice, infected for 11 months with the CagA-delivery deficient H. pylori strain SS1, developed more severe gastritis and tissue damage, including loss of parietal cells and foveolar hyperplasia, and displayed lower colonisation of the gastric mucosa than wild-type B6129 littermates. Cav1-null mice showed enhanced infiltration of macrophages and B-cells and secretion of chemokines (RANTES) but had reduced levels of CD25+ regulatory T-cells. Cav1-deficient human GC cells (AGS), infected with the CagA-delivery proficient H. pylori strain G27, were more sensitive to CagA-related cytoskeletal stress morphologies ("humming bird") compared to AGS cells stably transfected with Cav1 (AGS/Cav1). Infection of AGS/Cav1 cells triggered the recruitment of p120 RhoGTPase-activating protein/deleted in liver cancer-1 (p120RhoGAP/DLC1) to Cav1 and counteracted CagA-induced cytoskeletal rearrangements. In human GC cell lines (MKN45, N87) and mouse stomach tissue, H. pylori down-regulated endogenous expression of Cav1 independently of CagA. Mechanistically, H. pylori activated sterol-responsive element-binding protein-1 (SREBP1) to repress transcription of the human Cav1 gene from sterol-responsive elements (SREs) in the proximal Cav1 promoter. These data suggested a protective role of Cav1 against H. pylori-induced inflammation and tissue damage. We propose that H. pylori exploits down-regulation of Cav1 to subvert the host's immune response and to promote signalling of its virulence factors in host cells.

Cancer Stem Cell Markers Are Associated With Distant Hematogenous Liver Metastases But Not With Peritoneal Carcinomatosis in Colorectal Cancer.

Although peritoneal carcinomatosis (PC) displays advanced stage in colorectal cancer (CRC), most patients present without distant metastases. To analyze the expression of cancer stem cell markers immunohistochemistry for CD133, CD44 and ß-catenin was applied to CRC with exclusive PC, exclusive hepatic metastasis and CRC with combined spread. Expression of cancer stem cell markers correlated with hematogeneous metastases to the liver and was absent in patients with exclusive PC. Thus, expression of cancer stem cell markers correlates with different patterns of metastatic spread in CRC. These data indicate that CRC with exclusive PC lack stem cell features needed for distant dissemination.

Complete pathological response to neoadjuvant pemetrexed/cisplatin in combination with regional hyperthermia in a patient with sarcomatoid peritoneal mesothelioma.

Diffuse malignant peritoneal mesothelioma (DMPM) is a rare disease. Although most patients eligible for surgery undergo cytoreductive surgery in combination with hyperthermic intraperitoneal chemotherapy, the role of perioperative systemic chemotherapy still remains undefined. Here we report the case of a 52-year-old female patient with advanced sarcomatoid DMPM. After five cycles of systemic pemetrexed and cisplatin, along with two cycles of regional hyperthermia, tumor resection with histomorphological examination showed a complete pathological response. We therefore conclude that there is a subgroup of DMPM patients that might benefit from systemic neoadjuvant chemotherapy with pemetrexed and cisplatin.

Endonasal resection of early stage squamous cell carcinoma of the nasal vestibule.

The squamous cell carcinoma of the nasal vestibule (SCCNV) is a comparatively rare malignant disease. It occurs in the transition zone at the limen nasi. The choice of treatment for small tumors is a matter of controversy. Due to better cosmetic results, radiation therapy is usually recommended, however some recent reports have suggested that early stage tumors are equally or even more effectively managed by surgery. There was no standardized surgical procedure applied in these studies, though. The goal of our investigation was the retrospective evaluation of patients with a T1 or T2 carcinoma of the nasal vestibule who were treated surgically with an endonasal, endoscope-controlled approach at our ENT clinic between 2008 and 2010. Given the rarity of SCCNV, the 10 included cases represent the largest group of patients with early stage SCCNV treated primarily surgically by an endonasal approach so far. Our study shows that the endonasal resection of an early stage vestibular carcinoma seems adequate as a possible therapy. In the follow-up observation period no local or loco-regional recurrence was observed. The external cosmetic damage and endonasal scarring do not appear to be pronounced even following cartilage resection and were regarded as not seriously disadvantageous.

Activation of cannabinoid receptor 2 reduces inflammation in acute experimental pancreatitis via intra-acinar activation of p38 and MK2-dependent mechanisms.

The endocannabinoid system has been shown to mediate beneficial effects on gastrointestinal inflammation via cannabinoid receptors 1 (CB(1)) and 2 (CB(2)). These receptors have also been reported to activate the MAP kinases p38 and c-Jun NH(2)-terminal kinase (JNK), which are involved in early acinar events leading to acute pancreatitis and induction of proinflammatory cytokines. Our aim was to examine the role of cannabinoid receptor activation in an experimental model of acute pancreatitis and the potential involvement of MAP kinases. Cerulein pancreatitis was induced in wild-type, CB(1)-/-, and MK2-/- mice pretreated with selective cannabinoid receptor agonists or antagonists. Severity of pancreatitis was determined by serum amylase and IL-6 levels, intracellular activation of pancreatic trypsinogen, lung myeloperoxidase activity, pancreatic edema, and histological examinations. Pancreatic lysates were investigated by Western blotting using phospho-specific antibodies against p38 and JNK. Quantitative PCR data, Western blotting experiments, and immunohistochemistry clearly show that CB(1) and CB(2) are expressed in mouse pancreatic acini. During acute pancreatitis, an upregulation especially of CB(2) on apoptotic cells occurred. The unselective CB(1)/CB(2) agonist HU210 ameliorated pancreatitis in wild-type and CB(1)-/- mice, indicating that this effect is mediated by CB(2). Furthermore, blockade of CB(2), not CB(1), with selective antagonists engraved pathology. Stimulation with a selective CB(2) agonist attenuated acute pancreatitis and an increased activation of p38 was observed in the acini. With use of MK2-/- mice, it could be demonstrated that this attenuation is dependent on MK2. Hence, using the MK2-/- mouse model we reveal a novel CB(2)-activated and MAP kinase-dependent pathway that modulates cytokine expression and reduces pancreatic injury and affiliated complications.

The HDAC2-SP1 Axis Orchestrates Protumor Macrophage Polarization.

Tumor-associated macrophages (TAM), including antitumor M1-like TAMs and protumor M2-like TAMs, are transcriptionally dynamic innate immune cells with diverse roles in lung cancer development. Epigenetic regulators are key in controlling macrophage fate in the heterogeneous tumor microenvironment. Here, we demonstrate that the spatial proximity of HDAC2-overexpressing M2-like TAMs to tumor cells significantly correlates with poor overall survival of lung cancer patients. Suppression of HDAC2 in TAMs altered macrophage phenotype, migration, and signaling pathways related to interleukins, chemokines, cytokines, and T-cell activation. In coculture systems of TAMs and cancer cells, suppressing HDAC2 in TAMs resulted in reduced proliferation and migration, increased apoptosis of cancer cell lines and primary lung cancer cells, and attenuated endothelial cell tube formation. HDAC2 regulated the M2-like TAM phenotype via acetylation of histone H3 and transcription factor SP1. Myeloid cell-specific deletion of Hdac2 and pharmacologic inhibition of class I HDACs in four different murine lung cancer models induced the switch from M2-like to M1-like TAMs, altered infiltration of CD4+ and CD8+ T cells, and reduced tumor growth and angiogenesis. TAM-specific HDAC2 expression may provide a biomarker for lung cancer stratification and a target for developing improved therapeutic approaches. SIGNIFICANCE: HDAC2 inhibition reverses the protumor phenotype of macrophages mediated by epigenetic modulation induced by the HDAC2-SP1 axis, indicating a therapeutic option to modify the immunosuppressive tumor microenvironment.