The histone lysine methyltransferase MLL1 regulates the activation and functional specialization of regulatory T cells

The activation and specialization of regulatory T cells (Tregs) are crucial for maintaining immune self-tolerance; however, the regulation of these processes by histone modifications is not fully understood. Here, we show that T cell-specific deletion of the lysine methyltransferase MLL1 results in a spontaneous lymphocyte proliferation phenotype in aged mice without disturbing the development of conventional T cells and Tregs. Treg-specific MLL1 ablation leads to a systemic autoimmune disease associated with Treg dysfunction. Moreover, RNA sequencing demonstrates that the induction of multiple genes involved in Treg activation, functional specialization, and tissue immigration is defective in MLL1-deficient Tregs. This dysregulation is associated with defects in H3K4 trimethylation at these genes' transcription start sites. Finally, using a T-bet fate-mapping mouse system, we determine that MLL1 is required to establish stable Th1-type Tregs. Thus, MLL1 is essential in optimal Treg function by providing a coordinated chromatin context for activation and specialization.

NADPH oxidase exerts a B cell-intrinsic contribution to lupus risk by modulating endosomal TLR signals

Genome-wide association studies in systemic lupus erythematosus (SLE) have linked loss-of-function mutations in phagocytic NADPH oxidase complex (NOX2) genes, including NCF1 and NCF2, to disease pathogenesis. The prevailing model holds that reduced NOX2 activity promotes SLE via defective efferocytosis, the immunologically silent clearance of apoptotic cells. Here, we describe a parallel B cell-intrinsic mechanism contributing to breaks in tolerance. In keeping with an important role for B cell Toll-like receptor (TLR) pathways in lupus pathogenesis, NOX2-deficient B cells exhibit enhanced signaling downstream of endosomal TLRs, increased humoral responses to nucleic acid-containing antigens, and the propensity toward humoral autoimmunity. Mechanistically, TLR-dependent NOX2 activation promotes LC3-mediated maturation of TLR-containing endosomes, resulting in signal termination. CRISPR-mediated disruption of NCF1 confirmed a direct role for NOX2 in regulating endosomal TLR signaling in primary human B cells. Together, these data highlight a new B cell-specific mechanism contributing to autoimmune risk in NCF1 and NCF2 variant carriers.

Antiviral memory B cells exhibit enhanced innate immune response facilitated by epigenetic memory

The long-lasting humoral immunity induced by viral infections or vaccinations depends on memory B cells with greatly increased affinity to viral antigens, which are evolved from germinal center (GC) responses. However, it is unclear whether antiviral memory B cells represent a distinct subset among the highly heterogeneous memory B cell population. Here, we examined memory B cells induced by a virus-mimicking antigen at both transcriptome and epigenetic levels and found unexpectedly that antiviral memory B cells exhibit an enhanced innate immune response, which appeared to be facilitated by the epigenetic memory that is established through the memory B cell development. In addition, T-bet is associated with the altered chromatin architecture and is required for the formation of the antiviral memory B cells. Thus, antiviral memory B cells are distinct from other GC-derived memory B cells in both physiological functions and epigenetic landmarks.

Activated PI3Kδ specifically perturbs mouse Treg homeostasis and function leading to immune dysregulation

Foxp3+ regulatory T cells (Treg) are required for maintaining immune tolerance and preventing systemic autoimmunity. PI3Kδ is required for normal Treg development and function. However, the impacts of dysregulated PI3Kδ signaling on Treg function remain incompletely understood. Here, we used a conditional mouse model of activated PI3Kδ syndrome (APDS) to investigate the role of altered PI3Kδ signaling specifically within the Treg compartment. Aged mice expressing a PIK3CD gain-of-function mutation (aPIK3CD) specifically within the Treg compartment exhibited weight loss and evidence for chronic inflammation as demonstrated by increased memory/effector CD4+ and CD8+ T cells with enhanced IFN-γ secretion, spontaneous germinal center responses and production of broad-spectrum autoantibodies. Intriguingly, aPIK3CD facilitated Treg precursor development within the thymus and an increase in peripheral Treg numbers. Peripheral Treg, however, exhibited an altered phenotype including increased PD1 expression and reduced competitive fitness. Consistent with these findings, Treg specific-aPIK3CD mice mounted an elevated humoral response following immunization with a T-cell dependent antigen, that correlated with a decrease in follicular Treg. Taken together, these findings demonstrate that an optimal threshold of PI3Kδ activity is critical for Treg homeostasis and function, suggesting that PI3Kδ signaling in Treg might be therapeutically targeted to either augment or inhibit immune responses.

B cell-intrinsic TLR7 signaling is required for neutralizing antibody responses to SARS-CoV-2 and pathogen-like COVID-19 vaccines

Toll-like receptor 7 (TLR7) triggers antiviral immune responses through its capacity to recognize single-stranded RNA. TLR7 loss-of-function mutants are associated with life-threatening pneumonia in severe COVID-19 patients. Whereas TLR7-driven innate induction of type I IFN appears central to control SARS-CoV2 virus spreading during the first days of infection, the impact of TLR7-deficiency on adaptive B-cell immunity is less clear. In the present study, we examined the role of TLR7 in the adaptive B cells response to various pathogen-like antigens (PLAs). We used inactivated SARS-CoV2 and a PLA-based COVID-19 vaccine candidate designed to mimic SARS-CoV2 with encapsulated bacterial ssRNA as TLR7 ligands and conjugated with the RBD of the SARS-CoV2 Spike protein. Upon repeated immunization with inactivated SARS-CoV2 or PLA COVID-19 vaccine, we show that Tlr7-deficiency abolished the germinal center (GC)-dependent production of RBD-specific class-switched IgG2b and IgG2c, and neutralizing antibodies to SARS-CoV2. We also provide evidence for a non-redundant role for B-cell-intrinsic TLR7 in the promotion of RBD-specific IgG2b/IgG2c and memory B cells. Together, these data demonstrate that the GC reaction and class-switch recombination to the Myd88-dependent IgG2b/IgG2c in response to SARS-CoV2 or PLAs is strictly dependent on cell-intrinsic activation of TLR7 in B cells.

The splicing isoform Foxp3Δ2 differentially regulates tTreg and pTreg homeostasis

Foxp3 is the master transcription factor for regulatory T cells (Tregs). Alternative splicing of human Foxp3 results in the expression of two isoforms: the full length and an exon 2-deleted protein. Here, AlphaFold2 predictions and in vitro experiments demonstrate that the N-terminal domain of Foxp3 inhibits DNA binding by moving toward the C terminus and that this movement is mediated by exon 2. Consequently, we find that Foxp3Δ2-bearing thymus-derived Tregs (tTregs) in the peripheral lymphoid organ are less sensitive to T cell receptor (TCR) stimulation due to the enhanced binding of Foxp3Δ2 to the Batf promoter and are hyporesponsive to interleukin-2 (IL-2). In contrast, among RORγt+ peripherally induced Tregs (pTregs) in the large intestine, Foxp3Δ2 pTregs express many more RORγt-related genes, conferring a competitive advantage. Together, our results reveal that alternative splicing of exon 2 generates an active form of Foxp3, which plays a differential role in regulating tTreg and pTreg homeostasis.

The Crohn Disease-associated ATG16L1T300A polymorphism regulates inflammatory responses by modulating TLR- and NLR-mediated signaling

The mechanisms by which the ATG16L1^T300A polymorphism affects cell function and causes an increased risk for the development of Crohn disease remain incompletely understood. Here we report that healthy individuals and mice bearing this polymorphism, even as heterozygotes, manifest enhanced TLR, and NLR cytokine and chemokine responses due to increased activation of NFKB. We elucidated the mechanism of the NFKB abnormality and found that in the ATG16L1^T300A cell, there is enhanced polyubiquitination of TRAF6 or RIPK2 resulting from the accumulation of SQSTM1/p62. Indeed, knockout of Sqstm1 in autophagy-deficient cells almost completely normalized TRAF6 or RIPK2 polyubiquitination and NFKB activation in these cells. Thus, by identifying that autophagy is a pathway-intrinsic homeostatic mechanism that restricts excessive TLR- or NLR-mediated inflammatory signaling, our findings shed new light on how the ATG16L1^T300A polymorphism sets the stage for the occurrence of Crohn disease.Abbreviations: 3-MA: 3-methyladenine; ATG16L1: autophagy related 16 like 1; ATG7: autophagy related 7; BMDM: bone marrow-derived macrophage; CD: Crohn disease; CXCL: C-X-C motif chemokine ligand; IBD: inflammatory bowel disease; iBMDM: immortalized mouse BMDM; IL1B/IL-1β: interleukin 1 beta; IL6: interleukin 6; KI: knockin; KO: knockout; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; LPS: lipopolysaccharide; MDP: muramyl dipeptide; MEF: mouse embryonic fibroblast; NFKB/NF-κB: nuclear factor kappa B; NFKBIA/IKBA: NFKB inhibitor alpha; NLR: NOD-like receptor; NOD: nucleotide-binding oligomerization domain containing; RIPK2: receptor interacting serine/threonine kinase 2; SNP: single nucleotide polymorphism; SQSTM1/p62: sequestosome 1; TLR: toll like receptor; TNF/TNF-α: tumor necrosis factor; TRAF6: TNF receptor associated factor 6; Ub: ubiquitin; WT: wild type.

Apolipoprotein E mediates cell resistance to influenza virus infection

Viruses exploit host cell machinery to support their replication. Defining the cellular proteins and processes required for a virus during infection is crucial to understanding the mechanisms of virally induced disease and designing host-directed therapeutics. Here, we perform a genome-wide CRISPR-Cas9-based screening in lung epithelial cells infected with the PR/8/NS1-GFP virus and use GFP^hi cell as a unique screening marker to identify host factors that inhibit influenza A virus (IAV) infection. We discovered that APOE affects influenza virus infection both in vitro and in vivo. Cell deficiency in APOE conferred substantially increased susceptibility to IAV; mice deficient in APOE manifested more severe lung pathology, increased virus load, and decreased survival rate. Mechanistically, lack of cell-produced APOE results in impaired cell cholesterol homeostasis, enhancing influenza virus attachment. Thus, we identified a previously unrecognized role of APOE in restraining IAV infection.

Dysregulation of Innate and Adaptive Immune Responses in Asymptomatic SARS-CoV-2 Infection with Delayed Viral Clearance

Asymptomatic infection with SARS-CoV-2 is a major concern in the control of the COVID-19 pandemic. Many questions concerning asymptomatic infection remain to be answered, for example, what are the differences in infectivity and the immune response between asymptomatic and symptomatic infections? In this study, based on a cohort established by the Wuchang District Health Bureau of Wuhan in the early stage of the COVID-19 pandemic in Wuhan in 2019, we conducted a comprehensive analysis of the clinical, virological, immunological, and epidemiological data of asymptomatic infections. The major findings of this study included: 1) the asymptomatic cohort enrolled this study exhibited low-grade but recurrent activity of viral replication; 2) despite a lack of overt clinical symptoms, asymptomatic infections exhibited ongoing innate and adaptive immune responses; 3) however, the immune response from asymptomatic infections was not activated adequately, which may lead to delayed viral clearance. Given the fragile equilibrium between viral infection and host immunity, and the delayed viral clearance in asymptomatic individuals, close viral monitoring should be scheduled, and therapeutic intervention may be needed.

[Relationship between white matter lesions and theresponse of cerebral spinal fluid tap test and clinical features in the patients with idiopathic normal pressure hydrocephalus]

Objective: To explore the relationship between white matter lesions and clinical features and response of cerebral spinal fluid (CSF) tap test in patients with idiopathic normal pressure hydrocephalus(iNPH). Methods: Possible iNPH patients were enrolled from outpatients and inpatients in Peking Union Medical College Hospital between 2014 and 2019. All patients underwent detailed neuropsychological and walking assessments, CSF tap test, as well as head magnetic resonance imaging. The Fazekas score of white matter lesions, the fractional anisotropy (FA)and mean diffusivity (MD) values of regions of interest by means ofdiffusion tensor imaging (DTI) were compared between CSF tap test positive and negative response groups. The correlation between DTI parameters and clinical characteristics was analyzed. Results: Forty-three patients (29 male and 14 female, age range: 52-79 years] wererecruited.Compared with the negative group, patients in the positive group tended to have higher Fazekas score of periventricular white matter(U=108.00, P=0.03), higher MD value of the region near anterior horn of left lateral ventricles[(1.14±0.27)×10^-9mm²/s vs (0.85±0.08) ×10^-9mm²/s, P=0.003], lower FA value of the region near anterior horn of the right lateral ventricles[(0.20±0.07)vs(0.27±0.09), P=0.058], and higher MD value near the posterior horn of right lateral ventricle [(1.17±0.34)×10^-9mm²/s vs (0.95±0.01)×10^-9mm²/s, P=0.003]. FA and MD were significantly correlated with motor function, cognitive and functional scores, and iNPH grading scale (iNPHGS) scores(all P<0.05). Conclusions: The white matter lesions might be one of the pathogeneses of lNPH and apathological changewhich can be reversed by CSF drainage. More white matter lesions should not be the contraindication of CSF drainage surgery.

Activated PI3Kδ signals compromise plasma cell survival via limiting autophagy and increasing ER stress

While phosphatidylinositide 3-kinase delta (PI3Kδ) plays a critical role in humoral immunity, the requirement for PI3Kδ signaling in plasma cells remains poorly understood. Here, we used a conditional mouse model of activated PI3Kδ syndrome (APDS), to interrogate the function of PI3Kδ in plasma cell biology. Mice expressing a PIK3CD gain-of-function mutation (aPIK3CD) in B cells generated increased numbers of memory B cells and mounted an enhanced secondary response but exhibited a rapid decay of antibody levels over time. Consistent with these findings, aPIK3CD expression markedly impaired plasma cell generation, and expression of aPIK3CD intrinsically in plasma cells was sufficient to diminish humoral responses. Mechanistically, aPIK3CD disrupted ER proteostasis and autophagy, which led to increased plasma cell death. Notably, this defect was driven primarily by elevated mTORC1 signaling and modulated by treatment with PI3Kδ-specific inhibitors. Our findings establish an essential role for PI3Kδ in plasma cell homeostasis and suggest that modulating PI3Kδ activity may be useful for promoting and/or thwarting specific immune responses.

Quantum transfer through small networks coupled to phonons: Effects of topology versus phonons

Particle or energy transfer through quantum networks is determined by network topology and couplings to environments. This study examines the combined effect of topology and external couplings on the efficiency of directional quantum transfer through quantum networks. We consider a microscopic model of qubit networks coupled to external vibrations by Holstein and Peierls couplings. By treating the positions of the network sites and the site-dependent phonon frequencies as independent variables, we determine the Hamiltonian parameters corresponding to minimum transfer time by Bayesian optimization. The results show that Holstein couplings may accelerate transfer through suboptimal network configurations but cannot accelerate quantum dynamics beyond the limit of the transfer time in an optimal phonon-free configuration. By contrast, Peierls couplings distort the optimal networks to accelerate quantum transfer through configurations with less than six sites. However, the speed-up offered by Peierls couplings decreases with the network size and disappears for networks with more than seven sites. For networks with seven sites or more, Peierls couplings distort the optimal network configurations and change the mechanism of quantum transfer but do not affect the lower limit of the transfer time. The machine-learning approach demonstrated here can be applied to determine quantum speed limits in other applications.

A pathogen-like antigen-based vaccine confers immune protection against SARS-CoV-2 in non-human primates

Activation of nucleic acid sensing Toll-like receptors (TLRs) in B cells is involved in antiviral responses by promoting B cell activation and germinal center responses. In order to take advantage of this natural pathway for vaccine development, synthetic pathogen-like antigens (PLAs) constructed of multivalent antigens with encapsulated TLR ligands can be used to activate B cell antigen receptors and TLRs in a synergistic manner. Here we report a PLA-based coronavirus disease 2019 (COVID-19) vaccine candidate designed by combining a phage-derived virus-like particle carrying bacterial RNA as TLR ligands with the receptor-binding domain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) S protein as the target antigen. This PLA-based vaccine candidate induces robust neutralizing antibodies in both mice and non-human primates (NHPs). Using a NHP infection model, we demonstrate that the viral clearance is accelerated in vaccinated animals. In addition, the PLA-based vaccine induces a T helper 1 (Th1)-oriented response and a durable memory, supporting its potential for further clinical development.

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AP205-RBD elicits neutralizing antibodies against SARS-CoV-2 in mice and macaques

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AP205-RBD induces Th1-oriented immune response and durable memory

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Vaccination of AP205-RBD accelerates viral clearance in infected macaques

Cutting Edge: A Threshold of B Cell Costimulatory Signals Is Required for Spontaneous Germinal Center Formation in Autoimmunity

Cognate interactions between autoreactive B and T cells promote systemic lupus erythematosus pathogenesis by inter alia facilitating spontaneous germinal center (GC) formation. Whereas both myeloid and B cell APCs express B7 ligands (CD80 and CD86), the prevailing model holds that dendritic cell costimulation is sufficient for CD28-dependent T cell activation. In this study, we report that B cell-intrinsic CD80/CD86 deletion unexpectedly abrogates GCs in murine lupus. Interestingly, absent GCs differentially impacted serum autoantibodies. In keeping with distinct extrafollicular and GC activation pathways driving lupus autoantibodies, lack of GCs correlated with loss of RNA-associated autoantibodies but preserved anti-dsDNA and connective tissue autoantibody titers. Strikingly, even heterozygous B cell CD80/CD86 deletion was sufficient to prevent autoimmune GCs and RNA-associated autoantibodies. Together, these findings identify a key mechanism whereby B cells promote lupus pathogenesis by providing a threshold of costimulatory signals required for autoreactive T cell activation.

[Early outcome of valve sparing aortic root replacement with partial upper sternotomy]

Objective: To examine the early outcome of valve sparing aortic root replacement with reimplantation technique (David procedure) with partial upper sternotomy. Methods: From April 2016 to April 2020, 31 patients underwent valve sparing aortic root replacement under partial upper sternotomy at Vascular Surgery Center, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College. There were 28 males and 3 females, aging (44±13) years (range: 11 to 65 years). Preoperative aortic regurgitation was found greater than moderate in 15 patients, moderate in 6 patients and less than moderate in 10 patients. The diameter of aortic annulus was (26±3) mm (range: 21 to 34 mm), the diameter of aortic sinus was (51±6) mm (range: 41 to 68 mm), the diameter of ascending aorta was (43±8) mm (range: 26 to 62 mm). The preoperative ejection fraction was (65±4) % (range: 59% to 72%) and left ventricular end-diastolic diameter was (55±6) mm (range: 42 to 68 mm). All cases were treated with David Ⅰ procedure, including simple David procedure in 26 patients, David+ascending aorta and partial aortic arch replacement in 3 patients, David+thoracic endovascular aortic repair in 1 patient, David+stent elephant trunk implantation in 1 patient. Results: The operation time, cardiopulmonary bypass time and aortic cross-clamping time were (330±58) minutes (range: 214 to 481 minutes), (138±23) minutes (range: 106 to 192 minutes) and (108±17) minutes (range: 82 to 154 minutes), respectively. There were no death and serious complications (stroke, myocardial infarction, renal insufficiency, severe infection, etc.). The postoperative drainage volume within 24 hours was (314±145) ml (range: 130 to 830 ml). The intubation time was (14±3) hours (range: 8 to 21 hours), and the ICU time was (M(Q_R)) 2.1(1.5) days (range: 1.0 to 5.0 days). Eight patients had no blood transfusion, the proportion of red blood cell use was 9.7% (3/31), plasma use was 22.6% (7/31), and platelet use was 71.0% (22/31). The postoperative left ventricular ejection fraction was (62±4)% (range: 54% to 69%), and left ventricular end-diastolic diameter was (48±4) mm (range: 39 to 56 mm). After operation, aortic regurgitation was significantly improved, with no more than moderate regurgitation, small to moderate regurgitation in 3 patients, minor regurgitation in 3 patients, micro regurgitation in 12 patients and no regurgitation in 13 patients. The follow-up period was 3.5(6.1) months (range: 2.0 to 39.0 months). Echocardiographic follow-up data were obtained in 26 cases, including moderate regurgitation in 1 patient, small to moderate regurgitation in 9 patients, minor regurgitation in 5 patients, micro regurgitation in 6 patients and no regurgitation in 5 patients. There were no major adverse cardiovascular events and aortic events during the follow-up period. No patient was reoperated for aortic regurgitation. Conclusion: Valve sparing aortic root replacement under partial upper sternotomy is safe and feasible, and the early result is satisfactory.

Population-based evaluation of the risk factors and prognosis among renal cell carcinoma patients with initially diagnosed lung metastases

OBJECTIVES

To evaluate risk factors and prognosis of lung metastases in patients with renal cell carcinoma (RCC) based on the Surveillance, Epidemiology, and End Results (SEER) database.

METHODS

56,617 patients with RCC were selected from the SEER database. Based on univariate and multivariate logistic regression, the risk factors for developing lung metastases were derived. 2906 patients were initially diagnosed with lung metastases, and then were used to research the prognostic factors. Multivariable Cox regression analyses were performed for the prediction of cancer-specific mortality.

RESULTS

In total, 2906 RCC patients were initially diagnosed with lung metastases. The prevalence of lung metastases in RCC was approximately 5% with poor survival. Aging, male, other race (American Indian/AK native, Asian Pacific islander) uninsured status, bilateral tumor, collecting duct, higher T stage, local lymph node metastases, higher tumor grade, and evidence of other distant metastases were significantly associated with developing lung metastases at diagnosis. Age >70 years-old, black, female, bilateral tumor, T4 stage, higher tumor grade, local lymph node metastases, collecting duct, and evidence of bone, liver, or brain metastases were related to higher risk of mortality. Blacks and female have lower odds of developing lung metastases at the time of diagnosis both in crude and adjusted logistic regression. Meanwhile, blacks and female showed higher risk of mortality compared with whites and male in Cox regression analyses.

CONCLUSION

Several factors related to the development and prognosis of lung metastases were revealed, especially black people and female gender have lower risk of developing lung metastatic RCC at initial diagnosis but have higher risk of mortality. These may provide preventive guidelines for the screening and treatment of lung metastases in patients with renal cell carcinoma.

Diverse bacterial profile in extraradicular biofilms and periradicular lesions associated with persistent apical periodontitis

AIM

To characterize the bacterial community present in the extraradicular biofilm and periradicular lesions associated with persistent apical periodontitis.

METHODOLOGY

Eighteen adult patients who presented with persistent periradicular lesions after root canal treatment and scheduled for endodontic surgery were selected. During surgery, extraradicular samples of biofilms and periradicular lesions were collected. Ten pairs of periradicular lesions and extraradicular biofilm samples were randomly selected for ribosomal 16S rRNA cloning and sequencing. A Wilcoxon's rank-sum test was used to compare total bacterial counts and the levels of individual genera and species between the two groups (P < 0.05).

RESULTS

Overall, seventy-three phylotypes belonging to six different phyla were identified from 1000 sequenced clones. Mogibacterium timidum, Streptococcus intermedius and Enterococcus faecalis predominated in both extraradicular biofilm and periapical lesions. Propionibacterium propionicus, Abiotrophia adiacens, Peptostreptococcus prevotii, Campylobacter gracilis and Pseudomonas aeruginosa were found in significantly higher levels in the extraradicular biofilm than periapical lesions, whilst Parvimonas micra and Atopobium rimae were more abundant in periapical lesions (P < 0.05).

CONCLUSIONS

The microbial profile of extraradicular biofilms differed from periapical lesions, indicating the presence of diverse bacterial populations in these regions. Several genera and species were significantly associated with the formation of extraradicular biofilms.

[Expression of lncRNA MIR210HG in preeclampsia placental tissue and its functional analysis]

Objective: To investigate the differential expression of long non-coding RNA (lncRNA) in placental tissues of women with preeclampsia (PE) and the effect of MIR210HG on the biological function of HTR8/SVneo cells. Methods: A total of 39 cases of PE women (PE group) and 39 cases of normal pregnant women (CTL group) admitted to the Affiliated Hospital of Qingdao University from July 2018 to July 2019 were collected. (1) Transcriptome sequencing (RNA-seq) was used to analyze the differentially expressed lncRNAs in the placental tissues of the two groups. (2) The expression level of MIR210HG, one of the differentially expressed lncRNAs, in the placental tissues of the two groups was detected by real-time quantitative PCR. And the correlations between the expression level of MIR210HG and systolic blood pressure, diastolic blood pressure and neonatal birth weight were analyzed. (3) The constructed small interfering RNA and negative control (NC) RNA were transfected into the HTR8/SVneo cells. The cells were divided into MIR210HG knockdown (KD) group and NC group. The effects of living cell counting (CCK-8) and transwell assay on the proliferation and migration of HTR8/SVneo cells were detected. (4) RNA interacting with MIR210HG was predicted using the Encyclopedia of RNA Interactomes (ENCORI) database. Gene Ontology (GO) functional annotation, Kyoto Encyclopedia of Gene and Genomes (KEGG) and BioCarta pathway enrichment analysis were performed. Results: (1) A total of 26 significantly differentially expressed lncRNAs were found by RNA-seq, among which 21 lncRNAs were up-regulated and 5 lncRNAs were down-regulated. (2) The relative expression level of MIR210HG in the PE group was significantly higher than that in the CTL group (9.30±1.90 and 1.10±0.20, respectively; t=4.425, P<0.01). The relative expression level of MIR210HG had positive linear correlation with systolic blood pressure (r²=0.234, P<0.05) and diastolic blood pressure (r²=0.190, P<0.05), but had a negative linear correlation with newborn birth weight (r²=0.157, P<0.05). (3) Compared with the NC group, the proliferation and migration ability of HTR8/SVneo cells in the KD group were increased (all P<0.05). (4) A total of 38 RNAs that might interact with MIR210HG were predicted by ENCORI database. GO functional annotation analysis showed that MIR210HG might be involved in the functions of 27 pathways, including the regulation of production of molecular mediator of immune response, etc; KEGG pathway analysis showed that MIR210HG might be involved in the function of 8 pathways including allograft rejection, etc; Biocarta pathway analysis showed that MIR210HG may be involved in the functions of 8 pathways, including the eukaryotic initiation factor (eIF) pathway, etc. Conclusion: The expression of MIR210HG is up-regulated in the placental tissue of PE women, and MIR210HG might be a regulator of the biological behavior of trophoblast cells.

Population-based evaluation of the risk factors and prognosis among renal cell carcinoma patients with initially diagnosed lung metastases

OBJECTIVES

To evaluate risk factors and prognosis of lung metastases in patients with renal cell carcinoma (RCC) based on the Surveillance, Epidemiology, and End Results (SEER) database.

METHODS

56, 617 patients with RCC were selected from the SEER database. Based on univariate and multivariate logistic regression, the risk factors for developing lung metastases were derived. 2, 906 patients were initially diagnosed with lung metastases, and then were used to research the prognostic factors. Multivariable Cox regression analyses were performed for the prediction of cancer-specific mortality.

RESULTS

In total, 2,906 RCC patients were initially diagnosed with lung metastases. The prevalence of lung metastases in RCC was approximately 5% with poor survival. Aging, male, other race (American Indian /AK native, Asian Pacific islander) uninsured status, bilateral tumor, collecting duct, higher T stage, local lymph node metastases, higher tumor grade, and evidence of other distant metastases were significantly associated with developing lung metastases at diagnosis. Age > 70 years-old, black, female, bilateral tumor, T4 stage, higher tumor grade, local lymph node metastases, collecting duct, and evidence of bone, liver, or brain metastases were related to higher risk of mortality. Blacks and female have lower odds of developing lung metastases at the time of diagnosis both in crude and adjusted logistic regression. Meanwhile, blacks and female showed higher risk of mortality compared with whites and male in Cox regression analyses.

CONCLUSION

Several factors related to the development and prognosis of lung metastases were revealed, especially black people and female gender have lower risk of developing lung metastatic RCC at initial diagnosis but have higher risk of mortality. These may provide preventive guidelines for the screening and treatment of lung metastases in patients with renal cell carcinoma.

Tumor-derived exosomal miR-103a-2-5p facilitates esophageal squamous cell carcinoma cell proliferation and migration

OBJECTIVE

This study aimed to identify the different expression of microRNAs (miRNAs) in the plasma derived exosomes of patients with esophageal squamous cell carcinoma (ESCC).

PATIENTS AND METHODS

A total of 9 patients with ESCC and 9 patients with benign diseases were involved. miRNA sequencing was performed to screen differential expression of microRNAs in plasma exosomes between patients with ESCC and controls. The function of miRNA on proliferation and migration abilities was determined by CCK-8 analysis, wound scratch and transwell test. Predicted target genes were screened by databases and confirmed by RT-qPCR.

RESULTS

We identified a total of 10 miRNAs (7 upregulated and 3 downregulated) that were differentially expressed in plasma exosomes between patients with ESCC and control patients (fold change, FC ≥ 2.0 or ≤ -2.0, p ≤ 0.05) by miRNA sequencing. Ten miRNAs were detected by qRT-PCR to verify the results of the miRNA sequencing. MiR-103a-2-5p demonstrated the most significant differential expression in both exosomes of ESCC cell lines and plasma of patients as compared with control patients and was therefore selected for subsequent functional experiments. Overexpression of miR-103a-2-5p promoted proliferation and migration in TE-1 cells, whereas inhibition of miR-103a-2-5p suppressed proliferation and migration in KYSE-150 cells. Exosomes extracted from the cells transfected with miR-103a-2-5p mimics significantly increased the proliferation and migration of two ESCC cell lines. Two genes, CDH11 and NR3C1 were identified as predicted targets of miR-103a-2-5p by the bioinformatics tools TargetScan, MiRanda, and mirDIP and RT-qPCR.

CONCLUSIONS

Our results shed light on how exosomal miR-103a-2-5p can promote proliferation and migration of ESCC cells and may represent a potential target for ESCC therapies.

Noc4L-Mediated Ribosome Biogenesis Controls Activation of Regulatory and Conventional T Cells

Regulatory T cell (Treg) activation is crucial for maintaining self-tolerance, but the translational regulation of this process is still poorly understood. Although ribosome biogenesis is considered a housekeeping process, emerging evidence supports the hypothesis that ribosome biogenesis can selectively regulate protein synthesis by tuning translation. Here, we focused on the ribosome biogenesis factor Noc4L, based on the observations that Noc4L is highly expressed in activated Tregs. Conditional Noc4L knockout in Tregs resulted in a lethal autoimmune phenotype resembling Treg-deficient scurfy mice. Interestingly, the Noc4L defect did not globally affect overall protein translation in Tregs but was selectively detrimental to the expression of mRNAs related to Treg activation. These results demonstrate the critical role of Noc4L-mediated ribosome biogenesis in controlling the activation of Tregs and maintaining immune tolerance.

FAM83H overexpression predicts worse prognosis and correlates with less CD8+ T cells infiltration and Ras-PI3K-Akt-mTOR signaling pathway in pancreatic cancer

BACKGROUND

Family with sequence similarity 83 members H (FAM83H) is one member of Family with sequence similarity 83 (FAM83) family, which possess oncogenic properties in several types of cancer. However, the potential function of FAM83H in pancreatic cancer (PC) still remain unknown.

AIM

This study aims to explore the role of FAM83H during pancreatic carcinogenesis and the regulation of immune infiltration in PC.

METHODS

In the current study, the clinical significance and potential biological of FAM83H were evaluated by bioinformatics analysis. Possible associations between FAM83H expression and tumor immunity were analyzed using ESTIMATE algorithm and single-sample gene set enrichment analysis (ssGSEA).

RESULTS

FAM83H expression was significantly upregulated in tumor tissues, and positively associated with higher histologic grade, tumor recurrence, and worse prognosis. FAM83H overexpression is notably associated with KRAS activation. And functional enrichment analysis demonstrated that FAM83H may be involved in positive regulation of cell proliferation and migration, Ras protein signal transduction, regulation of cell-matrix adhesion, epithelial to mesenchymal transition (EMT), TGF-β receptor signaling in EMT, and activated NOTCH transmits signal to the nucleus. ESTIMATE algorithm and ssGSEA demonstrated that FAM83H overexpression suppressed the infiltration and antitumor activity of tumor-infiltrating lymphocytes (TILs), especially for CD8⁺ T cells. Besides, FAM83H overexpression significantly correlated with low expression of TIL-related gene markers (e.g. CD8A, CD8B, CD2, CD3D, and CD3E).

CONCLUSION

The study suggests that FAM83H overexpression predicts poor prognosis and correlates with less CD8⁺ T cells infiltration and Ras-PI3K-Akt-mTOR signaling pathway in PC.

Serine Phosphorylation of the STAT1 Transactivation Domain Promotes Autoreactive B Cell and Systemic Autoimmunity Development

Although STAT1 tyrosine-701 phosphorylation (designated STAT1-pY701) is indispensable for STAT1 function, the requirement for STAT1 serine-727 phosphorylation (designated STAT1-pS727) during systemic autoimmune and antipathogen responses remains unclear. Using autoimmune-prone B6.Sle1b mice expressing a STAT1-S727A mutant in which serine is replaced by alanine, we report in this study that STAT1-pS727 promotes autoimmune Ab-forming cell (AFC) and germinal center (GC) responses, driving autoantibody production and systemic lupus erythematosus (SLE) development. In contrast, STAT1-pS727 is not required for GC, T follicular helper cell (Tfh), and Ab responses to various foreign Ags, including pathogens. STAT1-pS727 is also not required for gut microbiota and dietary Ag-driven GC and Tfh responses in B6.Sle1b mice. By generating B cell-specific bone marrow chimeras, we demonstrate that STAT1-pS727 plays an important B cell-intrinsic role in promoting autoimmune AFC, GC, and Tfh responses, leading to SLE-associated autoantibody production. Our analysis of the TLR7-accelerated B6.Sle1b.Yaa SLE disease model expressing a STAT1-S727A mutant reveals STAT1-pS727-mediated regulation of autoimmune AFC and GC responses and lupus nephritis development. Together, we identify previously unrecognized differential regulation of systemic autoimmune and antipathogen responses by STAT1-pS727. Our data implicate STAT1-pS727 as a therapeutic target for SLE without overtly affecting STAT1-mediated protection against pathogenic infections.

Serine phosphorylation of the STAT1 transactivation domain promotes autoreactive B cell and systemic autoimmunity development

Although STAT1 tyrosine-701 phosphorylation (STAT1-pY701) is indispensable for STAT1 function, the requirement for STAT1 serine-727 phosphorylation (STAT1-pS727) during autoimmune and anti-pathogen responses remains unclear. Here we report that STAT1-pS727 promotes autoimmune antibody-forming cell (AFC) and germinal center (GC) responses, driving systemic lupus erythematosus (SLE) development. STAT1-pS727, however, is not required for GC and antibody responses to foreign-antigens including pathogens or gut microbiota. STAT1-pS727 plays an important B cell-intrinsic role in driving autoimmunity. Transcriptomic analysis of B cells from TLR7-accelerated SLE-prone mice reveals STAT1-pS727-mediated gene regulation of cellular pathways known to be involved in autoimmune GC and AFC responses. Mechanistically, TLR7 activation in B cells induces STAT1-pS727 and during autoimmune responses TLR7 signaling converges with IFNγ-STAT1 signaling in B cells by recruiting STAT1 into the MyD88 signaling complex. Together, we identify previously unappreciated differential regulation of autoimmune and anti-pathogen responses by STAT1-pS727, and implicate STAT1-pS727 as a therapeutic target for SLE.

The role of B cell antigen presentation in the initiation of CD4+ T cell response

B cells have been known for their ability to present antigens to T cells for almost 40 years. However, the precise roles of B cell antigen presentation in various immune responses are not completely understood. The term "professional" antigen-presenting cells (APCs) was proposed to distinguish APCs that are required for initiating the immune responses from those use antigen presentation to enhance their own effector functions. Unlike dendritic cells, which are defined as professional APCs for their well-established functions in activating naive T cells, B cells have been shown in the past to mostly present antigens to activated CD4+ T cells mainly to seek help from T helper cells. However, recent evidence suggested that B cells can act as professional APCs under infectious conditions or conditions mimicking viral infections. B cell antigen receptors (BCRs) and the innate receptor Toll-like receptors are activated synergistically in response to pathogens or virus-like particles, under which conditions B cells are not only potent but also the predominant APCs to turn naive CD4+ T cells into T follicular helper cells. The discovery of B cells as professional APCs to initiate CD4+ T cell response provides a new insight for both autoimmune diseases and vaccine development.

Mismatch of cognition and neural networks in asymptomatic middle cerebral artery steno-occlusive disease

BACKGROUND AND PURPOSE

The role of intracranial steno-occlusive disease in cognitive impairment and dementia is unclear and has not been well studied.

METHODS

A total of 32 consecutive patients (13 males, aged 54 ± 12 years) with asymptomatic steno-occlusive middle cerebral artery (MCA) disease, defined as >70% stenosis on maximum intensity projection images or a complete signal loss of MCA trunk on magnetic resonance angiography, and 20 age- and education-matched normal controls (12 males, 60 ± 8 years old) were compared for neuropsychological performance, gray matter volume and neural network analysis.

RESULTS

The patient group did not show a significant decrease in gray matter volume or cognitive tests except for their performance on the grooved pegboard test. However, graph analysis of resting-state functional magnetic resonance imaging showed significant decreases in network strength, global efficiency and the clustering coefficient, as well as a longer characteristic path length (P < 0.05). The diffusive decrease pattern was particularly located in interhemispheric connectivity and there was no compensatory hyperconnectivity in any brain regions.

CONCLUSION

In asymptomatic steno-occlusive MCA disease, cognition and neural network changes are mismatched and have underlying pathophysiological mechanisms that are different from those of neurodegenerative disease.

Thrombocytopenia Impairs Host Defense Against Burkholderia pseudomallei (Melioidosis)

Background

Infection with the gram-negative bacillus Burkholderia pseudomallei (melioidosis) is an important cause of pneumosepsis in Southeast Asia and has a mortality of up to 40%. We aimed to assess the role of platelets in the host response against B. pseudomallei infection.

Methods

Association between platelet counts and mortality was determined in 1160 patients with culture-proven melioidosis. Mice treated with (low- or high-dose) platelet-depleting antibody were inoculated intranasally with B. pseudomallei and killed. Additional studies using functional glycoprotein Ibα-deficient mice were conducted.

Results

Thrombocytopenia was present in 31% of patients at admission and predicted mortality in melioidosis patients even after adjustment for confounders. In our murine-melioidosis model, platelet counts decreased, and mice treated with a platelet-depleting antibody showed enhanced mortality and higher bacterial loads compared to mice with normal platelet counts. Low platelet counts had a modest impact on early-pulmonary neutrophil influx. Reminiscent of their role in hemostasis, platelet depletion impaired vascular integrity, resulting in early lung bleeding. Glycoprotein Ibα-deficient mice had reduced platelet counts during B. pseudomallei infection together with an impaired local host defense in the lung.

Conclusions

Thrombocytopenia predicts mortality in melioidosis patients and, during experimental melioidosis, platelets play a protective role in both innate immunity and vascular integrity.

Functional Characterization of CD11c+ Age-Associated B Cells as Memory B Cells

Age-associated B cells (ABCs) are a unique subset of B cells defined by surface CD11b and CD11c expression. Although ABC expansion has been observed in both human and animal studies in the setting of advanced age, during humoral autoimmunity and following viral infection, the functional properties of this cellular subset remain incompletely defined. In the current study, we demonstrate that ABCs fulfill the criteria for memory B cells (MBCs), based on evidence of Ag-dependent expansion and persistence in a state poised for rapid differentiation into Ab-secreting plasma cells during secondary responses. First, we show that a majority of ABCs are not actively cycling but exhibit an extensive replication history consistent with prior Ag engagement. Second, despite unswitched surface IgM expression, ABCs show evidence of activation-induced cytidine deaminase (AID)-dependent somatic hypermutation. Third, BCRs cloned from sorted ABCs exhibit broad autoreactivity and polyreactivity. Although the overall level of ABC self-reactivity was not increased relative to naive B cells, ABCs lacked features of functional anergy characteristic of autoreactive B cells. Fourth, ABCs express MBC surface markers consistent with being poised for rapid plasma cell differentiation during recall responses. Finally, in a murine model of viral infection, adoptively transferred CD11c⁺ B cells rapidly differentiated into class-switched Ab-secreting cells upon Ag rechallenge. In summary, we phenotypically and functionally characterize ABCs as IgM-expressing MBCs, findings that together implicate ABCs in the pathogenesis of systemic autoimmunity.

Combined propidium monoazide pretreatment with high-throughput sequencing evaluated the bacterial diversity in chicken skin after thermal treatment

AIMS

The purpose of this experiment was to study the bacterial diversity and predominance of spoilage bacteria in chicken skin at different thermal treatment temperatures (60, 70, 80, 90, 100, 110, 120°C).

METHOD AND RESULTS

Bacteria in chicken skin was collected, then propidium monoazide treatment to remove the DNA of dead cell, total DNA was extracted by Tiandz Bacterial DNA Kit, and investigated by high-throughput sequencing of the v3/v4 regions of the 16S rDNA gene. A total of 796 008 high-quality bacterial sequences were obtained for assessing the microbial diversity of chicken skin from seven thermal treatment group and control group. The results showed that the bacterial diversity in chicken skin at 90°C was lowest. And Acinetobacter (25·88%), Clostridium (20·70%), Bacteroides (13·93%) and Myroides (13·13%) were the main flora at 25°C; The Clostridium was dominant genus of the samples heat-treated by 60, 70, 80 and 90°C, the proportion of this genus were up to 64·86, 77·42, 52·22 and 87·30% respectively. The Bacillus was the main flora of the samples heat-treated by 100, 110 and 120°C, and the relative percentages were 39·44, 79·61 and 45·96% respectively. In addition, high-temperature-resistant Serratia was found in chicken skin.

CONCLUSIONS

The study revealed that the relationship between thermal treatment temperature and bacterial diversity and dominant spoilage bacteria in chicken skin, which had a strong guiding significance for the control and prediction of micro-organisms in foods.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results of this paper could provide a theoretical basis for meat products containing chicken skin, including the safe use of chicken skin, determination of sterilization process parameters and selection of preservatives for compounding, which has strong practicality in China.

Bacillus licheniformis Zhengchangsheng® attenuates DSS-induced colitis and modulates the gut microbiota in mice

Human inflammatory bowel disease (IBD) and experimental colitis models in mice are associated with shifts in gut microbiota composition, and several probiotics are widely used to improve gastrointestinal health. Here, we investigated whether the probiotic Bacillus licheniformis Zhengchangsheng® (BL) ameliorates dextran sulphate sodium (DSS)-induced colitis through alteration of the gut microbiota. Experimental colitis was induced in BALB/C mice by dissolving 3% DSS in their drinking water for 7 days, which were gavaged with 0.2 ml phosphate-buffered saline or BL (3×107 cfu/ml) once a day. Administration of BL attenuated several effects of DSS-induced colitis, including weight loss, increased disease activity index, and disrupted intestinal barrier integrity. In addition, BL mitigated the reduction in faecal microbiota richness in DSS treated mice. Interestingly, BL was found to reduce the elevated circulating endotoxin level in mice with colitis by modulating the microbial composition of the microbiota, and this was highly associated with a proportional decrease in gut Bacteroidetes. Our results demonstrate that BL can attenuate DSS-induced colitis and provide valuable insight into microbiota interactions during IBD.

[Value of MRI in the pre-operative diagnosis and classification of oblique vaginal septum syndrome]

Objective: To explore the role of MRI in the pre-operative diagnosis and classification of oblique vaginal septum syndrome (OVSS) . Methods: A retrospective analysis of the clinical records and pre-operative MRI images of 19 patients with surgery proved OVSS was carried out. Two experienced radiologists reviewed the pre-operative pelvic MRI of the 19 patients in consensus blind to the surgery results. Characteristics including malformations of the uterus, cervix and vagina, the diagnosis of the disorder and classification were evaluated. Pre-operative MRI diagnosis and classification were correlated with surgical findings. Results: Mean age of onset of symptoms for the 19 patients was 15 years (ranged 9-25 years) , and mean age of menarche was 12 years. Ten patients suffered from dysmenorrhea or lower abdominal pain, 5 patients complained of vaginal discharge, 3 patients had a history of irregular menstruation, 1 patient suffered from primary infertility. All 19 patients showed uteri didelphys. Eighteen patients showed vaginal oblique septum.One patient showed cervical atresia.MRI was completely correlated with the surgery in the pre-operative diagnosis of OVSS. MRI classification was in line with surgery in 17 patients, including 9 patients with imperforate septum (typeⅠ) , 6 patients with perforate septum (type Ⅱ) , 1 patient with imperforate septum and cervical fistula (type Ⅲ) , and another one with cervical agenesis (type Ⅳ) . One case of type Ⅱ was misdiagnosed as type Ⅰ, another one of type Ⅰ was misdiagnosed as type Ⅲ. Pre-operative MRI classification was correlated with surgery in 17 out of 19 patients. Conclusion: Pre-operative MRI allows excellent manifestation and accurate diagnosis of OVSS, and could also facilitate the evaluation of the classification.

The RNA-binding protein ROD1/PTBP3 cotranscriptionally defines AID-loading sites to mediate antibody class switch in mammalian genomes

Activation-induced cytidine deaminase (AID) mediates class switching by binding to a small fraction of single-stranded DNA (ssDNA) to diversify the antibody repertoire. The precise mechanism for highly selective AID targeting in the genome has remained elusive. Here, we report an RNA-binding protein, ROD1 (also known as PTBP3), that is both required and sufficient to define AID-binding sites genome-wide in activated B cells. ROD1 interacts with AID via an ultraconserved loop, which proves to be critical for the recruitment of AID to ssDNA using bi-directionally transcribed nascent RNAs as stepping stones. Strikingly, AID-specific mutations identified in human patients with hyper-IgM syndrome type 2 (HIGM2) completely disrupt the AID interacting surface with ROD1, thereby abolishing the recruitment of AID to immunoglobulin (Ig) loci. Together, our results suggest that bi-directionally transcribed RNA traps the RNA-binding protein ROD1, which serves as a guiding system for AID to load onto specific genomic loci to induce DNA rearrangement during immune responses.

[Resting-state functional MRI studies of amyotrophic lateral sclerosis patients with various levels of cognitive impairment]

Objective: To characterize the brain functional changes of amyotrophic lateral sclerosis (ALS) patients with various levels of cognitive impairment as measured by resting-state functional MRI (RS-fMRI). Methods: From September 2013 to March 2017, a total of 55 patients diagnosed with ALS in Peking Union Medical College Hospital and 20 healthy controls (HCs) were included in this study, and all participants underwent neuropsychological assessments and diffusion tensor imaging scans. According to their cognitive performance, ALS patients were further subclassified into ALS with normal cognition (ALS-Cn, n=27), those with cognitive impairment (ALS-Ci, n=17) and ALS-FTD (n=11). Comparisons of fractional amplitude of low frequency fluctuation (fALFF) value and regional homogeneity (ReHo) value were conducted among the 4 subgroups. Results: The fALFF showed significant differences in bilateral frontal lobe, left temporal lobe and cingulate gyrus, (P<0.001, uncorrected) and the ReHo showed significant differences in left frontal lobe, right temporal lobe and left cingulate gyrus (P<0.001, FDR corrected). The differences mainly stemmed from that patients with ALS-FTD showed decreased fALFF and ReHo in these areas when compared to the other three groups, especially in relation to HCs, mainly locating in left prefrontal lobe and anterior cingulate cortex. The whole-brain comparisons of fALFF and ReHo between ALS-Ci, ALS-Cn and HCs revealed no significant difference (P<0.001, uncorrected). Conclusion: Hypoactivities are detected in extramotor areas in patients with ALS-FTD. RS-fMRI is helpful in investigating the pathophysiologic mechanism of cognitive impairment in ALS.

PTEN-Regulated AID Transcription in Germinal Center B Cells Is Essential for the Class-Switch Recombination and IgG Antibody Responses

Class-switch recombination (CSR) and somatic hypermutation (SHM) occur during the differentiation of germinal center B cells (GCBs). Activation-induced cytidine deaminase (AID) is responsible for both CSR and SHM in GCBs. Here, we show that ablation of PTEN through the Cγ1-Cre mediated recombination significantly influences the CSR and SHM responses. The GCs fail to produce the IgG1 B cells, the high affinity antibodies and nearly lost the dark zone (DZ) in Pten^fl/flCγ1^Cre/+ mice after immunization, suggesting the impaired GC structure. Further mechanistic investigations show that LPS- and interleukin-4 stimulation induced the transcription of Cγ1 in IgM-BCR expressing B cells, which efficiently disrupts PTEN transcription, results in the hyperphosphorylated AKT and FoxO1 and in turn the suppression of AID transcription. Additionally, the reduced transcription of PTEN and AID is also validated by investigating the IgM-BCR expressing GCBs from Pten^fl/flCγ1^Cre/+ mice upon immunization. In conclusion, PTEN regulated AID transcription in GCBs is essential for the CSR and IgG antibody responses.

B cell-derived IL-6 initiates spontaneous germinal center formation during systemic autoimmunity

Arkatkar et al. report that B cell–derived IL-6 is critical for T follicular helper cell differentiation, spontaneous germinal center formation, and class-switched autoantibody production during humoral autoimmunity.

Recent studies have identified critical roles for B cells in triggering autoimmune germinal centers (GCs) in systemic lupus erythematosus (SLE) and other disorders. The mechanisms whereby B cells facilitate loss of T cell tolerance, however, remain incompletely defined. Activated B cells produce interleukin 6 (IL-6), a proinflammatory cytokine that promotes T follicular helper (T_FH) cell differentiation. Although B cell IL-6 production correlates with disease severity in humoral autoimmunity, whether B cell–derived IL-6 is required to trigger autoimmune GCs has not, to our knowledge, been addressed. Here, we report the unexpected finding that a lack of B cell–derived IL-6 abrogates spontaneous GC formation in mouse SLE, resulting in loss of class-switched autoantibodies and protection from systemic autoimmunity. Mechanistically, B cell IL-6 production was enhanced by IFN-γ, consistent with the critical roles for B cell–intrinsic IFN-γ receptor signals in driving autoimmune GC formation. Together, these findings identify a key mechanism whereby B cells drive autoimmunity via local IL-6 production required for T_FH differentiation and autoimmune GC formation.

Epithelial Myeloid-Differentiation Factor 88 Is Dispensable during Klebsiella Pneumonia

Klebsiella pneumoniae is a common cause of pneumonia. Previous studies have documented an important role for Toll-like receptors (TLRs) expressed by myeloid cells in the recognition of K. pneumoniae and the initiation of a protective immune response. Lung epithelial cells also express TLRs and can participate in innate immune defense. The aim of this study was to examine the role of the common TLR adaptor protein myeloid-differentiation factor (MyD) 88 in lung epithelium during host defense against K. pneumoniae-induced pneumonia. To this end, we first crossed mice expressing cre recombinase under the control of the surfactant protein C (SftpCcre) or the club cell 10 kD (CC10cre) promoter with reporter mice to show that SftpCcre mice mainly express cre in type II alveolar cells, whereas CC10cre mice express cre almost exclusively in bronchiolar epithelial cells. We then generated mice with cell-targeted deletion of MyD88 in type II alveolar (SftpCcre-MyD88-lox) and bronchiolar epithelial (CC10cre-MyD88-lox) cells, and infected them with K. pneumoniae via the airways. Bacterial growth and dissemination were not affected by the loss of MyD88 in SftpCcre-MyD88-lox or CC10cre-MyD88-lox mice compared with control littermates. Furthermore, inflammatory responses induced by K. pneumoniae in the lung were not dependent on MyD88 expression in type II alveolar or bronchiolar epithelial cells. These results indicate that MyD88 expression in two distinct lung epithelial cell types does not contribute to host defense during pneumonia caused by a common human gram-negative pathogen.

Enhancement of THz generation by feedback-optimized wavefront manipulation

We apply active feedback optimization methods to pyroelectric measurements of a THz signal generated by four wave mixing in air using 1 mJ to 12 mJ, 35 fs laser pulses operating at 12 kHz repetition rate. A genetic algorithm, using the THz signal as a figure of merit, determines the voltage settings to a deformable mirror and results in up to a 6 fold improvement in the THz signal compared with settings optimized for the best focus. It is possible to optimize for different THz generation processes using this technique.