bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of Twitter in classroom attendance and participation in a Microbiology & Immunology course
Authors: Othman Tesneem , Royan Ayla , Fazal Nadeem 
Published: January 2023

Abstract
The use of social media in education has become increasingly prominent in recent years by educators in an attempt to improve students’ learning and to increase interaction in large classroom lectures. Among the popular social networking websites, Twitter is of particular interest due to its ease of use, micro blogging and hash tag capabilities. The objective of this study was to assess the use of Twitter in classroom attendance among professional first-year students. This study is distinguished by its focus on the pharmacy curricula, and among first year pharmacy students at CSU College of Pharmacy. All students enrolled in Microbiology and Immunology in the spring semester were included in the study. Students were permitted to use mobile devices in class and were recommended to create a Twitter account and add fellow colleagues and the course coordinator to participate in the study. Data from attendance was collected and analyzed according to the number of students that were present at the beginning of lecture, the number of students that were present until the end of lecture, the number of students that tweeted, the number of students that missed the tweet, and the number of students that tweeted their presence but were not actually in class. Since the study was voluntary, a total of 72 students signed a consent form to participate. An average of 59 students were present at the beginning and stayed until the end of lecture for the duration of the study. The analysis of variance (ANOVA) model was used to assess for differences in attendance at the beginning of class and at the end of class. This study demonstrates that the use of Twitter to take classroom attendance is more useful compared to traditional methods of roll call and sign-in sheets and announcements.
Subversion of macrophage autophagy and inflammatory pathways by Coxiella burnetii
Authors: Winchell Caylin G , Graham Joseph G. , Kurten Richard C , Voth Daniel E 
Published: January 2023

Abstract
Coxiella burnetii is the causative agent of human Q fever, a debilitating flu like illness that can progress to chronic disease presenting as endocarditis. After inhalation, C. burnetii is phagocytosed by alveolar macrophages and generates a lysosome-like replication niche known as the parasitophorous vacuole (PV). A type IV secretion system (T4SS) is required for generation of the PV and is one of the pathogen’s few known virulence factors. We previously showed that C. burnetii actively recruits autophagosomes to the PV using the T4SS, but does not alter macroautophagy. Interestingly, the cargo receptor p62 localizes to the PV in a T4SS-dependent manner and co-localizes with LC3. p62 and LC3 interact to select cargo for autophagy-mediated degradation, resulting in p62 degradation and LC3 recycling. In C. burnetii-infected macrophages, p62 is not degraded when cells are starved. We hypothesized that stabilization of p62 was due to activation of the NRF2-KEAP1 pathway, a cytoprotective response to oxidative stress and xenobiotics. Indeed, the NRF2-KEAP1 pathway was activated during infection as evidenced by translocation of NRF2 to the nucleus. A downstream target of the NRF2-KEAP1 pathway is NF-kB, and the role of this inflammatory signaling cascade in C. burnetii pathogenesis is unclear. However, previous studies showed differences in inflammasome activation when macrophages were infected with avirulent or virulent C. burnetii isolates. Therefore, we assessed NF-kB activation in alveolar macrophages infected by avirulent or virulent C. burnetii. Collectively, our studies highlight important host cell signaling pathways exploited by C. burnetii and differences in the innate immune response to differing pathotypes.
Accumulating necrotic cell debris and damaged mitochondria contribute to sepsis-like syndrome during late-phase tularemia.
Authors: Singh Anju , Periasamy Sivakumar , Rahman Tabassum , Ault Jeffrey G. , manella Carmen , Sellati Timothy J. 
Published: January 2023

Abstract
Infection with Francisella tularensis SchuS4 causes a severe pulmonary disease in mice, non-human primates, and patients known as tularemia. F. tularensis subverts host cell death programs to facilitate their unfettered replication within macrophages and other cell types, a common feature of early respiratory infection (≤ 72 h). The mechanism(s) by which the complex process of cell death is initiated remains incompletely-defined as does the impact of F. tularensis on mitochondria, the host cell’s organellar ‘canary in a coal mine’. Herein we reveal that host cells undergo Bax-dependent mitochondrial apoptosis via the intrinsic pathway. These events encompass: i) decreased mitochondrial membrane potential and consequent mitochondrial oncosis, ii) increased mitochondrial superoxide generation, and iii) release of damaged mitochondria and other damage-associated molecular patterns into the lung parenchyma, which contributes to a sepsis-like syndrome. Notably, host recognition of and response to accumulating necrotic cell debris elicits the TNF, IL-1β, IL-6, IL-12p70, and IFN-γ which are absent during early infection, but present during late-phase septic disease (≥ 72 h).
Helminth parasites and cancer-causing tumors condition human monocytes similarly: insights into parallel mechanisms of immune evasion
Authors: Narasimhan Prakash Babu , Akabas Leor , Huda Naureen , Sabzevari Helen , Hofmeister Robert , Nutman Thomas B , Semnani Roshanak Tolouei 
Published: January 2023

Abstract
A number of features of the host-parasite interface are reminiscent of those that are also observed at the host-cancer interface. Both cancer cells and parasites establish a tissue microenvironment that leads to immune evasion and may be related to alterations in function of various innate cells. Here, we investigate how the phenotype and function of human monocytes is altered by exposure to tumors and if these functional and phenotypic alterations parallel those induced by exposure to helminth parasites. Thus, human monocytes were exposed to three different cancer cell lines (breast, ovarian, or glioblastoma) or to live microfilariae (mf) of Brugia malayi – a causative agent of lymphatic filariasis. After 2 days of culture, cells were harvested, sorted and assessed for mRNA expression, phenotype and function. Monocytes exposed to tumor cell lines showed markedly upregulated expression of M1-associated (TNF-a, IL-1b, IL-8), M2-associated (CCL13, CD206) and Mreg-associated (IL-10, IDO, TGF-b) genes. Similar to cancer cells, but less dramatically mf altered the mRNA expression of IL-1b, CCL13 and IL-8. Similar to the exposure to cancer cell lines, exposure of monocytes to live mf significantly (p&lt;0.05) induced the cell surface expression of the inhibitory ligands PDL1 and PDL2. Finally, exposure of monocytes to cancer cell lines increased the phagocytic ability of these cells, but reduced their ability to induce T cell proliferation, an effect shown to be reversible by PDL1/PD1 blockade. Our data suggest that despite the fact that helminth parasites and tumor cell lines are extraordinarily disparate, they share the ability to alter the phenotype and function of human monocytes and may also share a common mechanism of immune evasion.
The phagosome: Meeting point of the Myddosome, NLRs, and degraded Borrelia burgdorferi
Authors: Cervantes Jorge L. , Benjamin Sarah J. , Chang Yuxiao , Luo Junhong , La Vake Carson J. , Hawley Kelly L. , Caimano Melissa , Vera-Licona Paola , Laubenbacher Reinhard , Ruan Yijun , Radolf Justin , Salazar Juan C. 
Published: January 2023

Abstract
Phagocytosis of the extracellular bacterium Borrelia burgdorferi (Bb) enhances toll-like receptor, NF-κB mediated cytokine responses in human and murine phagocytic cells. TLR adaptor molecule MyD88 is recruited to Bb containing phagosomes, and the spirochetal cargo does not appear to leak from the phagosome into the cytosol. Transcriptome and Network reconstruction analysis identified several master regulators of diverse cellular and molecular processes, including regulation of the TLR-MyD88 pathway, IRFs, cytoskeletal rearrangement, and resolution of inflammation. Surprisingly, genes that code for inflammasome proteins (NLRP3, NOD2 and caspase-1) were also differentially-expressed. We thereby examined the cellular localization of these molecules in Bb-infected WT BMDMs and observed that NLRP3 and NOD2 were observed to colocalize to phagosomes containing degraded spirochetes. NLRP3 also colocalized with MyD88, but only in phagosomes containing degraded spirochetal cargo. Although caspase-1 also colocalized to the phagosome, infection with Bb did not result in an increase in speck formation or secretion of IL-1β.
Our results show that the phagosome is a crucial cellular location not only for degradation of the spirochete, but where components of the Myddosome and inflammasome are recruited. Our findings are in line with recent studies showing that cytosolic receptors can localize to endosomal membranes, and can potentially have an alternate role in regulating an adequate functionality of the phagosome. Our study evidences the complexity of phagosomal signaling in which MyD88 plays a critical role not only in the generation of inflammatory but inducing regulatory signals in murine macrophages upon Bb infection.
Autophagy promotes Rickettsia australis replication in primary murine macrophages
Authors: Bechelli Jeremy Ray , Smalley Claire , Zhao Xuemei , Hwang Seungmin , Walker David Hughes , Fang Rong 
Published: January 2023

Abstract
Rickettsiae are obligately intracellular bacteria that replicate in the cytoplasm of eukaryotic cells. We found autophagy induction and co-localization of bacteria with LC3 (+) autophagosomes in murine bone marrow-derived macrophages (BMMs) upon infection with R. australis. Autophagy induction by rickettsiae in BMMs of Atg5flox/flox mice was completely abrogated in the counterparts of Atg5flox/flox Lyz-Cre animals. Rickettsial replication was significantly greater in BMMs of Atg5flox/flox mice compared to Atg5flox/flox Lyz-Cre mice, suggesting that Atg5-dependent autophagy promotes rickettsial growth in primary mouse macrophages. Inhibition of mTOR signaling also significantly promoted rickettsial replication in macrophages compared to untreated controls. Furthermore, R. australis-infected Atg5flox/flox macrophages secreted significantly lower levels of pro-inflammatory cytokines including inflammasome-dependent IL-1β compared to Atg5flox/flox Lyz-Cre macrophages. Strikingly, rickettsial growth in Atg5flox/flox macrophages was not significantly different from that in Atg5flox/flox Lyz-Cre macrophages when cells were treated with neutralizing antibodies against IL-1β, suggesting that IL-1β is involved in differential bacterial growth in these cells. In line with the in vitro results, the in vivo rickettsial loads in liver, lung and spleen of infected Atg5flox/flox mice were significantly higher than those in Atg5flox/flox Lyz-Cre mice accompanied by a significantly lower level of IL-β in the serum. Taken together, our data demonstrated the role of autophagy in promoting rickettsial replication in mouse macrophages both in vitro and in vivo.
A role of lamina propria ILC1 in the impaired host antibacterial resistance of chronic alcohol consuming mice
Authors: Ito Ichiaki , Asai Akira , McCalla Claudia T , Kobayashi Makiko , Suzuki Fujio 
Published: January 2023

Abstract
Bacterial translocation and subsequent sepsis influenced by ILC1 in lamina propria were studied in chronic alcohol consuming mice (CAC mice) exposed to Enterococcus faecalis oral infection. CAC mice were prepared by an oral gavage of 0.6 ml/day of 20% EtOH for 12 weeks. Control mice received water in the same fashion. All mice were decontaminated and orally infected with 106 CFU/mouse of E. faecalis. The numbers of bacteria in mesenteric lymph nodes (MLNs) and liver of these mice were measured by the colony counting method. Intestines were removed from control and CAC mice, and digested with 100 U/ml of collagenase. Mononuclear cells were isolated from the cell suspension by Percoll density gradient centrifugation. Lineage negative (Lin−) and positive (Lin+) cells were purified magnetically from the mononuclear cells, and analyzed for the population of M1 macrophages (Mϕ) and innate lymphoid cells (ILCs) by flow cytometry. In the results, enterococcal translocation and subsequent sepsis were severely shown in CAC mice, as compared with those of control mice. The number of IFNγ-producing ILC1 was not increased in lamina propria of CAC mice orally infected with E. faecalis, while the large number of ILC1 was isolated from lamina propria of control mice infected with the pathogen. Also, an adequate number of M1Mϕ was isolated from lamina propria of control mice orally infected with E. faecalis, whereas M1Mϕ were not isolated significantly from lamina propria of CAC mice infected with the pathogen. Quiescent Mϕ switch to M1Mϕ in response to IFNγ stimulation. These results suggest that lamina propria ILC1 play an important role in the increased susceptibility of CAC mice to E. faecalis translocation and subsequent sepsis.
The major contribution of IL-1 alpha and caspase-11 in oviduct pathology during Chlamydia infection in the mouse model
Authors: Nagarajan Uma , Allen John , Zhang Yugen , Tripathy Manoj , Montgomery Stephanie 
Published: January 2023

Abstract
The mouse model of genital Chlamydia trachomatis infection simulates the human chlamydial disease resulting in oviduct damage leading to hydrosalpinx. Using this model, we have shown that signaling by IL-1R is a major contributor of oviduct disease during infection. In the current study, we have investigated the specific contribution of IL-1 alpha and IL-1 beta that signal thorough IL-1R. Further, the contribution of caspase11-mediated cell-death that results in the release of IL-1 alpha and IL-1 beta were investigated. IL-1 alpha KO mice developed significantly less incidence (5%) of hydrosalpinx compared to WT mice (75%) (p=&lt;0.001) upon infection. IL-1 beta KO mice had a reduced incidence in hydrosalpinx than WT mice, but significantly higher than IL-1 alpha KO mice. To determine the mechanism of IL-1 alpha release, infection course and pathology in caspase-1-11 KO mice and caspase-11 KO mice were determined. Both caspase-11 and caspase-1-11 KO mice displayed a reduced incidence of hydrosalpinx. Since the caspase-1 adaptor, ASC KO mice do not show a reduced incidence in pathology, our data suggest that caspase-11 activation is sufficient to drive the pathology. Oviduct pathology is a result of excessive PMN infiltration. Flow cytometric analyses demonstrate significantly reduced PMN infiltration to the genital tracts in IL-1 alpha and caspase-11 KO mice. However, T cell infiltration to the genital tracts is unchanged in both the groups, which reflected in normal infection clearance in IL-1 alpha and caspase-11 KO mice. These data suggest that activation of cell death pathways and local release of IL-1 alpha causes long-term damage to the oviducts during Chlamydia infection.
[Supported by PHS funding NIAID AI067678 (UN)]
Antagonising roles between PACT and influenza A virus polymerase subunits in viral replication and innate immune response
Authors: Chan Chi Ping , Yuen Chun-Kit , Fung Sin-Yee , Kew Chun , Yuen Kwok-Yung , Kok Kin-Hang , Jin Dong-Yan 
Published: January 2023

Abstract
Interplay between host innate immune responses and viral antagonism determines the effectiveness of viral replication and pathogenicity. Influenza A virus (IAV) confronts host antiviral responses including type I interferon production using multiple viral proteins such as NS1. We have previously shown that double stranded RNA-binding protein PACT is an essential coactivator of RIG-I in innate antiviral response. In this study, we have further shown that PACT has dual antiviral activity in both interferon-dependent and interferon-independent manners. We found that antiviral activity of PACT is mediated through not only the activation of RIG-I and interferon production but also the direct suppression of IAV polymerase activity. We found that PACT associates with IAV polymerase subunits, namely PB2, PB1 and PA, and inhibits viral replication. On the other hand, the three polymerase subunits also counteract PACT/RIG-I-mediated production of type-I interferon. Taken together, our findings reveal a new mechanism of virus-host interaction demonstrating the mutual antagonism between PACT and IAV polymerases during IAV infection and replication.
Supported by RGC (HKU1/CRF/11G, N-HKU712/12, T11-707/15-R and C7011-15R), HMRF (12111312, 14130862, HKM-15-M01 and 15140662) and S. K. Yee MRF (2011).
Evolution of host-defense function of C-reactive protein from horseshoe crab to humans
Authors: Pathak Asmita , Singh Sanjay K , Thirumalai Avinash , Armstrong Peter B , Agrawal Alok 
Published: January 2023

Abstract
C-reactive protein (CRP) has been conserved throughout evolution. Human native CRP exhibits calcium-dependent binding specificity for phosphocholine. Human CRP in its non-native structure expresses the capability to bind to deposited and conformationally-altered proteins and which can be achieved by several means including treatment of CRP with acidic pH. The ligand-binding property of human CRP in its non-native structure has implications for toxic and inflammatory conditions and favors the conservation of CRP throughout evolution. It is not known, however, whether CRP from invertebrates exhibits structure-based ligand-binding properties similar to that of human CRP. The aim of this study was to investigate the ligand-binding properties of CRP from the American horseshoe crab Limulus polyphemus. We used oxidized low-density lipoprotein (ox-LDL) immobilized on microtiter plates as a model for deposited and conformationally-altered proteins. We found that Limulus CRP binds to ox-LDL at physiological pH, in contrast to human CRP which requires acidic pH to do so. The binding of Limulus CRP to ox-LDL occurred even in the absence of calcium, suggesting that the binding was not mediated through exposed phosphocholine molecules, if any, on ox-LDL. We conclude that the host-defense function of CRP evolved with the development of the immune system to expose a ligand-binding specificity only when needed, that is, an inflammatory microenvironment would have to be sensed by CRP and that CRP would change its structure to execute its function. Limulus CRP also provides us with a tool to investigate the structure-function relationships of human CRP in animal models of inflammation.
Crystal structure of human tetraspanin CD81 reveals a conserved cholesterol binding cavity
Authors: Zimmerman Brandon , McMillan Brian J. , Seegar Tom C.M. , Kruse Andrew C. , Blacklow Stephen C 
Published: January 2023

Abstract
Tetraspanins comprise a diverse family of four-pass transmembrane proteins that play critical roles in cell activation, adhesion, migration and proliferation. CD81/Tspan28, the most widely studied member of the family, forms a complex with CD19, CD21 and CD225 to regulate B cell receptor function, and also acts as a receptor or co-receptor for pathogens such as Hepatitis C virus and Plasmodium species. Despite the fundamental importance of tetraspanin proteins in a broad range of physiologic and pathophysiologic processes, structural information about a full-length tetraspanin has remained elusive. Here we present the first crystal structure of a full-length tetraspanin, human CD81. The transmembrane segments of CD81 pack as two largely separated pairs of helices, not as the four-helix bundle predicted previously. The structure is capped by the large extracellular loop 2 (EC2) at the outer membrane leaflet, and the two pairs of helices converge at the inner leaflet to form a shape resembling an inverted teepee. The transmembrane region contains a large pocket suggestive of a ligand-binding site, offering a potential mechanism for binding lipids or other molecules. In support of this idea, we observe electron density consistent with a bound cholesterol molecule in the pocket, and we detect specific binding of cholesterol to this site in vitro. The discovery of the hydrophobic pocket in the core of the transmembrane domain presents a novel therapeutic avenue for targeting CD81 and other tetraspanins in pathogenic infections or malignancies.
B-Cell Selection in Germinal Centers Elicited by Complex Antigens
Authors: Kuraoka Masayuki , Schmidt Aaron G. , Nojima Takuya , Feng Feng , Watanabe Akiko , Kitamura Daisuke , Harrison Stephen C. , Kepler Thomas B. , Kelsoe Garnett 
Published: January 2023

Abstract
Germinal center (GC) B cells evolve towards increased affinity by a Darwinian process studied intensively in genetically restricted, hapten-specific responses. While experimentally tractable, genetically restricted humoral responses are atypical as antibodies to complex protein antigens represent genetically diverse, polyclonal humoral responses driven by various epitopes arrayed across the antigen. We have developed a single B-cell culture method that supports the proliferation and plasmacytic differentiation of mature and GC B cells. With this tool, we explore the population dynamics of genetically diverse GC responses to two complex antigens – protective antigen of Bacillus anthracis and influenza hemagglutinin – in which B cells compete both intra- and interclonally for distinct epitopes. Our characterizations begin with antigen-binding, mature naïve B cells and follow clonal selection and affinity maturation in GCs. Preferred VH rearrangements among antigen-binding, naïve B cells were similarly abundant in early GCs but, unlike restricted responses to haptens, clonal diversity increased in GC B cells as early “winners” were replaced by rarer, high affinity clones. Despite affinity maturation, half of GC B cells did not detectably bind immunogen but exhibited genetic selection comparable to antigen-binding cells, as determined by VH usage, mutations, and clonal expansion. In GCs elicited by rPA or rHA, interclonal BCR avidities can differ 100-fold and intraclonal avidity by as much as 40-fold. We propose that intraclonal selection in GCs is permissive for a wide range of BCR affinities and that lower affinity/less fit GC B cells may remain viable in GCs for substantially longer periods than generally thought.