microRNAs Facilitate Comprehensive Responses of Bathymodiolinae Mussel Against Symbiotic and Nonsymbiotic Bacteria Stimulation

Abstract Background:As the dominant species inhabiting both cold seeps and hydrothermal vents,Bathymodiolinae mussels are one of the most successful megafauna in the deep sea.They thrive in dark and food-insufficient environmentsby harboring sulfur-oxidizing bacteria (SOB)and/or methane-oxidizing bacteria (MOB)ingill bacteriocytesand obtain the majority of their nutrition from them.Many attempts have been made to decode the mechanisms underlying their symbiosis, which yetremained largely undisclosedfor years due to the lack of cultivable symbionts. In the present study,the globalexpression pattern of immune-related genes and miRNAswere surveyed inGigantidasplatifronsduring bacterial challengesusing enriched symbiontsor nonsymbioticVibrio in attempting to reveal the molecular mechanisms underlying chemosynthetic symbiosis. Results: Multiple PRRs such as TLRs, LRRs and C1q were found vigorously modulated during challenges whiledistinctly clusteredbetween symbiotic and nonsymbiotic bacteria stimulation. As downstream of the immune response,dozens of immune effectors including HSP70, P450, CD82 andvacuolar protein sorting-associated proteinwere modulated simultaneously, contributing to the fine tuning of cellular homeostasis, lysosome activity and bacteria engulfment in either symbiotic and nonsymbiotic bacteria challenge.A total of 459 miRNAs were identified in gill tissue of G. platifrons while dozens of themwere differentially expressedduring the challenge.Among these miRNAs, some were also found in differentexpression patternbetween symbiont or nonsymbiontchallenges and targeting apoptosis and phagosome maturation-related genes, including caspase8, inhibitor of apoptosis, cAMP-responsive element-binding protein,IκB, Rab and integrin. Conclusion:It was suggested that G. platifrons PRRs might function cooperativelyto facilitate the specialized immune recognition to MOBs or nonsymbioticbacteria. Meanwhile, a shared expression pattern of immune effectorswas observed between bacterial challenges, indicatingthe conservative response of Bathymodiolinae mussels in promoting the adhesion andengulfment of symbionts and nonsymbiont. Nevertheless, the differentially expressed miRNAs were yet suggested to facilitate specialized modulationinsymbiosis by repressing apoptosis- and phagosome maturation-related genes.With the orchestra of immune-related genes and miRNAs, G. platifronsmussels could therefore maintain arobust immune response against invading pathogens while establishing symbiosis with chemosynthetic bacteria.

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Genomic Insights Into Chemosynthetic Symbiosis in a Deep-Sea Hydrothermal Vent Mussel

10.21203/rs.3.rs-1220069/v1 ◽

2022 ◽

Author(s):

Kai Zhang ◽

Yao Xiao ◽

Jin Sun ◽

Ting Xu ◽

Kun Zhou ◽

...

Keyword(s):

Deep Sea ◽

Hydrothermal Vent ◽

Hydrothermal Vents ◽

Molecular Mechanisms ◽

Gene Families ◽

Functional Differentiation ◽

Cold Seeps ◽

Proteomic Approach ◽

Immune Related Genes ◽

Self Protection

Abstract Background Symbiosis with chemosynthetic bacteria has allowed many invertebrates to flourish in ‘extreme’ deep-sea chemosynthesis-based ecosystems, such as hydrothermal vents and cold seeps. Bathymodioline mussels are considered as models of deep-sea animal-bacteria symbiosis, but the diversity of molecular mechanisms governing host-symbiont interactions remains understudied owing to the lack of hologenomes. In this study, we adopted a total hologenome approach in sequencing the hydrothermal vent mussel Bathymodiolus marisindicus and the endosymbiont genomes combined with a transcriptomic and proteomic approach that explore the mechanisms of symbiosis. Results Here, we provide the first coupled mussel-endosymbiont genome assembly. Comparative genome analysis revealed that both Bathymodiolus marisindicus and its endosymbiont reshape their genomes through the expansion of gene families, likely due to chemosymbiotic adaptation. Functional differentiation of host immune-related genes and attributes of symbiont self-protection that likely facilitate the establishment of endosymbiosis. Hologenomic analyses offer new evidence that metabolic complementarity between the host and endosymbionts enables the host to compensate for its inability to synthesize some essential nutrients, and two pathways (digestion of symbionts and molecular leakage of symbionts) that can supply the host with symbiontderived nutrients. Results also showed that bacteriocin and abundant toxins of symbiont may contribute to the defense of the B. marisindicus holobiont. Moreover, an exceptionally large number of anti-virus systems were identified in the B. marisindicus symbiont, which likely work synergistically to efficiently protect their hosts from phage infection, indicating virus-bacteria interactions in intracellular environments of a deepsea vent mussel. Conclusions Our study provides novel insights into the mechanisms of symbiosis enabling deep-sea mussels to successfully colonize the special hydrothermal vent habitats.

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A Toll-like receptor identified in Gigantidas platifrons and its potential role in the immune recognition of endosymbiotic methane oxidation bacteria

PeerJ ◽

10.7717/peerj.11282 ◽

2021 ◽

Vol 9 ◽

pp. e11282

Author(s):

Mengna Li ◽

Hao Chen ◽

Minxiao Wang ◽

Zhaoshan Zhong ◽

Hao Wang ◽

...

Keyword(s):

Hydrothermal Vents ◽

Lipid A ◽

Cold Seeps ◽

Immune Recognition ◽

Recognition Mechanism ◽

Surface Plasmon Resonance Analysis ◽

Resonance Analysis ◽

Methane Oxidizing Bacteria ◽

Chemosynthetic Bacteria ◽

Lipid A Structure

Symbiosis with chemosynthetic bacteria is an important ecological strategy for the deep-sea megafaunas including mollusks, tubeworms and crustacean to obtain nutrients in hydrothermal vents and cold seeps. How the megafaunas recognize symbionts and establish the symbiosis has attracted much attention. Bathymodiolinae mussels are endemic species in both hydrothermal vents and cold seeps while the immune recognition mechanism underlying the symbiosis is not well understood due to the nonculturable symbionts. In previous study, a lipopolysaccharide (LPS) pull-down assay was conducted in Gigantidas platifrons to screen the pattern recognition receptors potentially involved in the recognition of symbiotic methane-oxidizing bacteria (MOB). Consequently, a total of 208 proteins including GpTLR13 were identified. Here the molecular structure, expression pattern and immune function of GpTLR13 were further analyzed. It was found that GpTLR13 could bind intensively with the lipid A structure of LPS through surface plasmon resonance analysis. The expression alternations of GpTLR13 transcripts during a 28-day of symbiont-depletion assay were investigated by real-time qPCR. As a result, a robust decrease of GpTLR13 transcripts was observed accompanying with the loss of symbionts, implying its participation in symbiosis. In addition, GpTLR13 transcripts were found expressed exclusively in the bacteriocytes of gills of G. platifrons by in situ hybridization. It was therefore speculated that GpTLR13 may be involved in the immune recognition of symbiotic methane-oxidizing bacteria by specifically recognizing the lipid A structure of LPS. However, the interaction between GpTLR13 and symbiotic MOB was failed to be addressed due to the nonculturable symbionts. Nevertheless, the present result has provided with a promising candidate as well as a new approach for the identification of symbiont-related genes in Bathymodiolinae mussels.

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Hematological disorder associated Cxcr4-gain-of-function mutation leads to uncontrolled extrafollicular immune response

Blood ◽

10.1182/blood.2020007450 ◽

2021 ◽

Author(s):

Nagham Alouche ◽

Amélie Bonaud ◽

Vincent Rondeau ◽

Rim Hussein-Agha ◽

Julie Nguyen ◽

...

Keyword(s):

Immune Response ◽

B Cells ◽

Molecular Mechanisms ◽

Plasma Cells ◽

Fine Tuning ◽

Transient Wave ◽

Gain Of Function ◽

Hematological Disorders ◽

Cxcr4 Signaling ◽

Whim Syndrome

The extrafollicular immune response is essential to generate a rapid but transient wave of protective antibodies upon infection. Despite its importance, the molecular mechanisms controlling this first response are poorly understood. Here, we demonstrate that enhanced Cxcr4 signaling due to defective receptor desensitization leads to exacerbated extrafollicular B cell response. Using a mouse model bearing a gain of function mutation of Cxcr4 described in two human hematological disorders, WHIM syndrome and Waldenström's Macroglobulinemia, we demonstrated that mutant B cells exhibited enhanced mTOR signaling, cycled more and differentiated more potently into plasma cells than wild-type B cells upon TLR stimulation. Moreover, Cxcr4 gain-of-function promoted enhanced homing and persistence of immature plasma cells in the bone marrow, a phenomenon recapitulated in WHIM syndrome patient samples. This translated in increased and more sustained production of antibodies upon T-independent immunization in Cxcr4 mutant mice. Thus, our results establish that fine-tuning of Cxcr4 signaling is essential to limit the strength and length of the extrafollicular immune response.

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Modulation of the Immune Response by Deferasirox in Myelodysplastic Syndrome Patients

Pharmaceuticals ◽

10.3390/ph14010041 ◽

2021 ◽

Vol 14 (1) ◽

pp. 41

Author(s):

Hana Votavova ◽

Zuzana Urbanova ◽

David Kundrat ◽

Michaela Dostalova Merkerova ◽

Martin Vostry ◽

...

Keyword(s):

Gene Expression ◽

Immune Response ◽

Blood Cell ◽

Myelodysplastic Syndrome ◽

Molecular Mechanisms ◽

Expression Profiles ◽

Adaptive Immune Response ◽

Gene Expression Profiles ◽

Iron Chelator ◽

Multiple Cancer

Deferasirox (DFX) is an oral iron chelator used to reduce iron overload (IO) caused by frequent blood cell transfusions in anemic myelodysplastic syndrome (MDS) patients. To study the molecular mechanisms by which DFX improves outcome in MDS, we analyzed the global gene expression in untreated MDS patients and those who were given DFX treatment. The gene expression profiles of bone marrow CD34+ cells were assessed by whole-genome microarrays. Initially, differentially expressed genes (DEGs) were determined between patients with normal ferritin levels and those with IO to address the effect of excessive iron on cellular pathways. These DEGs were annotated to Gene Ontology terms associated with cell cycle, apoptosis, adaptive immune response and protein folding and were enriched in cancer-related pathways. The deregulation of multiple cancer pathways in iron-overloaded patients suggests that IO is a cofactor favoring the progression of MDS. The DEGs between patients with IO and those treated with DFX were involved predominantly in biological processes related to the immune response and inflammation. These data indicate DFX modulates the immune response mainly via neutrophil-related genes. Suppression of negative regulators of blood cell differentiation essential for cell maturation and upregulation of heme metabolism observed in DFX-treated patients may contribute to the hematopoietic improvement.

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Deficiency of Lipin2 Results in Enhanced NF-κB Signaling and Osteoclast Formation in RAW-D Murine Macrophages

International Journal of Molecular Sciences ◽

10.3390/ijms22062893 ◽

2021 ◽

Vol 22 (6) ◽

pp. 2893

Author(s):

Asami Watahiki ◽

Seira Hoshikawa ◽

Mitsuki Chiba ◽

Hiroshi Egusa ◽

Satoshi Fukumoto ◽

...

Keyword(s):

Molecular Mechanisms ◽

Inflammatory Responses ◽

Osteoclast Formation ◽

Fine Tuning ◽

Nuclear Accumulation ◽

Innate Immune Responses ◽

Osteoclastic Resorption ◽

Bone Disorder ◽

Proinflammatory Responses ◽

Potential Therapeutic Intervention

Lipin2 is a phosphatidate phosphatase that plays critical roles in fat homeostasis. Alterations in Lpin2, which encodes lipin2, cause the autoinflammatory bone disorder Majeed syndrome. Lipin2 limits lipopolysaccharide (LPS)-induced inflammatory responses in macrophages. However, little is known about the precise molecular mechanisms underlying its anti-inflammatory function. In this study, we attempted to elucidate the molecular link between the loss of lipin2 function and autoinflammatory bone disorder. Using a Lpin2 knockout murine macrophage cell line, we showed that lipin2 deficiency enhances innate immune responses to LPS stimulation through excessive activation of the NF-κB signaling pathway, partly because of TAK1 signaling upregulation. Lipin2 depletion also enhanced RANKL-mediated osteoclastogenesis and osteoclastic resorption activity accompanied by NFATc1 dephosphorylation and increased nuclear accumulation. These results suggest that lipin2 suppresses the development of autoinflammatory bone disorder by fine-tuning proinflammatory responses and osteoclastogenesis in macrophages. Therefore, this study provides insights into the molecular pathogenesis of monogenic autoinflammatory bone disorders and presents a potential therapeutic intervention.

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Why Does SARS-CoV-2 Infection Induce Autoantibody Production?

Pathogens ◽

10.3390/pathogens10030380 ◽

2021 ◽

Vol 10 (3) ◽

pp. 380

Author(s):

Ales Macela ◽

Klara Kubelkova

Keyword(s):

Immune Response ◽

Immune System ◽

Host Cell ◽

Critical Role ◽

Cell Interaction ◽

Immune Recognition ◽

Autoantibody Production ◽

Host Cell Interaction ◽

Primary Virus

SARS-CoV-2 infection induces the production of autoantibodies, which is significantly associated with complications during hospitalization and a more severe prognosis in COVID-19 patients. Such a response of the patient’s immune system may reflect (1) the dysregulation of the immune response or (2) it may be an attempt to regulate itself in situations where the non-infectious self poses a greater threat than the infectious non-self. Of significance may be the primary virus-host cell interaction where the surface-bound ACE2 ectoenzyme plays a critical role. Here, we present a brief analysis of recent findings concerning the immune recognition of SARS-CoV-2, which, we believe, favors the second possibility as the underlying reason for the production of autoantibodies during COVID-19.

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TAMI-07. THE IMMUNE MICROENVIRONMENT IN LOWER GRADE GLIOMAS

Neuro-Oncology ◽

10.1093/neuonc/noaa215.896 ◽

2020 ◽

Vol 22 (Supplement_2) ◽

pp. ii214-ii214

Author(s):

Anupam Kumar ◽

Katharine Chen ◽

Claudia Petritsch ◽

Theodore Nicolaides ◽

Mariarita Santi-Vicini ◽

...

Keyword(s):

Immune Response ◽

T Cells ◽

Cd8 T Cells ◽

Molecular Mechanisms ◽

T Regulatory Cells ◽

Immune Cell ◽

T Cell Response ◽

Cytotoxic T Cell ◽

Lower Grade ◽

Functional Relationships

Abstract The determinants of the tumor-associated immune response in brain tumors are poorly understood. Using tumor samples from two molecularly distinct subtypes of lower grade glioma, MAPK-driven glioma with biallelic inactivation of CDKN2A (n=30) and IDH-mutant, 1p/19q-intact astrocytoma (n=29), we demonstrate qualitative and quantitative differences in the tumor-associated immune response and we investigate the molecular mechanisms involved. Histologically the MAPK-driven gliomas were comprised of pleomorphic xanthoastrocytoma (PXA) (n=11) and anaplastic PXA (n=19). Seven patients had paired samples from two sequential surgeries. Immune cell populations and their activity were determined by quantitative multiplex immunostaining and Digital Spatial Profiling and gene expression was analyzed by Nanostring. Functional studies were performed using established cell lines and two new patient-derived lines from MAPK-driven LGGs. MAPK-driven tumors exhibited an increased number of CD8+ T cells and tumor-associated microglial/macrophage (TAMs), including CD163+ TAMs, as compared to IDH-mutant astrocytoma. In contrast, IDH-mutant tumors had increased FOXP3+ immunosuppressive T regulatory cells. Transcriptional and protein level analyses in MAPK-driven tumors suggested an active cytotoxic T cell response with robust expression of granzyme B, present on 27% of CD8+ T cells, increased MHC class I expression, and altered cytokine profiles. Interestingly, MAPK-driven tumors also had increased expression of immunosuppressive molecules, including CXCR4, PD-L1, and VEGFA. Expression differences for cell surface and secreted proteins were confirmed in patient-derived tumor lines and functional relationships between altered chemokine expression and immune cell infiltration was investigated. Our data provide novel insights into the immune contexture of MAPK driven LGGs and suggest MAPK driven gliomas with biallelic inactivation of CDKN2A may be particularly vulnerable to immunotherapeutic modulation

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Decoding the temporal nature of brain GR activity in the NFκB signal transition leading to depressive-like behavior

Molecular Psychiatry ◽

10.1038/s41380-021-01016-1 ◽

2021 ◽

Author(s):

Young-Min Han ◽

Min Sun Kim ◽

Juyeong Jo ◽

Daiha Shin ◽

Seung-Hae Kwon ◽

...

Keyword(s):

Inhibitory Action ◽

Time Course ◽

Molecular Mechanisms ◽

Late Phase ◽

Fine Tuning ◽

Dependent Manner ◽

Middle Phase ◽

Temporal Shift

AbstractThe fine-tuning of neuroinflammation is crucial for brain homeostasis as well as its immune response. The transcription factor, nuclear factor-κ-B (NFκB) is a key inflammatory player that is antagonized via anti-inflammatory actions exerted by the glucocorticoid receptor (GR). However, technical limitations have restricted our understanding of how GR is involved in the dynamics of NFκB in vivo. In this study, we used an improved lentiviral-based reporter to elucidate the time course of NFκB and GR activities during behavioral changes from sickness to depression induced by a systemic lipopolysaccharide challenge. The trajectory of NFκB activity established a behavioral basis for the NFκB signal transition involved in three phases, sickness-early-phase, normal-middle-phase, and depressive-like-late-phase. The temporal shift in brain GR activity was differentially involved in the transition of NFκB signals during the normal and depressive-like phases. The middle-phase GR effectively inhibited NFκB in a glucocorticoid-dependent manner, but the late-phase GR had no inhibitory action. Furthermore, we revealed the cryptic role of basal GR activity in the early NFκB signal transition, as evidenced by the fact that blocking GR activity with RU486 led to early depressive-like episodes through the emergence of the brain NFκB activity. These results highlight the inhibitory action of GR on NFκB by the basal and activated hypothalamic-pituitary-adrenal (HPA)-axis during body-to-brain inflammatory spread, providing clues about molecular mechanisms underlying systemic inflammation caused by such as COVID-19 infection, leading to depression.

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MicroRNAs: Biological Regulators in Pathogen–Host Interactions

Cells ◽

10.3390/cells9010113 ◽

2020 ◽

Vol 9 (1) ◽

pp. 113 ◽

Cited By ~ 3

Author(s):

Stephanie Maia Acuña ◽

Lucile Maria Floeter-Winter ◽

Sandra Marcia Muxel

Keyword(s):

Immune Response ◽

Infectious Diseases ◽

Small Rnas ◽

Immune Cell ◽

Fine Tuning ◽

Biological Processes ◽

Host Interactions ◽

The Past ◽

Biological Aspects

An inflammatory response is essential for combating invading pathogens. Several effector components, as well as immune cell populations, are involved in mounting an immune response, thereby destroying pathogenic organisms such as bacteria, fungi, viruses, and parasites. In the past decade, microRNAs (miRNAs), a group of noncoding small RNAs, have emerged as functionally significant regulatory molecules with the significant capability of fine-tuning biological processes. The important role of miRNAs in inflammation and immune responses is highlighted by studies in which the regulation of miRNAs in the host was shown to be related to infectious diseases and associated with the eradication or susceptibility of the infection. Here, we review the biological aspects of microRNAs, focusing on their roles as regulators of gene expression during pathogen–host interactions and their implications in the immune response against Leishmania, Trypanosoma, Toxoplasma, and Plasmodium infectious diseases.

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From wood to vent: first cocculinid limpet associated with hydrothermal activity discovered in the Weddell Sea

Antarctic Science ◽

10.1017/s095410202000022x ◽

2020 ◽

Vol 32 (5) ◽

pp. 354-366

Author(s):

Chong Chen ◽

Katrin Linse

Keyword(s):

Hydrothermal Vents ◽

Deep Ocean ◽

First Record ◽

Hydrothermal Activity ◽

Integrative Taxonomy ◽

Weddell Sea ◽

Anatomical Reconstruction ◽

Cold Seeps ◽

Evolutionary Trajectory ◽

Genetic Sequencing

AbstractLush ‘oases’ of life seen in chemosynthetic ecosystems such as hot vents and cold seeps represent rare, localized exceptions to the generally oligotrophic deep ocean floor. Organic falls, best known from sunken wood and whale carcasses, are additional sources of such oases. Kemp Caldera (59°42'S, 28°20'W) in the Weddell Sea exhibits active hydrothermal vents and a natural whale fall in close proximity, where an undescribed cocculinid limpet was found living in both types of chemosynthetic habitats. This represents the first member of the gastropod order Cocculinida discovered from hot vents, and also the first record from the Southern Ocean. Here, we applied an integrative taxonomy framework incorporating traditional dissection, electron microscopy, genetic sequencing and 3D anatomical reconstruction through synchrotron computed tomography in order to characterize this species. Together, our data revealed an unusual member of the genus Cocculina with a highly modified radula for feeding on bacterial film, described herein as Cocculina enigmadonta n. sp. Its phylogenetically derived position within the largely wood-inhabiting Cocculina indicates that it probably evolved from an ancestor adapted to living on sunken wood, providing a compelling case of the ‘stepping stone’ evolutionary trajectory from organic falls to seeps and vents.

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