JNK pathway restricts DENV2, ZIKV and CHIKV infection by activating complement and apoptosis in mosquito salivary glands

AbstractArbovirus infection of Aedes aegypti salivary glands (SGs) determines transmission. However, there is a dearth of knowledge on SG immunity. Here, we characterized SG immune response to dengue, Zika and chikungunya viruses using high-throughput transcriptomics. The three viruses regulate components of Toll, IMD and JNK pathways. However, silencing of Toll and IMD components showed variable effects on SG infection by each virus. In contrast, regulation of JNK pathway produced consistent responses. Virus infection increased with depletion of component Kayak and decreased with depletion of negative regulator Puckered. Virus-induced JNK pathway regulates complement and apoptosis in SGs via TEP20 and Dronc, respectively. Individual and co-silencing of these genes demonstrate their antiviral effects and that both may function together. Co-silencing either TEP20 or Dronc with Puckered annihilates JNK pathway antiviral effect. We identified and characterized the broad antiviral function of JNK pathway in SGs, expanding the immune arsenal that blocks arbovirus transmission.

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Tissue-autonomous immune response regulates stress signalling during hypertrophy

eLife ◽

10.7554/elife.64919 ◽

2020 ◽

Vol 9 ◽

Author(s):

Robert Krautz ◽

Dilan Khalili ◽

Ulrich Theopold

Keyword(s):

Immune Response ◽

Immune Responses ◽

Salivary Glands ◽

Feedback Loop ◽

Mapk Pathway ◽

Therapeutic Approaches ◽

Jnk Pathway ◽

Immune Effector ◽

Tissue Integrity ◽

Stress Signalling

Postmitotic tissues are incapable of replacing damaged cells through proliferation, but need to rely on buffering mechanisms to prevent tissue disintegration. By constitutively activating the Ras/MAPK-pathway via RasV12-overexpression in the postmitotic salivary glands of Drosophila larvae, we overrode the glands adaptability to growth signals and induced hypertrophy. The accompanied loss of tissue integrity, recognition by cellular immunity and cell death are all buffered by blocking stress signalling through a genuine tissue-autonomous immune response. This novel, spatio-temporally tightly regulated mechanism relies on the inhibition of a feedback-loop in the JNK-pathway by the immune effector and antimicrobial peptide Drosomycin. While this interaction might allow growing salivary glands to cope with temporary stress, continuous Drosomycin expression in RasV12-glands favors unrestricted hypertrophy. These findings indicate the necessity to refine therapeutic approaches that stimulate immune responses by acknowledging their possible, detrimental effects in damaged or stressed tissues.

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JNK pathway-a key mediator of antiviral immunity in mosquito salivary glands

Access Microbiology ◽

10.1099/acmi.imav2019.po0048 ◽

2019 ◽

Vol 1 (10) ◽

Author(s):

Avisha Chowdhury ◽

Cassandra M. Modahl ◽

SiokThing Tan ◽

Benjamin Wong ◽

R. Manjunatha Kini ◽

...

Keyword(s):

Salivary Glands ◽

Antiviral Immunity ◽

Jnk Pathway

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Ultrastructural Analysis of the Salivary Glands of Gromphadorhina Portentosa (Schaum)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100080614 ◽

1977 ◽

Vol 35 ◽

pp. 638-639

Author(s):

P.J. Dailey

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Salivary Glands ◽

Secretory Vesicles ◽

The Past ◽

Transmission Electron ◽

Means Of Transmission ◽

Gromphadorhina Portentosa ◽

Scanning Electron ◽

Topographical Relief

The structure of insect salivary glands has been extensively investigated during the past decade; however, none have attempted scanning electron microscopy (SEM) in ultrastructural examinations of these secretory organs. This study correlates fine structure by means of SEM cryofractography with that of thin-sectioned epoxy embedded material observed by means of transmission electron microscopy (TEM).Salivary glands of Gromphadorhina portentosa were excised and immediately submerged in cold (4°C) paraformaldehyde-glutaraldehyde fixative1 for 2 hr, washed and post-fixed in 1 per cent 0s04 in phosphosphate buffer (4°C for 2 hr). After ethanolic dehydration half of the samples were embedded in Epon 812 for TEM and half cryofractured and subsequently critical point dried for SEM. Dried specimens were mounted on aluminum stubs and coated with approximately 150 Å of gold in a cold sputtering apparatus.Figure 1 shows a cryofractured plane through a salivary acinus revealing topographical relief of secretory vesicles.

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Biogenesis of Catalase-Positive Rods in Excretory Duct Cells of Salivary Glands

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100090294 ◽

1976 ◽

Vol 34 ◽

pp. 62-63

Author(s):

Dwight K. Romanovicz ◽

Jacob S. Hanker

Keyword(s):

Light Microscopy ◽

Salivary Glands ◽

Submandibular Gland ◽

Excretory Duct ◽

Exocrine Glands ◽

Duct Cells ◽

Peroxidatic Activity ◽

Microscopic Studies ◽

Different Dimensions

The presence of catalase-positive rods (Fig. 1) of different dimensions, which frequently have a crystalline appearance by light microscopy, has been reported. They seem to be related to peroxisomes which were characterized morphologically and cytochemically in parotid and other exocrine glands of the rat by Hand in 1973. Our light microscopic studies of these spherical microbodies and rods of different sizes, stained by virtue of the peroxidatic activity of their catalase, indicate that they are almost entirely confined to the cells of the striated and execretory ducts of the submandibular gland in the mouse. The rods were usually noted only in the proximity of the ductal microbodies. The latter frequently showed a tendency to appear in linear close array, or even to be contiguous (Fig. 2). This suggested that the rods could be formed by the fusion of microbodies.

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An adrenocortical oncocytoma with unusual mitochondrial inclusions and cytoplasmic crystals

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100168980 ◽

1994 ◽

Vol 52 ◽

pp. 250-251

Author(s):

W.T. Gunning ◽

G.D. Haselhuhn ◽

E.R. Phillips ◽

S.H. Selman

Keyword(s):

Adrenal Gland ◽

Salivary Glands ◽

Mitotic Activity ◽

Diagnostic Criteria ◽

Vascular Invasion ◽

Benign Neoplasm ◽

Benign Tumors ◽

Nuclear Morphology ◽

Case Presentation ◽

Microscopic Evidence

Within the last few years, adrenal cortical tumors with features concordant with the diagnostic criteria attributed to oncocytomas have been reported. To date, only nine reported cases exist in the literature. This report is the tenth case presentation of a presumptively benign neoplasm of the adrenal gland with a rare differentiation. Oncocytomas are well recognized benign tumors of the thyroid, parathyroid, and salivary glands and of the kidney. Other organs also give rise to these types of tumors, however with less frequency than the former sites. The characteristics generally used to classify a tumor as an oncocytoma include the following criteria: the tumor is 1) usually a solitary circumscribed mass with no gross nor microscopic evidence of metastasis (no tissue nor vascular invasion), 2) fairly bland in terms of mitotic activity and nuclear morphology, and 3) composed of large eosinophillic cells in which the cytoplasm is packed full of mitochondria (Figure 1).

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