scholarly journals Conditional ablation of macrophages disrupts ovarian vasculature

Reproduction ◽  
2011 ◽  
Vol 141 (6) ◽  
pp. 821-831 ◽  
Author(s):  
Emily C Turner ◽  
Jeremy Hughes ◽  
Helen Wilson ◽  
Michael Clay ◽  
Katie J Mylonas ◽  
...  

Macrophages are the most abundant immune cell within the ovary. Their dynamic distribution throughout the ovarian cycle and heterogenic array of functions suggest the involvement in various ovarian processes, but their functional role has yet to be fully established. The aim was to induce conditional macrophage ablation to elucidate the putative role of macrophages in maintaining the integrity of ovarian vasculature. Using the CD11b-diphtheria toxin receptor (DTR) mouse, in which expression of human DTR is under the control of the macrophage-specific promoter sequence CD11b, ovarian macrophages were specifically ablated in adult females by injections of diphtheria toxin (DT). CD11b-DTR mice were given DT treatment or vehicle and ovaries collected at 2, 8, 16, 24 and 48 h. Histochemical stains were employed to characterise morphological changes, immunohistochemistry for F4/80 to identify macrophages and the endothelial cell marker CD31 used to quantify vascular changes. In normal ovaries, macrophages were detected in corpora lutea and in the theca layer of healthy and atretic follicles. As macrophage ablation progressed, increasing amounts of ovarian haemorrhage were observed affecting both luteal and thecal tissue associated with significant endothelial cell depletion, increased erythrocyte accumulation and increased follicular atresia by 16 h. These events were followed by necrosis and profound structural damage. Changes were limited to the ovary, as DT treatment does not disrupt the vasculature of other tissues likely reflecting the unique cyclical nature of the ovarian vasculature and heterogeneity between macrophages within different tissues. These results show that macrophages play a critical role in maintaining ovarian vascular integrity.

2020 ◽  
Author(s):  
Elisabeth G. Vichaya ◽  
Sajida Malik ◽  
Luba Sominsky ◽  
Bianca G. Ford ◽  
Sarah J. Spencer ◽  
...  

Abstract Background: Production of inflammatory mediators by reactive microglial cells in the brain is generally considered the primary mechanism underlying the development of symptoms of sickness in response to systemic inflammation.Methods: Depletion of microglia was achieved in C57BL/6 mice by chronic oral administration of PLX5622, a specific antagonist of colony stimulating factor-1 receptor, and in rats by a knock-in model in which the diphtheria toxin receptor was expressed under the control of the endogenous fractalkine receptor (CX3CR1) promoter sequence. After successful microglia depletion, mice and rats were injected with a sickness-inducing dose of lipopolysaccharide according to a 2 (depletion versus control) x 2 (LPS versus saline) factorial design. Sickness was measured by body weight loss and decreased locomotor activity in rats and mice, and reduced voluntary wheel running in mice. Results: Chronic administration of PLX5622 in mice and administration of diphtheria toxin to knock-in rats depleted microglia and peripheral tissue macrophages. However, it did not abrogate the inducible expression of proinflammatory cytokines in the brain in response to LPS and even exacerbated it for some of the cytokines. In accordance with these neuroimmune effects, LPS-induced sickness was not abrogated, rather it was exacerbated when measured by running wheel activity in mice. Conclusions: These findings reveal that the sickness-inducing effects of acute inflammation can develop independently of microglia activation.


Blood ◽  
2001 ◽  
Vol 98 (9) ◽  
pp. 2869-2871 ◽  
Author(s):  
Shigeru Yanagi ◽  
Ryoko Inatome ◽  
Junyi Ding ◽  
Hironori Kitaguchi ◽  
Victor L. J. Tybulewicz ◽  
...  

Abstract Mice deficient in the Syk tyrosine kinase showed severe petechiae in utero and died shortly after birth. The mechanism of this bleeding, however, remains unknown. Here it is shown that this bleeding is caused by morphologic defects of Syk-deficient endothelial cells during embryogenesis. Immunoblot and reverse transcriptase–polymerase chain reaction Northern blot analysis indicated that Syk is expressed in several endothelial cell lines. Immunocytochemical analysis also confirmed that Syk is expressed in the normal embryonic endothelial cells and is absent in Syk-deficient mice. Furthermore, electron microscopic analysis of Syk-deficient mice revealed an abnormal morphogenesis and a decreased number of endothelial cells. The results indicate a critical role for Syk in endothelial cell function and in maintaining vascular integrity in vivo.


2020 ◽  
Author(s):  
Vivek V Thacker ◽  
Kunal Sharma ◽  
Neeraj Dhar ◽  
Gian-Filippo Mancini ◽  
Jessica Sordet-Dessimoz ◽  
...  

AbstractSevere cases of COVID-19 present with hypercoagulopathies and systemic endothelialitis of the lung microvasculature. The dynamics of vascular damage, and whether it is a direct consequence of endothelial infection or an indirect consequence of immune cell mediated cytokine storms is unknown. This is in part because in vitro models are typically epithelial cell monocultures or fail to recapitulate vascular physiology. We use a vascularised lung-on-chip model where, consistent with monoculture reports, low numbers of SARS-CoV-2 virions are released apically from alveolar epithelial cells. However, rapid infection of the underlying endothelial layer leads to the generation of clusters of endothelial cells with low or no CD31 expression, a progressive loss of endothelial barrier integrity, and a pro-coagulatory microenvironment. These morphological changes do not occur if these cells are exposed to the virus apically. Viral RNA persists in individual cells, which generates a response that is skewed towards NF-KB mediated inflammation, is typified by IL-6 secretion even in the absence of immune cells, and is transient in epithelial cells but persistent in endothelial cells. Perfusion with Tocilizumab, an inhibitor of trans IL-6 signalling slows the loss of barrier integrity but does not prevent the formation of endothelial cell clusters with reduced CD31 expression. SARS-CoV-2 mediated endothelial cell damage occurs despite a lack of rapid viral replication, in a cell-type specific manner and independently of immune-cell mediated cytokine storms, whose effect would only exacerbate the damage.


Blood ◽  
2011 ◽  
Vol 118 (2) ◽  
pp. 464-472 ◽  
Author(s):  
Yoshito Takeda ◽  
Qinglin Li ◽  
Alexander R. Kazarov ◽  
Mathieu Epardaud ◽  
Kutlu Elpek ◽  
...  

Abstract Tetraspanin protein CD151 on tumor cells supports invasion and metastasis. In the present study, we show that host animal CD151 also plays a critical role. CD151-null mice showed markedly diminished experimental lung metastasis after injection of Lewis lung carcinoma or B16F10 melanoma cells. Diminished tumor cell residence in the lungs was evident 6-24 hours after injection. Consistent with an endothelial cell deficiency, isolated CD151-null mouse lung endothelial cells showed diminished support for B16F10 adhesion and transendothelial migration, diminished B16F10-induced permeability, and diminished B16F10 adhesion to extracellular matrix deposited by CD151-null mouse lung endothelial cells. However, CD151 deletion did not affect the size of metastatic foci or subcutaneous primary B16F10 tumors, tumor aggregation, tumor clearance from the blood, or tumor-induced immune cell activation and recruitment. Therefore, the effects of host CD151 on metastasis do not involve altered local tumor growth or immune surveillance. VEGF-induced endothelial cell signaling through Src and Akt was diminished in CD151-null endothelial cells. However, deficient signaling was not accompanied by reduced endothelial permeability either in vitro (monolayer permeability assay) or in vivo (VEGF-stimulated Miles assay). In summary, diminished metastasis in CD151-null host animals may be due to impaired tumor-endothelial interactions, with underlying defects in mouse lung endothelial cell extracellular matrix production.


Endocrinology ◽  
2005 ◽  
Vol 146 (3) ◽  
pp. 1301-1311 ◽  
Author(s):  
Samuel A. Pauli ◽  
Hongyan Tang ◽  
Jeff Wang ◽  
Peter Bohlen ◽  
Robert Posser ◽  
...  

The vascular endothelial growth factor (VEGF)/VEGF receptor 2 (VEGFR-2) pathway regulates proliferation, survival, and permeability of vasculature. This pathway is active during the formation of a corpus luteum, a highly vascularized, endocrine organ with a short life span during the nonpregnant state. In the pregnant state, the life span of corpora lutea is much longer because they play a critical role in supporting pregnancy development. We hypothesized that the VEGF/VEGFR-2 pathway plays a critical role in regulating angiogenic events in the corpora lutea of pregnancy. Injection of the neutralizing anti-VEGFR-2 antibody DC101 (ImClone Systems, Inc., New York, NY) on embryonic d 3.5 (preimplantation) or 6.5 (postimplantation) disrupts function of the corpora lutea of pregnancy in CD1 mice, as evidenced by a decrease in organ size, regression of luteal vessels, and a fall in progesterone secretion within 24 h postinjection. Inhibition of the VEGFR-2 caused removal of endothelial cells, mostly through endothelial cell detachment from the vascular basement membrane. Luteal steroid-producing epithelial cells were eliminated through apoptosis secondary to vasculature becoming dysfunctional. Disruption of luteal function caused arrest of embryonic development. The effect of antibody is specific to the ovary, because pregnancy progresses normally in ovariectomized, progesterone-replaced animals treated with anti-VEGFR-2 antibody. Embryonic blood vessels were not affected directly by the antibody, because it did not reach the embryo. Administration of an antibody against VE-cadherin (E4G10), which specifically blocks endothelial proliferation, did not disrupt luteal function and pregnancy development. Thus, VEGFR-2-mediated endothelial cell signals are critical to maintain functionality of luteal blood vessels during pregnancy. Potential clinical applications of inhibitors of the VEGF/VEGFR-2 pathway include emergency contraception and medical treatment of ectopic and abnormal intrauterine pregnancies.


2020 ◽  
Author(s):  
Elisabeth G. Vichaya ◽  
Sajida Malik ◽  
Luba Sominsky ◽  
Bianca G. Ford ◽  
Sarah J. Spencer ◽  
...  

Abstract Background: Production of inflammatory mediators by reactive microglial cells in the brain is generally considered the primary mechanism underlying the development of symptoms of sickness in response to systemic inflammation.Methods: Depletion of microglia was achieved in C57BL/6 mice by chronic oral administration of PLX5622, a specific antagonist of colony stimulating factor-1 receptor, and in rats by a knock-in model in which the diphtheria toxin receptor was expressed under the control of the endogenous fractalkine receptor (Cx3cr1) promoter sequence. After successful microglia depletion, mice and rats were injected with a sickness-inducing dose of lipopolysaccharide according to a 2 (depletion versus control) x 2 (LPS versus saline) factorial design. Sickness was measured by body weight loss and decreased locomotor activity in rats and mice, and reduced voluntary wheel running in mice. Results: Chronic administration of PLX5622 in mice and administration of diphtheria toxin to knock-in rats depleted microglia and peripheral tissue macrophages. However, it did not abrogate the inducible expression of proinflammatory cytokines in the brain in response to LPS and even exacerbated it for some of the cytokines. In accordance with these neuroimmune effects, LPS-induced sickness was not abrogated, rather it was exacerbated when measured by running wheel activity in mice. Conclusions: These findings reveal that the sickness-inducing effects of acute inflammation can develop independently of microglia activation.


2021 ◽  
Vol 22 (9) ◽  
pp. 4961
Author(s):  
Maria Kovalska ◽  
Eva Baranovicova ◽  
Dagmar Kalenska ◽  
Anna Tomascova ◽  
Marian Adamkov ◽  
...  

L-methionine, an essential amino acid, plays a critical role in cell physiology. High intake and/or dysregulation in methionine (Met) metabolism results in accumulation of its intermediate(s) or breakdown products in plasma, including homocysteine (Hcy). High level of Hcy in plasma, hyperhomocysteinemia (hHcy), is considered to be an independent risk factor for cerebrovascular diseases, stroke and dementias. To evoke a mild hHcy in adult male Wistar rats we used an enriched Met diet at a dose of 2 g/kg of animal weight/day in duration of 4 weeks. The study contributes to the exploration of the impact of Met enriched diet inducing mild hHcy on nervous tissue by detecting the histo-morphological, metabolomic and behavioural alterations. We found an altered plasma metabolomic profile, modified spatial and learning memory acquisition as well as remarkable histo-morphological changes such as a decrease in neurons’ vitality, alterations in the morphology of neurons in the selective vulnerable hippocampal CA 1 area of animals treated with Met enriched diet. Results of these approaches suggest that the mild hHcy alters plasma metabolome and behavioural and histo-morphological patterns in rats, likely due to the potential Met induced changes in “methylation index” of hippocampal brain area, which eventually aggravates the noxious effect of high methionine intake.


Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 254
Author(s):  
Michel-Edwar Mickael ◽  
Norwin Kubick ◽  
Pavel Klimovich ◽  
Patrick Henckell Flournoy ◽  
Irmina Bieńkowska ◽  
...  

Infiltration of the endothelial layer of the blood-brain barrier by leukocytes plays a critical role in health and disease. When passing through the endothelial layer during the diapedesis process lymphocytes can either follow a paracellular route or a transcellular one. There is a debate whether these two processes constitute one mechanism, or they form two evolutionary distinct migration pathways. We used artificial intelligence, phylogenetic analysis, HH search, ancestor sequence reconstruction to investigate further this intriguing question. We found that the two systems share several ancient components, such as RhoA protein that plays a critical role in controlling actin movement in both mechanisms. However, some of the key components differ between these two transmigration processes. CAV1 genes emerged during Trichoplax adhaerens, and it was only reported in transcellular process. Paracellular process is dependent on PECAM1. PECAM1 emerged from FASL5 during Zebrafish divergence. Lastly, both systems employ late divergent genes such as ICAM1 and VECAM1. Taken together, our results suggest that these two systems constitute two different mechanical sensing mechanisms of immune cell infiltrations of the brain, yet these two systems are connected. We postulate that the mechanical properties of the cellular polarity is the main driving force determining the migration pathway. Our analysis indicates that both systems coevolved with immune cells, evolving to a higher level of complexity in association with the evolution of the immune system.


2021 ◽  
Vol 22 (8) ◽  
pp. 3955
Author(s):  
László Bálint ◽  
Zoltán Jakus

Our understanding of the function and development of the lymphatic system is expanding rapidly due to the identification of specific molecular markers and the availability of novel genetic approaches. In connection, it has been demonstrated that mechanical forces contribute to the endothelial cell fate commitment and play a critical role in influencing lymphatic endothelial cell shape and alignment by promoting sprouting, development, maturation of the lymphatic network, and coordinating lymphatic valve morphogenesis and the stabilization of lymphatic valves. However, the mechanosignaling and mechanotransduction pathways involved in these processes are poorly understood. Here, we provide an overview of the impact of mechanical forces on lymphatics and summarize the current understanding of the molecular mechanisms involved in the mechanosensation and mechanotransduction by lymphatic endothelial cells. We also discuss how these mechanosensitive pathways affect endothelial cell fate and regulate lymphatic development and function. A better understanding of these mechanisms may provide a deeper insight into the pathophysiology of various diseases associated with impaired lymphatic function, such as lymphedema and may eventually lead to the discovery of novel therapeutic targets for these conditions.


2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 178-179
Author(s):  
S. Alehashemi ◽  
M. Garg ◽  
B. Sellers ◽  
A. De Jesus ◽  
A. Biancotto ◽  
...  

Background:Systemic Autoinflammatory diseases present with sterile inflammation. NOMID (Neonatal-Onset Multisystem Inflammatory Disease) is caused by gain-of-function mutations inNLRP3and excess IL-1 production, presents with fever, neutrophilic dermatosis, aseptic meningitis, hearing loss and eye inflammation; CANDLE (Chronic Atypical Neutrophilic Dermatosis, Lipodystrophy and Elevated Temperature) is caused by loss-of-function mutations in proteasome genes that lead to type-1 interferon signaling, characterized by fever, panniculitis, lipodystrophy, cytopenia, systemic and pulmonary hypertension and basal ganglia calcification. IL-1 blockers are approved for NOMID and JAK-inhibitors show efficacy in CANDLE treatment.Objectives:We used proteomic analysis to compare differentially expressed proteins in active NOMID and CANDLE compared to healthy controls before and after treatment, and whole blood bulk RNA seq to identify the immune cell signatures.Methods:Serum samples from active NOMID (n=12) and CANDLE (n=7) before and after treatment (table 1) and age matched healthy controls (HC) (n=7) were profiled using the SomaLogic platform (n=1125 proteins). Differentially expressed proteins in NOMID and CANDLE were ranked after non-parametric tests for unpaired (NOMIDp<0.05, CANDLE,p<0.1) and paired (p<0.05) analysis and assessed by enriched Gene Ontology pathways and network visualization. Whole blood RNA seq was performed (NOMID=7, CANDLE=7, Controls =5) and RPKM values were used to assess immune cells signatures.Table 1.Patient’s characteristicsNOMIDN=12, Male =6CANDLEN=7, Male =6AgeMedian (range)12 (2, 28)16 (3, 20)Ethnicity%White (Hispanic)80 (20)100 (30)GeneticsNLRP3mutation(2 Somatic, 10 Germline)mutations in proteasome component genes(1 digenic, 6 Homozygous/compound Heterozygous)Before treatmentAfter treatmentBefore treatmentAfter treatmentCRPMedian (range) mg/L52 (16-110)5 (0-23)5 (0-101)1 (0-4)IFN scoremedian (range)0NA328 (211-1135)3 (0-548)Results:Compared to control, 205 proteins (127 upregulated, 78 downregulated) were significantly different at baseline in NOMID, compared to 163 proteins (101 upregulated, and 62 downregulated) in CANDLE. 134 dysregulated proteins (85 upregulated, 49 downregulated) overlapped in NOMID and CANDLE (Figure 1). Pathway analysis identified neutrophil and monocyte chemotaxis signature in both NOMID and CANDLE. NOMID patients had neutrophilia and active neutrophils. CANDLE patients exhibited active neutrophils in whole blood RNA. Endothelial cell activation was the most prominent non-hematopoietic signature and suggest distinct endothelial cell dysregulation in NOMID and CANDLE. In NOMID, the signature included neutrophil transmigration (SELE) endothelial cell motility in response to angiogenesis (HGF, VEGF), while in CANDLE the endothelial signatures included extracellular matrix protein deposition (COL8A) suggesting increased vascular stiffness. CANDLE patients had higher expression of Renin, 4 out of 7 had hypertension, NOMID patients did not have hypertension. Treatment with anakinra and baricitinib normalized 143 and 142 of dysregulated proteins in NOMID and CANDLE respectively.Conclusion:Differentially expressed proteins in NOMID and CANDLE are consistent with innate immune cell activation. Distinct endothelial cell signatures in NOMID and CANDLE may provide mechanistic insight into differences in vascular phenotypes. Treatment with anakinra and Baricitinib in NOMID and CANDLE leaves 30% and 13% of the dysregulated proteins unchanged.Acknowledgments:This work was supported by Intramural Research atNational Institute of Allergy Immunology and Infectious Diseases of National Institutes of Health, Bethesda, Maryland, the Center of Human Immunology and was approved by the IRB.Disclosure of Interests:None declared


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