Biology subjects

Suff, N.

Publications and source records attributed to Suff, N..

4 recordsLinked to original sources

bioRxiv2023

Ascending vaginal infection in mice induces preterm birth and neonatal morbidity

Preterm birth (PTB; delivery <37 weeks), the main cause of neonatal death worldwide, can lead to adverse neurodevelopmental outcomes, as well as lung and gut pathology. PTB is commonly associated with ascending vaginal infection. Previously, we have shown that ascending E. coli infection in pregnant mice induces PTB and reduces pup survival. Here, we demonstrate that this model recapitulates the pathology observed in human preterm neonates, namely neuroinflammation, lung injury and gut inflammation. In neonatal brains, there is widespread cell death, microglial activation, astrogliosis and reduced neuronal density. We also validate the utility of this model by assessing efficacy of maternal cervical gene therapy with an adeno-associated viral vector containing human beta defensin 3; this improves pup survival and reduces Tnf mRNA expression in perinatal pup brains exposed to E. coli. This model provides a unique opportunity to evaluate the therapeutic benefit of preterm labour interventions on perinatal pathology.

neuroscience↗

bioRxiv2019

Cervical gene delivery of the antimicrobial peptide, Human β-defensin (HBD)-3, in a mouse model of ascending infection-related preterm birth

Approximately 40% of preterm births are preceded by microbial invasion of the intrauterine space: ascent from the vagina is the most common pathway. Within the cervical canal, antimicrobial peptides and proteins (AMPs) help to constitute a barrier which prevents ascending infection. We investigated whether expression of the AMP, human {beta}-defensin-3 (HBD3), in the cervical mucosa prevented bacterial ascent from the vagina into the uterine cavity of pregnant mice. An adeno-associated virus vector containing both the HBD3 gene and GFP transgene (AAV8 HBD3.GFP) or control (AAV8 GFP), was administered intravaginally into E13.5 pregnant mice. Ascending infection was induced at E16.5 using bioluminescent E.coli (E.coli K1 A192PP-lux2). Bioluminescence imaging showed bacterial ascent into the uterine cavity, cellular events that led to premature delivery and a reduction in pups born alive, compared with uninfected controls. In addition, a significant reduction in uterine bioluminescence in the AAV8 HBD3.GFP-treated mice was observed 24 hours post-E.coli infection, compared to AAV8 GFP treated mice, signifying reduced bacterial ascent in AAV8 HBD3.GFP-treated mice. There was also an increase in the number of living pups in AAV HBD3.GFP-treated mice. We propose that HBD3 may be considered a possible candidate for augmenting cervical innate immunity to prevent ascending infection-related preterm birth.

immunology↗

bioRxiv2018

Gene therapy in argininosuccinic aciduria

Argininosuccinate lyase (ASL) belongs to the liver-based urea cycle detoxifying ammonia, and the citrulline-nitric oxide cycle synthesising nitric oxide (NO). ASL-deficient patients present argininosuccinic aciduria characterised by hyperammonaemia and a multi-organ disease with neurocognitive impairment. Current therapeutic guidelines aim to control ammonaemia without considering the systemic NO imbalance. Here, we observed a neuronal disease with oxidative/nitrosative stress in ASL-deficient mouse brains. A single systemic injection of gene therapy mediated by an adeno-associated viral vector serotype 8 (AAV8) in adult or neonatal mice demonstrated the long-term correction of the urea cycle and the citrulline-NO cycle in the brain, respectively. The neuronal disease persisted if ammonaemia only was normalised but was dramatically reduced after correction of both ammonaemia and neuronal ASL activity. This was correlated with behavioural improvement and a decrease of the cortical cell death rate. Thus, the cerebral disease in argininosuccinic aciduria involves neuronal oxidative/nitrosative stress not mediated by hyperammonaemia, which is reversed by AAV gene transfer targeting the brain and the liver, acting on two different metabolic pathways via a single vector delivered systemically. This approach provides new hope for hepatocerebral metabolic diseases.

genetics↗

bioRxiv2018

Generation of light-producing somatic-transgenic mice using adeno-associated virus vectors

We have previously designed a library of lentiviral vectors to generate somatic-transgenic rodents to monitor signalling pathways in diseased organs using whole-body bioluminescence imaging, in conscious, freely moving rodents. We have now expanded this technology to adeno-associated viral vectors. We first explored bio-distribution by assessing GFP expression after neonatal intravenous delivery of AAV8. We observed widespread gene expression in, central and peripheral nervous system, liver, kidney and skeletal muscle. Next, we selected a constitutive SFFV promoter and NF{kappa}B binding sequence for bioluminescence and biosensor evaluation.\n\nAn intravenous injection of AAV8 containing firefly luciferase and eGFP under transcriptional control of either element resulted in strong and persistent widespread luciferase expression. A single dose of LPS-induced a 10-fold increase in luciferase expression in AAV8-NF{kappa}B mice and immunohistochemistry revealed GFP expression in cells of astrocytic and neuronal morphology. Importantly, whole-body bioluminescence persisted up to 240 days.\n\nTo further restrict biosensor activity to the CNS, we performed intracerebroventricular injection of each vector. We observed greater restriction of bioluminescence to the head and spine with both vectors. Immunohistochemistry revealed strongest expression in cells of neuronal morphology. LPS administration stimulated a 4-fold increase over baseline bioluminescence.\n\nWe have validated a novel biosensor technology in an AAV system by using an NF{kappa}B response element and revealed its potential to monitor signalling pathway in a non-invasive manner using a model of LPS-induced inflammation. This technology employs the 3Rs of biomedical animal research, complements existing germline-transgenic models and may be applicable to other rodent disease models with the use of different response elements.

genomics↗