Relatively little is known about the transgenerational effects of chronic maternal exposure to low-level traffic-related air pollution (TRAP) on the offspring lung health, nor are the effects of removing such exposure before pregnancy. Female BALB/c mice were exposed to PM_2.5 (PM_2.5, 5 µg/day) for 6 weeks before mating and during gestation and lactation; in a subgroup, PM was removed when mating started to model mothers moving to cleaner areas during pregnancy to protect their unborn child (Pre-exposure). Lung pathology was characterised in both dams and offspring. A subcohort of female offspring was also exposed to ovalbumin to model allergic airways disease. PM_2.5 and Pre-exposure dams exhibited airways hyper-responsiveness (AHR) with mucus hypersecretion, increased mitochondrial reactive oxygen species (ROS) and mitochondrial dysfunction in the lungs. Female offspring from PM_2.5 and Pre-exposure dams displayed AHR with increased lung inflammation and mitochondrial ROS production, while males only displayed increased lung inflammation. After the ovalbumin challenge, AHR was increased in female offspring from PM_2.5 dams compared with those from control dams. Using an in vitro model, the mitochondria-targeted antioxidant MitoQ reversed mitochondrial dysfunction by PM stimulation, suggesting that the lung pathology in offspring is driven by dysfunctional mitochondria. In conclusion, chronic exposure to low doses of PM_2.5 exerted transgenerational impairment on lung health.

In humans, maternal particulate matter (PM) exposure during pregnancy is known to negatively affect offspring’s lung. Most murine models used to investigate mechanisms with high doses. The aim of this study was to develop a low dose in-utero exposure model to investigate the effect on offspring’s lung health. Female BALB/c mice were divided into SHAM, PM and PM cessation groups. PM group was exposed to PM1 (5ug/day) before mating for 6 weeks, during gestation and lactation. PM cessation group only exposed during the pre-gestational period. Lung were collected from both dams and male offspring at age of postnatal day P1, P20 and 13 weeks. Lung function were tested in the dams and bronchoalveolar lavage fluid was assessed for inflammation. Oxidative stress (MnSOD), mitophagy (Drp-1, Opa-1, Parkin1 and PINK1), autophagy (LC3A/B-I, II), pro-inflammatory mediator (NF-KB, MAPK signalling pathway (ERK1,2, JNK1,2 and P38)), and inflammasome NLRP3 were measured by western blotting. In the dams, PM exposure caused airway hyperresponsiveness and increased infiltration of macrophages and neutrophils into the lung. This was accompanied by increased oxidative stress, inflammasome, autophagy and MAPK siganaling pathway activation, some of which were reduced in the ceseation group. In P1 and P20 offspring, Mitophagy and MAPK signalling casecades markers were increased by maternal PM exposure, which were reduced in the ceseation group. At 13 weeks, the offspring from PM exposed dams had more macrophages in the BALF. p-JNK2 level in the PM group was higher than the SHAM. Compared to the PM group, PM cessation group had lower Drp-1. Conclusion: PM exposure caused adverse effects in the lungs of dams and offspring.

Traffic-related air pollution induces mitochondrial oxidative stress and transgenerational mitochondrial dysfunction Background: Exposure to Traffic-Related Air Pollution (TRAP) during pregnancy increases the risk of respiratory diseases in offspring, but the mechanisms are not well understood. The mitochondria produce ATP through oxidative phosphorylation, but can also be the source of excessive reactive oxygen species (ROS) in response to external stimuli. Methods: Female BALB/c mice were exposed to TRAP particulate matter (PM2.5, 5 µg/day) for 6 weeks before mating and during gestation and lactation. ROS levels and mitochondrial functional markers were characterised in the lung tissues. Mitochondrial function was analysed with the seahorse analyser in airway epithelial Beas-2B cells treated with TRAP PM2.5. Result: Maternal PM exposure induced hyper-responsiveness in both dams and female offspring. In the dams, the total ROS level was significantly increased in the PM groups. The mitophagy fission marker dynamin-related protein 1 (Drp-1) level was significantly decreased in the PM group followed by the lower mitofusin degradation marker parkin level. In the female offspring, the mitochondrial density, mitochondrial ROS and total ROS level in the lung were significantly increased in the PM group accompanied with higher Drp-1 level and lower parkin level. The mitochondria-targeted antioxidant MitoQ reversed mitochondrial dysfunction by PM stimulation in the Beas-2B cells. Conclusion: Maternal PM exposure induced transgenerational hyper-responsiveness and is highly associated with mitochondrial dysfunction. Mitochondrial dysfunction is driven by oxidative stress.

Cigarette smoke exposure (SE) during pregnancy is the largest modifiable risk factor for the development of asthma. We have previously shown that maternal L-Carnitine treatment reduces renal and brain adverse impacts in SE offspring, but its effect on the lung is unknown. Here, in order to investigate the effect of maternal L-Carnitine supplementation on lungproinflammatory signalling pathwayswe measured inflammasome NLRP3 activation, signalling pathway activation (ERK1,2, JNK1,2, MAPK, and NF-KB), and markers of autophagy (LC3A/B-I, II) and mitophagy (Drp-1 and Opa-1). Female Balb/c mice (8 weeks) were exposed to cigarette smoke before mating for 6 weeks, during gestation and lactation. Half SE mothers were given L-Carnitine supplementation through drinking water during gestation and lactation. Lung samples were collected at postnatal day 1 and 13 weeks from both male and female offspring. At P1, there was an increase in phospho-ERK1,2, total ERK1,2, total JNK1,2, phospho-P38 MAPK and P38 MAPK, phospho-NFKB, NFKB and NLPR3 protein levels in male offspring. The mitochondrial fission marker Drp-1 and autophagosome markers (LCA3A/B-I,II) were increased in SE offspring, L-Carnitine significantly reduced protein levels of phospho-ERK1 and Drp-1. At 13 weeks, there was an increase in autophagosome markers (LCA3A/B-I,II) and MAPK signaling pathway markers (phospho-ERK2, total ERK2, total P38 MAPK and phospho-NFKB), which were partially normalized by L-Carnitine treatment. Maternal SE did not affect the female offspring with no changes found after L-Carnitine treatment. L-Carnitine supplementation during pregnancy may alleviate the adverse impact of maternal smoking in the male offspring’s lung.