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Microbes & Immunity Understanding lung development, health, and diseases

idiopathic pulmonary fibrosis (IPF), chronic obstructive include congenital pulmonary airway malformation (CPAM),
pulmonary disease (COPD), bronchopulmonary dysplasia bronchopulmonary sequestration (BPS), bronchogenic cysts,
(BPD), and pulmonary hypertension. They are impacted bronchial atresia, congenital lobar emphysema (CLE), and
by environmental factors like oxidative stress, infections, congenital tracheal obstruction.
and aging. 27
3.1. CPAM
Lung myofibroblast differentiation has been
demonstrated to be altered by histone deacetylases CPAM is a developmental anomaly of the lower respiratory
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(HDACs). A study involving profibrotic fibroblast tract. Formerly known as congenital cystic adenomatoid
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phenotypes, derived from IPF patient fibroblasts and a malformation, CPAM is a benign lung disorder marked
murine model of lung fibrosis, showed that epigenetic by the presence of cystic lesions. It is the most prevalent
modification of the Fas promoter through histone cystic lung lesion detected prenatally, typically between
acetylation is associated with altered expression of HDAC2 18 and 20 weeks of gestation. It accounts for about 95% of
and HDAC4. Moreover, profibrotic fibroblasts treated with congenital cystic lung diseases. Since the advent of prenatal
HDAC inhibitors had higher expression of Fas and were ultrasound, previously unidentified lesions are now more
more susceptible to Fas-mediated apoptosis. HDACs are frequently identified. Hence, it is likely that the actual
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members of a broad family of multiprotein complexes that prevalence has been underestimated. The treatment of
regulate various biological processes. The Fas promoter asymptomatic CPAMs remains under discussion, whereas
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modification indicates a potential way to identify or modify the management of symptomatic CPAMs is generally well-
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the regulatory elements that govern Fas gene expression, established.
which produces a cell surface protein involved in apoptotic 3.2. BPS
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signaling. In addition, oxidative stress induced by factors
such as cigarette smoke, environmental pollutants, and BPS is an uncommon condition characterized by non-
aging can alter chromatin folding and gene expression. functioning lung tissue that is detached from the main
The disruption which involves HDACs and histone bronchial tree and may obtain blood supply from the
acetyltransferases (HATs) contributes to inflammation, systemic circulation. Such aberrant tissue frequently leads
impaired autophagy, and cellular senescence, especially in to recurrent respiratory infections and typically requires
COPD. 32 surgical removal. 38,39 The intralobar type is defined and
distinguished by the aberrant lung tissue located within the
The acetylation of lysine residues, especially those normal lung and sharing its visceral pleura, whereas the
located in the N-terminal of core histones, is controlled extralobar type possesses its own distinct pleural covering.
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by two opposing enzyme families, such as HDACs Several percutaneous prenatal intervention procedures
and HATs. HDACs are essential for host defense by have been found to improve perinatal outcomes for large
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promoting pro-inflammatory responses. However, certain lesions linked to hydrops. These consist of intratumor
HDACs can also reprogram macrophages and monocytes sclerosant injections, thoracocentesis, thoraco-amniotic
to exhibit immunosuppressive characteristics. Histone shunt insertion, and combined therapeutic approaches.
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acetylation affects chromatin structure and, consequently, Although hydropic fetuses are rare and evidence of the
gene expression. In addition to histones, certain lysine condition remains limited, it is evident that intrusive
residues in non-histone proteins can also undergo therapy can provide significant benefits. 41
acetylation, which affects the stability and biological roles
of these proteins. Monocytes must maintain a proper 3.3. Bronchogenic cysts
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balance in acetylation dynamics to respond to numerous Bronchogenic cysts are congenital abnormalities
physiological and pathological stimuli. Notably, aberrant originating from the tracheobronchial tree and foregut,
expression or activity of specific HDACs has been best known as intrapulmonary bronchogenic cysts. These
associated with various chronic inflammatory illnesses, rare cystic anomalies of the respiratory system typically
including autoimmune disorders, infections, and cancer. 30 develop early in gestation within the mediastinum, while

3. Lung developmental disorders later in gestation, they are more likely to arise in the
thoracic cavity. Nevertheless, they may originate anywhere
Congenital lung disorders are the outcome of aberrant along the foregut. The identification of these cysts can
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embryonic development, often caused by disturbed signaling be difficult due to their diverse clinical and radiologic
pathways or genetic factors. These deformities include a characteristics, especially in areas where hydatid disease
variety of anatomical abnormalities affecting the lungs and is prevalent. Despite complications like infection may
respiratory tract. Common congenital lung disorders occur, endoscopic drainage has been investigated as
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Volume 2 Issue 3 (2025) 50 doi: 10.36922/mi.7719