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Abstract
Gene therapy is a growing field in research and development that may 
offer a long-lasting solution to several complex diseases, including 
chronic obstructive pulmonary disease (COPD). COPD is characterized by 
chronic inflammation in the lungs and the airways, leading to respiratory 
problems. COPD includes chronic bronchitis and emphysema. Optimizing 
treatments for gene therapy in COPD is of paramount importance given 
COPD's prominence as the fourth leading cause of disease-related death in 
the United States. We reviewed delivery methods in the current research, including 
liposomes, nanoparticles, electroporation, adeno-viruses, and adeno-associated 
viruses (AAV). The broad customizability in the diagnostic and treatment 
methods is evident in the recent studies. In this paper we explore each method 
and/or biomarker and evaluate several gene therapy avenues for COPD.

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Background

Chronic obstructive pulmonary disease, also known as COPD, is 
characterized as a chronic in�ammatory lung disease that causes obstructed 
air�ow from the lungs. It includes multiple progressive lung diseases that 
a�ect millions of people yearly. In 2018, COPD was the fourth leading 
disease related cause of death in the United States, 6.4% of Americans were 
diagnosed with the disease, unfortunately, this number is likely higher due 

to undiagnosed cases1.

Figure 1: Diagram of the lungs and the effect chronic bronchitis and emphysema has on 
them. Boxed under chronic bronchitis are images of healthy (A) and unhealthy (B) bronchial 
tubes, (B) shows the inflammation and increased mucus in the unhealthy bronchial tubes. 
Boxed under emphysema are images of the alveoli, healthy (A) and unhealthy (B). In the 
unhealthy (B) image there is a membrane breakdown due to inhaled pollutants that causes 

larger sacs with a decreased surface area.

COPD is not caused by a single gene or factor, this makes a single treatment 
for all patients less e�ective, and makes an appeal towards a more 
personalized treatment1. Two of its major contributors include 
emphysema and chronic bronchitis. Chronic bronchitis is characterized by 
the in�ammation of the bronchial tube lining and excess mucus 
production, the bronchial tubes are responsible for carrying air to and from 
the air sacs (alveoli) within the lungs. Emphysema is a condition in which 
the alveoli membranes are destroyed due to chronically inhaled pollutants. 
The membrane breakdown creates larger air sacs rather than smaller ones,

Berkeley Pharma Tech Journal of Medicine | 59



this decreases the surface area and the amount of oxygen that can di�use 
into the blood.

There are many factors that cause the development and progression of 
COPD, the main factors include cigarette smoke and work-related 
pollutants2. COPD is also considered to be inheritable, as there are 
genetic components that can play a role in disease development. The �rst 
gene identi�ed to be associated with COPD was SEROINA, which encodes 
alpha1-antitrypsin (A1AT). De�ciencies in A1AT can lead to emphysema, 
but only 1-3% of COPD patients have the de�ciency. Additionally, it has 
been recently discovered that altered miRNA expression in the lungs might 
also play a role in the COPD mechanism. The characteristic symptoms that 
de�ne COPD include the following: breathing di�culty, coughing, 
wheezing, oxidant/antioxidant imbalance, emphysema (alveolar wall 
destruction), mucus hypersecretion, enhanced cytokines, chemokines, 
protease, and in�ammation3.

Current conventional therapeutic strategies of COPD utilize antioxidant 
and anti-in�ammatory drugs3. These drugs tend to be bronchodilators, such 
as β-agonists and muscarinic antagonists, and inhaled corticosteroids, both 
of which are only used for short-term management. These treatments only 
target the patient’s symptoms, and do not stop or reverse damage to the 
lungs2. Bronchodilators, such as β-agonists and muscarinic antagonists work 
to relax the muscles in the lungs to alleviate coughing and make breathing 
easier, whereas inhaled steroids reduce airway in�ammation and help 
prevent exacerbations. Working towards a treatment for COPD that could 
prevent or reverse lung damage, would impact the lives of millions. Gene 
therapy is an attractive alternative to current treatments, it is able to deliver 
medications and therapeutics to speci�c target sites within the lungs. 
However, it's important to note that there are limitations due to various 
biological barriers. These limitations can include; o�-target vector e�ects, 
genetic material, and delivery e�cacy1.

Due to the variety of infections causing diseases in the respiratory system, 
there are only 17 FDA approved treatments available for patients, none of 
which treat lung diseases1. ABECMA is an example of an approved gene

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therapy that treats multiple myeloma, a disease where the body’s white 
blood cells proliferate and cause harmful build ups throughout the body.

This speci�c gene therapy modi�es the patient’s T-cells to attack the 
cancerous white blood cells4. Another example includes Luxturna, a viral 
vector gene therapy form that treats congenital blindness. Most patients 
with congenital blindness contain a mutation in the RPE65 gene, which 
produces the chromophore 11-cis retinal protein that is vital for eye 
function. Luxturna works by delivering functional copies of the RPE65 
gene to the retinal epithelial cells5.

Cystic Fibrosis (CF) is a common candidate for gene therapy research and 
can o�er some insight in the treatment of COPD as well. Due to defective 
sodium/potassium ion channels in the ciliated cells, the airway becomes 
dehydrated and starts secreting more mucus which is a breeding ground for 
infection-causing bacteria. Because of the fatality of the airway obstruction, 
doctors are researching to replace the CFTR gene during the neonatal 
period to maximize the success of the therapy and the patients’ quality of 
life6. To deliver the CFTR gene into the lung, scientists have 
experimented with the oral inhalation of aerosolized vectors using a 
nebulizer rather than a liquid �lled nasal tube. This method of delivery 
reduces the risk of aspiration and could be useful when treating other lung 
diseases, including COPD6. Modulator therapies are also burgeoning 
methods to treat CF, and each therapy targets a speci�c mutation in the 
CFTR gene. The success of the modulator therapy was shown in a research 
study when 55% of the subjects experienced signi�cant decrease in 
P.aeruginosa7.

Genes that contribute to COPD such as SERPINA1 that causes an α-1 
antitrypsin de�ciency would be a good candidate gene for potential 
modulator therapies with certain mutations in the gene8. Recent genetic, 
biochemical and histological evidence also suggests altered transforming 
growth factor beta (TGF-β) signaling is associated with COPD 
development and progression. TGF-β regulates the respiratory system and 
can lead to diseases if it is mutated. Subduing altered TGF-β signaling in the 
airways and alveolar sacs via gene silencing technologies may provide similar

Berkeley Pharma Tech Journal of Medicine | 61



therapeutic outcomes to modulator therapies and other treatment 
options9.

Deliveries

The development in gene therapy for COPD hinges on several factors, one 
of the most prominent of which is delivery method to ensure e�cacy and 
precision in use of the particular therapy. Delivery methods must optimize 
performance and transfection as well as safety both for the patient and 
protection of genetic material. Even in common inhalable drug delivery, 
limitations are present due to the complex defense mechanisms of the 
respiratory system. These factors are limited in e�cacy and primarily focus 
on airway obstruction via anticholinergics and dual β2-dopamine 2 receptor 
antagonists10.

Techniques used for gene therapy can be separated into 3 major categories: 
chemical, physical, and viral. Chemical techniques entail the non-viral 
methods for creating materials and particles used to transfect or insert 
genetic material into the target cells. This can be achieved in several ways 
whether it be to weaken the cell function or to create new vectors that take 
advantage of common cellular functions and mechanisms, such as 
liposomes and nanoparticles (NPs). Next, physical techniques revolve 
around mechanical methods to typically achieve new access points or alter 
the function of the cell slightly without introducing a chemical alteration or 
manipulation to the equation. Increasing the permeability and uptake of 
genetic material of the cell or direct injection is the most common 
mechanism in which these methods are able to insert the genetic material. 
The more prominent of these is a shock treatment to open the cell 
membrane for a brief period of time known as electroporation (EP). 
Thirdly, viral delivery methods are created by modifying viral genomes to 
take advantage of viral mechanisms of inserting genetic material. The most 
common vectors that have extended into the realm of gene therapy for 
pulmonary diseases are EP, liposomes, viral vectors, and NPs. Each of the 
aforementioned methods give way to their own advantages and problems; 

seen in Figure 2, thus validating the need for further research on gene 
therapy for symptoms of COPD. [JG1] Longevity and �nding the ideal 
carrier to inhibit the e�ects of COPD using these treatments is necessary to

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counteract the lifelong e�ects traditionally associated with it and other
commonplace pulmonary diseases.

Figure 2: Modeled from diagram of delivery method choice for gene therapy 
in the lungs [1]. The more generally observed shortcomings and advantages of 
each key delivery method to be discussed in detail. Individual modifications, 
especially in the case of liposomes and NPs, can be made to better these such as 
particle coating and more effective targeting mechanisms.

Non-Viral Methods

Liposomes

Taking advantage of natural lipid bilayers to employ liposomes with genetic 
material, lipoplexes, for delivery cargo to cells utilizing endogenous 
functions of the cell membrane is one of the primary strategies in gene 
therapy for COPD. The most glaring functional advantage of lipofection as 
a technique is the lack of immune response and cytotoxicity upon 
transfection that has been observed11,12. In addition to this, low cost and 
ease of use make liposome based gene therapy a preferred treatment. 
Morphology which mimics that of cell membranes’ lipid bilayer can be 
modi�ed with targeting molecules to adhere to di�erent cells with more 
precision and limited collateral damage. The accepted but not completely 
understood mechanism of action takes advantage of random Brownian 
motion of the liposomes upon entrance into the cell to e�ectively disperse 
the material13. In generic drug delivery this allows for seamless
in�ltration and dosing of the cell. However, the speci�city of gene delivery

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requires nuclear transport of the contained genetic material; these 
shortcomings can be observed through endocytosis inhibitors and 
endosome trackers to visualize delivery sites14.

The endogenous nature of liposomes is massively important for pulmonary 
diseases and speci�cally COPD where constant in�ammation and 
exacerbations take place regularly. A well observed phenomena since the 
1970s, liposomal immunogenicity, can be built upon even further to trigger 
minimal immune responses. For example, liposomes for drug delivery that 
showed an inverse correlation with immunoglobulin (IgM) in the brain 
were modi�ed to enhance absorption of IgM and thus the immune 
response and overall e�ectiveness of the treatment was improved15. Relative 
to the lungs, clinical trials have utilized lipoplexes in tandem with a plasmid 
carrying human CFTR in inhalable doses to limit mucus problems in 
patients with CF, a common comorbidity of COPD16.

The bene�ts of these native characteristics of liposomes are signi�cant but 
can present their own pitfalls as well which must be monitored. Natural 
mechanisms can act as impediments to treatments such as the bovine 
pulmonary surfactant Alveofact have been shown to weaken

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Figure 3: Image shows the mechanism by which liposomes (and some NPs) 
can introduce genetic information into a cell by taking advantage of 
endocytosis, a natural cell mechanism, and limiting the immune response–
thanks to the endogenous nature of the liposomal structure and makeup.

several types of lipoplexes17. Overcoming these innate obstacles while 
maintaining the key bene�ts of lipoplex usage is of paramount importance 
and needs more research to fully understand the functionality in di�erent 
cell types within the pulmonary system. Speci�c work with cells and the 
mechanisms of the pulmonary system will yield a better understanding of 
how lipofection can be used as a widespread treatment.

Nanoparticles

NPs (nanoparticles) are a massive and growing �eld of research for a 
number of possibilities including gene therapy for the lungs. Nanoparticles 
for gene therapy can be characterized by submicron sized particles that

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optimize surface to volume ratios while maintaining good performance of 
biocompatibility and biodegradation3. The customizability of NPs for 
di�erent cell types, degrees of accumulation, and degradation o�er several 
advantages as carriers for gene therapy treatment in the pulmonary system. 
Taking advantage of endocytosis and permeability factors of cells in similar 
manner as lipoplex-based techniques, NPs can utilize similar lipid based 
qualities but are ultimately de�ned by size and their diverse makeup which 
extends beyond liposomes.

Targeting cells and material within the airways limits the abilities to 
penetrate into the tissue for many delivery methods. As mentioned, 
liposomes can encounter problems with penetrating surfactant and mucosal 
layers due to degradation and dissociation. Modi�cations can be made to 
NPs to resist mucoadhesion and trapping or degradation that may otherwise 
occur. One of the most common methods for this is a coating of 
polyethylene glycol (PEG) polymer to provide a hydrophilic and neutral 
coating to counteract traditional charge based dynamics used in synthesis18. 
It has been found that these PEG coatings provide varying levels of 
improvement in penetration of the thick mucus that exacerbates the issue of 
access to airway epithelial cells in patients with advanced COPD; degraded 
structures such as neutrophils and dense meshes of highly negative charged 
structures create a less permeable mucus layer19,20.

These �ndings further the ability to overcome airway mucus, one of the 
primary issues in inhalable gene therapy to treat COPD and prevent
signi�cant worsening of symptoms.

PLGA

A candidate in gene therapy using NPs is that of poly
((d,l-lactide-co-glycolide) (PLGA)) based nanoparticles. PLGA-NPs are 
FDA and European Medicine Agency approved for drug delivery systems, 
not gene delivery. Good results have been demonstrated regarding 
biocompatibility that exceeds that of common liposome based treatments in 
transfection of HepG2 cells for gene delivery21,22. Surface modi�cations can 
be made to PLGA-NPs to enhance e�ciency in performance such as the 
addition of polyethyleneimine (PEI) made by Bivas-Benita et al. to enhance 
performance in the pulmonary system given its merits as a gene delivery

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vector; the particles were seen to escape the endolysosomal envelope and 
subsequent damage to continue release of material in some instances as 
well23.

Dendrimers

A relatively unique NP structure that has gained exposure in gene therapy 
treatment given success in diagnostics is dendrimers. These NPs are based 
on the dendrimer polymers that exhibit a radially symmetric pattern of 
branching chains. This allows for many exposed ends at the surface that can 
be modi�ed much like other NPs to optimize their function as a delivery 
method for genetic material. Hypotheses revolve around the potential for 
these large amounts of ionizable branches to be modi�ed, most commonly 
utilizing poly-(amidoamine) and poly-(propyleneimine) as a base, or 
immediately paired with genetic material for testing29. To help in structure 
stability and formation the aforementioned PEG coating is applied to 
dendrimer NPs prior to material attachment1. Given the plentiful terminals, 
rapid absorption and dissipation of the NPs is another problem solved via 
these PEG coatings by enhancing retention by the lung tissue. The majority 
of the published work on dendrimer NPs in lung tissue gene therapy 
presents them in the context of this ‘PEGylation” given the ability to 
control uptake with a much higher degree of precision than without30,31. 
Dendrimers share in the success of NPs as a whole in their continued 
research and have signi�cant potential for delivery of gene therapy to inhibit 
COPD symptoms provided the state of knowledge continues to advance.

Electroporation

Electroporation (EP) di�ers from previously discussed delivery methods 
in its physical based mechanism of action rather than the chemical basis 
on which NPs and lipoplex therapies rely. It has emerged as one of the 
few physical methods researched for gene delivery given its safety and 
e�cacy compared to others. EP takes advantage of an electric �eld 
applied across cells to alter permeability and allow previously injected 
genetic material to be more readily endocytosed. Transfection e�ciency in 
tumors using EP has provided the foundation of knowledge for its usage in 
lung tissues. Intense

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tissue analysis and/or electric �eld testing is required in most cases to ensure 
optimal settings given the natural variation in biological tissues32. 
Traditional chemical based approaches make up the vast majority of 
research due to customizability. However, as these �elds move forward 
experiments have validated EP as a comparably e�ective method when 
physiological responses are considered in tandem with pure gene expression 
amongst cells33.

Viral Methods

Viral vectors have been researched as avenues for gene therapy for years now 
given their development in the early 1970s and 80s and ability to take 
advantage of mechanisms native to the viruses themselves. The primary 
vector types found in modern gene therapy for COPD and lung tissue 
oriented studies are adenovirus and adeno-associated virus (AAV) based 
approaches. The di�erences in viral vectors and e�cacy is contingent on the 
exact protein capsid and tissue tropism, the gene of interest for therapeutic 
purposes, and the alterations that control the gene expression for the 
vector34. These work together and can be chosen or altered to perfect one’s 
vector for its desired purpose. Common problems brought about in viral 
vector usage despite modi�cations is the innate immune response. T-cell 
responses and toxicity within tissue is a cause of viruses that has developed 
to help the body respond. However, redesign and manipulation of these 
viral genomes and bodies can still carry markers to inhibit their expression 
when used as vehicles for gene therapy.

Adenoviruses

With regard to the aforementioned characteristics adenoviruses are a family 
of icosahedral nucleocapsid viruses. They are unenveloped and hence carry 
their genetic material, double stranded DNA, within this characteristic 
icosahedral chamber. Adenoviruses account for several acute respiratory 
illnesses and human adenoviruses (HAdVs) have a wide range of categorized 
species based on key characteristics that number over 80 types35. Work in 
gene therapy for COPD stems from HAdVs’ versatile tissue tropism and 
prevalence in lung-related diseases and replication36. Imaging techniques

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have revealed signi�cantly higher carrying capacity for genetic material in 
adenoviruses than alternative viral vector platforms at around 36 kb pairs 
while delivering roughly 8 kb pairs. A capacity that can be increased using a 
newer generation of helper-dependent adenoviruses (HD-AdVs) by deleting 
the viral coding sequences1,37-38. Such delivery methods have been used in 
gene delivery to pig airway epithelia to demonstrate delivery of the CFTR 
protein in hopes to reverse mucus production and in�ammation in patients 
with cystic �brosis and associated lung diseases39.

As prominent viruses in everyday life a common phenomena observed in 
usage of AdVs for clinical trials is pre-existing immunity 40 which presents 
the need for research of multiple HAdV serotypes to allow for versatility in 
practical usage as gene vectors. AdV types that rely on a singular method of 
cell entry have limited access points and see more pre-existing immunity. As 
previously mentioned, HAdVs types are plentiful and subcategorized into 7 
grand species A-G, the majority of which belong to the HAdV-D family40. 
HAdV-D type 49 is one of many HAdV types that utilize varying surface 
molecules to enter the cell and as a result is a prime candidate for research in 
AdV vectors to solve this issue of immunity. The viability of HAdV-D49 is 
compounded by its observed transduction in lung and spleen tissues while 
showing reduced targeting in liver and other less desirable tissues when 
looking at in vivo biodistribution41. Immune response has also been 
mitigated by using HD-AdV vectors as their stripped down genome 
removes key markers for the immune system to identify and target. Airway 
basal cells of mice and pigs have been targeted successfully using these HD-
AdVs following intranasal delivery42,43. Limiting immune response while 
maintaining a focus on the e�cacy of AdV based gene therapy is the current 
objective that needs �ne tuning in research for AdV vectors to obtain 
signi�cant clinical success.

Adeno-associated viruses

To build upon the problem of immune response many relatively distant 
derivatives of AdV virus vectors have been created known as
adeno-associated virus (AAV) vectors. These have more desirable 
immunogenicity. They evoke a weak in�ammatory response compared to

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AdV vectors by lacking a staple viral coding sequence and contain a linear 
single-stranded DNA. Behavioral di�erences in host integration led to its 
prevalence in research as an option for gene therapy.
Carrying capacity in AAV vectors is limited in comparison to AdVs at 
typically less than 5 kb though reports have seen up to ~9 kb of genome
e�ciently incorporated into AAV vectors for therapeutics44,45.

Increased packaging capacity typically comes at a cost of transduction rate 
and overall e�cacy in AAV vectors though research continues to be done to 
improve the most pressing drawback of the delivery method. Researchers at 
Stanford have altered charges in the lumen of AAV variants known as AAV-
DJ to transduce cells derived from human kidneys better than wildtypes 
when packed at a higher rate of up to 6.2 kb46. More akin to lung therapies 
for COPD, viral/AAV chimeric gene therapy has seen
signi�cant research in navigating human epithelial cells. Chimeric viral 
vectors look at combinations of multiple vector methods in hopes to take 
advantage of favorable characteristics in each and pose grounds for
signi�cant advancement in gene therapy for respiratory diseases given local 
cell selectivity. A type of chimera vector packaging plasmids using AAV and 
human bocaviruses (HBoV) been shown to work well in tandem with 
human airway epithelia, primary human hepatocytes, skeletal muscle cells, 
and T cells; in addition to good performance in extensive studies in ferret 
airway models more recently47,48. These AAV/HBoV combination vectors 
o�er a novel approach to creating vectors for gene therapy in treatment of 
COPD.

Potential Treatment

There are many limitations to modern gene therapies used today caused by 
many biological barriers. [JG1] Most lung-related therapies must pass through 
multiple barriers such as the mucus, pulmonary surfactant, and local
in�ammation24. This could cause a problem since patients with diseases 
such as asthma and cystic �brosis could also cause a biological barrier due to 
the airway mucus hypersecretion, which also plays a role in COPD, since 
around 50% of COPD patients have airway mucus hypersecretion25.

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Another limitation is when targeting JG3 cells other than the epithelium 
cells will cause the epithelium cells itself to become a major barrier24.

Although there are several limitations to current gene therapies, there are 
other alternatives to target cells that could be considered in treatments. For 
example, epithelial cells, alveolar cells, and macrophages all can be accessed 
through inhalation of nucleic acid containing nanoparticles (NANs)26. This 
method of treatment helps target the lung and not target other cells that 
could cause biological barriers. Although inhalation of nanoparticles seems 
like a great treatment for lung disorders, it is actually limited in some COPD 
treatments. The inhalation of BIBW 2948, which is used for treating 
COPD, helped reduce the internalization of EFGR, which plays an 
important role in epithelial changes in COPD, but does not reduce the 
mucin storage27,28.

BAMBI, which is the bone morphogenic protein and activin
membrane-bound inhibitor, plays an important role in indicating if a 
patient has COPD. BAMBI are expressed stronger in
COPD patients [28]. Also there is a correlation between the levels of 
BAMBI and plasma TGF -β1 levels. Therefore, the inhibition of TGF-β1 
signaling might provide an alternative therapeutic strategy for treating 
COPD28.

Inhale Gene Therapy

Another potential therapeutic treatment for COPD is through Inhaled 
Gene Therapy. This treatment provides direct access to the target of gene 
therapy for obstructive lung diseases via inhalation. There are limitations 
that surround inhale gene therapy. In a study conducted by Dr. Magdalena 
Humenberger from the Kepler University Hospital in Austria concluded 
that complete adherence to inhaled therapy was only seen in 33.6% and was 
higher among those with more severe COPD, based on these results47. It 
was shown that mucus poses a barrier for this speci�c treatment. Although 
this is a current problem, other studies have mentioned a di�erent type of 
gene vector that could be inhaled that would penetrate that mucus barrier. 
A type of nanoparticle that was introduced by

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Dr. Jung Soo Suk, from the The Center for Nanomedicine in the Johns 
Hopkins University School of Medicine, was the mucus-penetrating DNA 
nanoparticles (DNA-MPP), which possess non-adhesive coatings that allow 
them to rapidly penetrate mucus layers48. The PEG coating helps with the 
DNA-MPP treatment since it does not have a dense surface, helping the 
nanoparticle to penetrate other mucin-based meshwork48.

Stem   Cell       Therapy

Another potential way of treating COPD is through stem cell therapy. This 
treatment is considered one of the newer treatments that still has a lot of 
questions �oating around it. Although stem cell therapy is not considered 
safe, it still has potential when it comes to treating disorders such as COPD. 
Recently there have been several studies and clinical trials that have focused 
on stem cell treatment. The studies on COPD focused on a speci�c stem 
cell treatment called Mesenchymal Stem Cells (MSCs), which is important 
for making and repairing skeletal tissues49. In a clinical study, they were 
infused with expanded allogeneic umbilical cord tissue derived 
mesenchymal stem cells (MSCs) to 20 COPD patients and then were 
monitored for 6 months49. This study concluded a signi�cant improvement 
in some important outcomes of
COPD, including mMCR, CAT, number of symptoms, and the 
downregulation of in�ammation49. Although this study is considered a 
pilot study, a small scale clinical study, it provides a unique perspective 
when it comes to treating COPD via stem cell therapy.

Alpha1-antitrypsin

Alpha1-antitrypsin (A1AT) is a protease inhibitor whose de�ciency is most 
commonly associated with the ZZ mutation which causes abnormal folding 
in the ER of hepatocytes during biogenesis, causing its retention within the 
ER. The retention of 90% of the normal A1AT levels greatly increases the 
risk for early onset COPD50. In a large Lithuanian cohort, out of 1167 
patients who had COPD ranging from moderate to severe, 3.4% had the 
MZ mutation, 3.3% had the MS mutation, 0.3% had the SZ mutation, and 
0.7% had the ZZ mutations. Results from the screen indicated that there

Berkeley Pharma Tech Journal of Medicine | 72



was a signi�cant increase in MZ, SZ and ZZ genotypes in COPD patients; it 
also supported the concept of using a targeted screen for A1AT de�ciency 
when diagnosing COPD51. Another study conducted in Brazil on 926 
COPD patients found that 2.8% had A1AT de�ciencies and 0.8% had the 
ZZ mutation. These results also supported the importance of screening for 
A1AT levels in all COPD patients52.

miRNA

miRNAs play an important role in lung development, homeostasis, and 
pathogenesis. They also play a role in the regulation of cellular response to 
inhaled toxins and in regulation of in�ammatory and anti-in�ammatory 
processes. miRNAs are one of the primary epigenetic modi�ers that can
a�ect gene expression through post-translational gene silencing and mRNA 
degradation. Their improper regulation can lead to chronic infections and 
in�ammation. A study was done that obtained lung tissue samples from 15 
COPD patients and 11 subjects with normal lung function. 12
di�erentially expressed miRNA in COPD patients compared to subjects 
with normal lung function were identi�ed which showed to mostly target 
the nuclear lumen and transcription. Of the 12 di�erentially expressed 
miRNAs, miR-28-3p was most signi�cantly down-regulated and
miR-212-5p was most signi�cantly up-regulated [53]. More recently, a 
study showed that two constructed miRNA-mRNA pathways;
miR-126-5p and miR-130-5p-FOXO1 could be potential biomarkers for 
the diagnosis and treatment of COPD54. This year, a study showed that 
miR-126 was higher in COPD patients with acute exacerbation compared 
to stable COPD patients and healthy non-COPD patients and 
distinguished the groups. This led to the conclusion that the dysregulation 
of miR-126 relates to COPD susceptibility and acute exacerbation risk, but 
also is linked to severity and in�ammatory cytokines in COPD patients55.

Berkeley Pharma Tech Journal of Medicine | 73



Discussion

Chronic obstructive pulmonary disease provides unique grounds for 
exploration in new therapies. The compounding factors of several potential 
diseases or developmental miscues on a cellular level and beyond make it an 
issue to solve. However, this promotes much more de novo methods and 
research into the usage of several therapeutic methods in hopes to prevent 
such a prominent issue that 6.4% of Americans were diagnosed with it in 
2018. Focus on lung tissue dynamics and genetic development can be 
accomplished in a number of ways through gene therapy is one of the most 
promising and has great potential in future endeavors[JG5] . As an 
overarching �eld, gene therapy is on the forefront of pulmonary medicine 
given its success in diagnosis, treatment, and identi�cation in epidemiology 
of cystic �brosis, emphysema, and other common issues which all act as 
compounding factors categorized as COPD5-9.

Gene therapy works as a two pronged tool in lung therapy given the vast 
possibilities in the �eld between the potential delivery methods and actual 
genetic and cellular targets. The combination e�ect of these two issues leads 
to near endless possibilities in potential layouts for therapeutic strategies. In 
non-viral delivery methods, liposomes, nanoparticles, and electroporation 
are the more heavily researched aspects and provide a basis for most clinical 
studies1,3,15. Liposome based approaches and many potential nanoparticles 
limit immune response thanks to their endogenous nature and 
customizable size to desired scale yet the key di�erence comes when one 
looks at the e�ciency. Liposomes and liposomal NPs sacri�ce ease of use 
and optimal immunogenicity for e�ciency in many cases due to the body 
naturally developing barriers to them such as nuclear transport of their 
genetic material and signi�cant degradation before they can have a
signi�cant e�ect on the target15,17. Non-liposomal NPs are the most wide-
open area of research given the plethora of potential formulations.

PLGA and dendrimer nanoparticles for lung therapy have seen success 
given their idealized interaction. Yet, price points become an issue when one 
looks at the extensive research and time that must be put into each 
individual iteration of a given treatment method22,30. For example,

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taking a simple PLGA coated nanoparticle with targeting sites to deliver to 
lung epithelia for production in A1AT vs. the exact same base particle 
complemented to target ciliated cells will require entirely di�erent sets of 
trials and FDA compliance before any signi�cant levels of usage can occur. 
This is obviously necessary for safety and ethical concerns but presents a 
signi�cant holdup in advancement of NP as a therapy for COPD. 
Electroporation uses the manipulated electric �elds in cells to increase 
permeability signi�cantly. Targeting speci�city and overall quality of 
research eludes the �eld but it presents a purely physical method for gene 
therapy delivery and even assisting other methods should cell access present 
a signi�cant issue1,33. Viral methods for delivering gene therapy are 
composed of mostly adeno and adeno-associated viruses given the broad 
spectrum they o�er for behavior and ease of modi�cation35. Both o�er one 
of the more sought after qualities in gene therapy strategies in their 
integration abilities. The inherent function of viruses makes them ideal 
vectors that just need to be altered for the desired function. Immune 
response is an issue that can be improved upon but presents one of the only 
signi�cant issues in their usage as gene vectors44.

Targets for the readily available delivery methods is where the speci�city of 
COPD comes to the forefront of treatment. Inhalable therapies provide a 
unique avenue for treating pulmonary issues that might not be possible 
with other groups of diseases, thus it has been explored heavily with 
iterations of liposomal NP and viral vector bodies optimized for breaking 
through the heavy mucus and surfactant layers in lung tissues17,42-43,48. A 
variety of cells are still accessible through this minimally invasive gene 
therapy26. New stem cell therapy for COPD focus primarily on 
mesenchymal stem cells given their limited exhibition of pluripotent 
properties. One of the most well researched causes and potential targets for 
COPD is that of A1AT where gene alteration to the common ZZ mutation 
or to improve production in A1AT de�cient individuals has been seen to 
improve both physiological qualities and provided long term 
expression50-52. The �nal but potentially most broad method for focusing 
on the issues presented in COPD is that of working with miRNA using the 
aforementioned delivery methods. As a primary regulator for gene 
expression, in depth studies have found disparities in miRNA quality in

Berkeley Pharma Tech Journal of Medicine | 75



COPD patients53. Insertion of NPs to change miRNA expression for issues 
like lung irritation have also seen success56. Looking at these delivery 
methods in tandem with targeting goal is the only way to e�ectively 
evaluate the viability of a therapeutic strategy for COPD and look to 
improve the current state of understanding in treatment for it.

Conclusion

Although there are many potential treatment avenues, there needs to be a 
large focus on personalized medicine as the source of patients’ COPD can 
vary. Severity and associated symptoms are plentiful in COPD which only 
serves to necessitate more research into the �eld. Making strides towards 
being able to identify the best suited treatment for an individual will result 
in the most e�ective outcomes and treatments. The demonstration of
e�ectiveness in both speci�c cell targets in vitro as well as delivery methods 
must come together to formulate idealized gene therapy treatments. Issues 
present themselves in all areas discussed though they remain the primary 
modes of treatment in modern medicine. Understanding the subject and 
dynamics of both the disease and methods used is necessary to maintain 
good quality of care and building upon these to improve treatment of 
COPD.

Berkeley Pharma Tech Journal of Medicine | 76



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