Mental Illness in Young Adults

For the convention on 04.16.18 at the Health Science building, my team and I presented on the topic "Mental Illness in Young Adults." We spoke on depression, anxiety, and attention-deficit/hyperactivity disorder (ADHD). Depression is often mistaken for sadness. Depression is a mood disorder that affects a person's physical and mental health. The individual becomes emotionless and that's why they often cut themselves because they need to feel something even if it's pain. Research suggests that depression is due to lack of serotonin. However, it could also be a result of environmental stressors. The symptoms of depression are feelings of hopelessness, anger/irritability, appetite and sleep changes--whether they eat more or not at all. As it worsens, social withdrawal becomes a big issue, and thoughts of suicide and death. Risk factors are stress, use of illicit drugs, and symptoms of medical illness. 
This is the leading cause of disability in the US among people ages 15-44. Just over half (50.6%) of children aged 8-15 received mental health services in the past year. Lesbian, gay, bisexual, and transgender (LGBT) youth are twice likely to commit suicide than their heterosexual counterparts. Treatment for depression are selective serotonin reuptake inhibitors (SSRIs), anti-anxiety drugs, and therapy. 

Anxiety is continuous worry and fear. It also affects an individual's everyday life. Risk factors are stressors, chemical imbalances, and genetics. Anxiety disorders may include generalized anxiety, separation anxiety, panic disorder, posttraumatic stress disorder, and social anxiety. The symptoms and treatment are somewhat similar to depression. Half of those diagnosed with depression also suffer anxiety.

ADHD is a condition that includes hyperactivity, difficulty paying attention, and impulsiveness. It begins from childhood and progresses into adulthood. It may contribute to l0w self-esteem and difficulty forming relationships at school and work. The common symptoms are anger, anxiety, depression, mood swings, learning disability, in severe cases, autism and Tourette syndrome. The risk factors are maternal drug use, environmental toxins, premature birth, and another relative suffering from mental health.
More than 5 million children are currently diagnosed with ADHD. Two out of 3 people with ADHD suffer from another mental, emotional, and behavioral disorder. Only 77% of children ages 2-17 receive treatment. Treatments include cognitive-enhancing medication, support groups, anger management, and anti-hyperactivity drugs. Also, I highly suggest family therapy.

PLASMA MEMBRANE & TRANSPORT OF IONS

There are three ways in which molecules pass through the cell membrane, and they are passive transport, facilitated diffusion, and active transport. The first transport does not require ATP, so molecules move across the cell without the need for energy. Facilitated diffusion is when ions move through the membrane via the aid of a membrane protein. During this diffusion, ions can move in different directions--uniport, symport, and antiport. Active transport requires ATP to move ions through the cell against the electrochemical gradient. 

An example of symport transport is the Na+/glucose symporter. An example of the antiporter is the Na+/K+-ATPase pump. Ths is the process of moving sodium (Na+) and potassium (K+) ions across the plasma membrane. 

http://humanbiologylab.pbworks.com/w/page/45302491/Resting%20Cellular%20Membrane%20Potential

There is a higher concentration of Na+ in the extracellular side of the cell and a higher concentration of K+ inside the cell. So, three sodium comes into the cell and two potassium goes out of the cell. Homeostasis of the membrane potential is associated with the cell's electrical charge and ion concentration. So, a membrane potential of a cell at rest is called the resting potential, a value of -70mV. When an impulse is fired in a neuron down the axon, it's referred to as an action potential (AP). AP are generated by voltage-gated channels embedded in a membranre. A stimulus first causes sodium channels to open, so the neuron becomes more positive becoming depolarized. It takes quite a bit for the K+ channels to open up, but when they do, it rushes out of the cell, sort of reversing the depolarization. At that time, the Na+ channels start to close. The AP then goes below -70mV (hyperpolarization) since the K+ channels stay open for a longer time. Gradually, the ion concentrations go back to the resting level, returning to -70mv. 

 

https://www.moleculardevices.com/what-action-potential

CELL & MOLECULAR BIOLOGY

Summary of Today's knowledge

Secretory proteins are synthesized in the endoplasmic reticulum (ER) by the initiation of protein synthesis on free ribosomes, binding of SRP to nascent polypeptide, binding SRP, polypeptide, and ribosome to SRP receptor, then dissociation of SRP from its receptor, and translocation across the membrane of the endoplasmic reticulum, and the cleavage of signal sequence. Translation arrest promotes the subsequent translocation of the nascent polypeptide chain through the Sec61 by targeting the entire complex to the rough ER by binding to the SRP receptor on the membrane. This binding leads to the release of SRP from the ribosome and the signal sequence of the growing polypeptide chain. 

Unfolded protein response (UPR) is activated if there's an excess of unfolded protein that's accumulated in the ER. Activation of UPR pathway leads to the expansion of the ER and production of additional chaperones that meet the need for increased protein folding. If these changes are insufficient to adjust protein folding in the ER to a normal level, the sustained activity of the unfolded protein leads to programmed cell death (apoptosis), thereby eliminating cells that are unable to properly fold proteins from the body. There are 3 main receptors associated with this pathway--IRE1, ATF6, and PERK. IRE1 cleaves pre-mRNA of a transcription factor, XBP1. ATF6 is cleaved to produce active ATF6 transcription factor while PERK is a protein kinase that phosphorylates eukaryotic initiation factor 2 (eIF2). 

The fusion of a transport vesicle with its target involves two events. First, the transport vesicle must recognize the correct target membrane; for instance, a vesicle carrying lysosomal enzymes has to deliver its cargo only to lysosomes. Second, the vesicle and target membranes must fuse, delivering the contents of the vesicle to the target organelle. The initial interaction between vesicles and target membranes is mediated by tethering factors and Rab-proteins. 

Also, lysosomal storage diseases such as Gaucher's disease. This disorder is caused by a failure of lysosomes to degrade substances that they normally break down. The resulting accumulation of nondegraded compounds leads to an increase in the size and number of lysosomes within the cell, resulting in pathological consequences to affected organs.
Zellweger syndrome is a recessive genetic disorder that results from mutations in the Pex proteins that are responsible for peroxisomes assembly. Most peroxisome transmembrane proteins are synthesized in the ER and transported in vesicles that fuse to form peroxisomes. Other transmembrane proteins are synthesized on free ribosomes in the cytosol and targeted to the peroxisome membrane by a membrane-targeting signal.
Two protein modifications that occur in the ER: (i) glycosylation and (ii) addition of GPI anchor
The former plays a role in determining protein structure, function, and stability. It helps to prevent protein aggregation in the ER and provides signals that promote protein folding and subsequent sorting in the secretory pathway. Proteins are glycosylated on asparagine residues [N-linked] or Ser or Thr residues [O-linked]. The N-linked sugars added to proteins in the ER are modified within the Golgi. Those proteins destined for lysosomes are phosphorylated by mannose residues and mannose-6-phosphate serves as a targeting signal that directs their transport to lysosomes from the trans-Golgi network. The latter attaches to glycolipids. GPI consists of to fatty acids chain--inositol and ethanolamine.
Lastly, cotranslational translocation is the binding of growing polypeptide chain to the signal recognition particle through a translocon which is driven by protein synthesis while posttranslational translocation is driven by chaperone protein called binding immunoglobulin protein (BiP).