When muscle cells undergo injury, quiescent satellite cells are released from beneath the basement membrane
. They become activated and re-enter the cell cycle. These dividing cells are known as the “transit amplifying pool” before undergoing myogenic differentiation to form new (post-mitotic) myotubes.
How do satellite cells help increase muscle size?
Satellite cells possess a single nucleus that acts as a control center, which regulates gene expression.
When prompted by tissue damage, satellite cells replicate and differentiate into mature muscle cells by fusing to existing fibers
. This is how they become new muscle protein strands and assist with muscle repair.
What is the role of satellite cells in mature muscle?
Satellite cells are the primary stem cells in adult skeletal muscle and are
responsible for postnatal muscle growth, hypertrophy and regeneration
. Since their original identification, satellite cells have been considered as unipotent myogenic precursor cells.
How do muscle cells repair?
When the muscle is damaged, these cells are stimulated to divide. After dividing, the cells fuse with existing muscle fibres, to regenerate and repair the damaged fibres
. The skeletal muscle fibres themselves, cannot divide. However, muscle fibres can lay down new protein and enlarge (hypertrophy).
What is the main function of satellite cells?
glial cells that surround some neurons in the peripheral nervous system. Their role is not fully understood, but it is thought they
provide nutrient support and protection
. They may also help to regulate the neuronal environment and be involved in neurotransmission.
How do muscle satellites activate?
Signals to activate satellite cells
Upon muscle injury,
a combination of signals is generated by damaged myofibers, blood vessels, and immune cells to wake up the quiescent satellite cells
. The activated satellite cells also signal back to the environment to orchestrate orderly muscle regeneration (Fig. 1).
Are satellite cells needed for hypertrophy?
Collectively their studies have demonstrated that
satellite cells are not requisite for hypertrophy in the short term
, but they are essential for sustained muscle growth in the long term.
Does smooth muscle have satellite cells?
Satellite cells help to repair skeletal muscle cells.
Smooth muscle tissue can regenerate from stem cells called pericytes
, whereas dead cardiac muscle tissue is replaced by scar tissue. Aging causes muscle mass to decrease and be replaced by noncontractile connective tissue and adipose tissue.
What happens to satellite cells as we age?
Therefore, aging
disrupts satellite cell self-renewal
. Specifically, age-related cell extrinsic changes in expression of signaling ligands, combined with satellite cell-intrinsic alterations in the ability to appropriately respond to signals, disrupt asymmetric cell division and limit satellite cell self-renewal.
What is the correct sequence of events contributing to muscle regeneration that involves satellite cells?
An Introduction to Muscle Regeneration. Muscle regeneration occurs in three sequential but overlapping stages:
1) the inflammatory response; 2) the activation, differentiation, and fusion of satellite cells; and 3) the maturation and remodeling of newly formed myofibers
.
Do satellite cells produce myelin?
Key Points. There are two kinds of neuroglia in the peripheral nervous system (PNS): Schwann cells and satellite cells.
Schwann cells provide myelination to peripheral neurons
.
What type of cells do represent muscle satellite cells?
The
mesoderm-derived satellite cells
are a heterogeneous population of adult stem cells of the skeletal muscle [2]. In the absence of muscle cell injury, the satellite cells remain dormant and rest in the G0 phase of the cell cycle, which is the quiescent state.
How does muscle regeneration work?
Muscle regeneration usually starts during the first 4–5 days after injury, peaks at 2 weeks, and then gradually diminishes 3 to 4 weeks after injury. It's a multiple steps process including
activation/proliferation of SC, repair and maturation of damaged muscle fibers and connective tissue formation
.
How do muscles develop grow and repair?
Muscle hypertrophy occurs when the fibers of the muscles sustain damage or injury
. The body repairs damaged fibers by fusing them, which increases the mass and size of the muscles. Certain hormones, including testosterone, human growth hormone, and insulin growth factor, also play a role in muscle growth and repair.
How does satellite cell work and regenerate the skeletal muscle fiber?
Satellite cells proliferate following muscle trauma and form new myofibers
through a process similar to fetal muscle development
. After several cell divisions, the satellite cells begin to fuse with the damaged myotubes and undergo further differentiations and maturation, with peripheral nuclei as in hallmark.
Are satellite cells Neuroglia?
Satellite glial cells are a type of glia found in the peripheral nervous system
, specifically in sensory, sympathetic, and parasympathetic ganglia. They compose the thin cellular sheaths that surround the individual neurons in these ganglia.
Where are muscle satellite cells?
Abstract. Skeletal muscle satellite cells are quiescent mononucleated myogenic cells, located
between the sarcolemma and basement membrane of terminally-differentiated muscle fibres
.
What do satellite cells protect?
Satellite cells are small glia that surround neurons' sensory ganglia in the ANS. These resemble the astrocytes of the CNS and assist in
regulating the external chemical environment
. PNS satellite glia are very sensitive to injury and may exacerbate pathological pain.
What would happen if satellite cells were destroyed?
In this study, Ramkumar Sambasivan and colleagues at the Pasteur Institute in Paris discovered that when satellite cells were destroyed in mice,
other types of cells were unable to repair muscle damage
. This study tells us more about how different cell types work together to grow new muscle.
What promotes repairing and rebuilding of muscle tissue?
Thus, in addition to surgical techniques,
physical therapy
is a noninvasive/minimally invasive way to promote muscle tissue repair and regeneration. It is especially used for rehabilitation after injuries and muscle tissue transfer, or to treat chronic muscle loss.
Do you think muscles can regenerate when damaged?
Skeletal muscle can regenerate completely and spontaneously in response to minor injuries, such as strain
. In contrast, after severe injuries, muscle healing is incomplete, often resulting in the formation of fibrotic tissue that impairs muscle function.
How do smooth muscles heal?
The most frequently used drugs in the therapy of visceral smooth muscle spasms are substances that relax smooth muscles (with antimuscarinic activity/atropine-like/or with non-specific activity/papaverine-like direct spasmolytics) and analgesics (opioids or nonsteroid antiinflammatory drugs-NSAID).
