BIO307 Lecture 4: Cell Communication

Molecular and Cellular Biology [BIO307]

• Course name: Molecular and Cellular Biology
• Course code: BIO307
• School: Biotechnology

Lecture 4: Cell Communication and Signaling I

• Topic: Cell communication and signaling
• Focus: The "fight or flight" response as an example of cell signaling
• Reference: Campbell Biology, 11th edition, Chapter 11, pages 212-233

Neural Activity Combines with Hormones in the Bloodstream

• The body reacts to stressful situations through a combination of neural and hormonal signals

• The brain initiates the process by sending signals to the adrenal glands, triggering hormonal release

• Hormones, such as adrenaline and cortisol, travel throughout the body via the bloodstream, affecting various organs and tissues

• Specific Responses:

  • Lungs: Increased breathing rate
  • Liver: Converts glycogen to glucose for energy
  • Muscles: Become tense
  • Eyes: Pupils dilate
  • Heart: Accelerates
  • Stomach: Slows digestion
  • Other organs: Experiences other physiological changes

• Integration of Neural and Hormonal Responses: Neural input causes an immediate reaction, and hormones enhance and sustain the response.

Why you Experienced these Physiological Changes

• Fight-or-Flight Response: The body's natural reaction to perceived danger

• Cell Communication: Brain detects stress → triggers release of adrenaline and cortisol (hormones) → travel through bloodstream → impact various parts of the body.

• Physiological Changes:

  • Increased heart rate, blood flow to the brain (think clearly)
  • Faster breathing; supplying more oxygen to the brain
  • Increased alertness and focus; better response time

How Adrenaline Induces These Effects

• Question: How does adrenaline lead to these responses?
• The specific mechanisms behind those responses are not provided

Cell-Cell Communication

• Local Communication:
  • Gap junctions: Direct connection between cells; allowing for the passage of ions and molecules
  • Contact-dependent signals: Direct contact between cell surfaces; typically involve cell membrane proteins
  • Synaptic signaling: Neurotransmitters released into a synapse and bind to receptors on the target cell
  • Autocrine signals: A cell secretes a signal that acts on its own receptors
  • Paracrine signals: A cell secretes a signal that acts on neighboring cells
• Long Distance Communication:
  • Endocrine signaling: Hormones are released into the bloodstream; signaling molecules
  • Nervous system: Neurons transmit signals via electrical impulses, and/or release neurohormones into the bloodstream

Signal Transduction Pathway

• The process of converting a signal on a cell's surface into a cellular response
• Involved a series of steps.
  • Reception: A signaling molecule binds to a specific receptor on the target cell.
  • Transduction: Converts the signal. This involves relay molecules (often proteins)
  • Response: A cell's response; which can lead to different outputs.

Cell-Cell Communication Techniques

• Detecting and measuring the expression levels of specific genes or proteins involved in cell communication
• Co-culture experiments: Different cell types are cultured together, and the effects of direct cell-to-cell communication and paracrine signaling can be assessed.
• Scrape loading and dye transfer: Assessment of gap junction communication
• Live-cell imaging: Monitor real-time behavior of cells to direct and paracrine signals

Experimental Design and Hypothesis Testing

• Scientific Method: The process used by researchers to investigate a question or problem
  • Describe a Question/Problem: State the question to study
  • Propose Hypotheses/Solutions: Develop possible explanations
  • Test a Hypothesis/Solution: Design experiments to test the proposed hypotheses
  • Form Conclusions: Collect and analyze data to determine and support/reject hypotheses
  • Communicate Conclusions: Share findings with a wider audience
• Radiotherapy and its relation to cardiovascular issues:
  Radiotherapy: Standard breast cancer treatment
  Side effects of radiation: potential complications The process of radioprotective drug development
• Atherosclerosis:
• Radiation-induced Atherosclerosis: How are cells damaged with radiation exposure

Additional Notes

• The presentation includes a variety of diagrams and visual aids
• Multiple references are provided for further learning